CN100528097C - Thermal hemostasis and/or coagulation of tissue - Google Patents

Abstract

Energy delivery systems and methods are provided for use in biological tissue. The energy delivery system includes a handle, a radiofrequency (RF) generator, and an electrode array. The electrode array includes two or more pair of bipolar electrodes slideably coupled in channels of the handle. The bipolar electrodes electrically couple to the RF generator, and the electrode array is configureured to deliver a balanced energy density in a target volume of the biological tissue. The balanced energy density delivered by the electrode array results in generation of a hemostatic plane of tissue.

Description

Thermal hemostasis and/or coagulation of tissue

Associate application

This application claims the benefit of US Patent Application No. 60/620,757, filed October 20, 2004. This application is also a continuation-in-part of U.S. Patent Application No. 10/890,055, filed July 12, 2004, U.S. Patent Application No. 10/890,055, filed March 15, 2004, application No. 10 /800,451, a continuation-in-part of U.S. Patent Application No. 10/800,451, a continuation-in-part of International Application No. PCT/US03/21766, filed July 11, 2003, and filed in 2003 Continuation-in-Part of US Patent Application Serial No. 10/413,112, filed April 14, which claims the benefit of US Patent Application Serial No. 60/405,051, filed August 21, 2002.

technical field

The present invention relates generally to tissue coagulation and tissue resection, and more particularly to the use of radio frequency ("RF") energy to create a plane of tissue coagulation.

Background technique

Standard surgical procedures such as resection, used to treat a variety of diseases including tumors, trauma to different organs such as liver, kidney and spleen, have some key drawbacks. These disadvantages affect, for example, efficacy, morbidity and mortality. A fundamental problem, for example, is insufficient control of blood loss during tissue resection.

In an attempt to help overcome this limitation, various unipolar and bipolar RF devices have been created. These devices act as conduits to carry power from the RF generator. These devices include electrocautry pencils and probes of various types and configurations, which are available from many different manufacturers such as Bovie, ValleyLab, and TissueLink. The algorithms currently used by these devices in surgical procedures typically provide a constant amount of delivered energy, with the energy level and duration directly controlled by the user. This approach has fundamental drawbacks that limit its usefulness in typical clinical settings.

Disadvantages associated with delivering a constant amount of energy into the target tissue include the inability to automatically adjust the correct level of energy delivery appropriately to the condition of the resected tissue. After the initial application of energy to the target tissue, the properties of the tissue begin to change. With these changes, the energy application should also be varied to maintain optimal energy application. Typical methods of delivering hemostatic energy into target tissue are unsuitable because they rely on the user to regulate energy delivery with little or no information or guidance regarding the changing state of the target tissue. As a result, the final amount or duration of delivered energy may not be sufficient to produce hemostasis.

Furthermore, typical energy delivery systems rely on the user to set an initial level of energy delivery with little or no pertinent information about the condition of the target tissue being treated. Thus, when using typical energy delivery systems, the initial application of energy may be significantly lower or higher than required. When an insufficient amount of energy is applied to the target tissue, the hemostatic effect of the tissue cannot be obtained. Likewise, if the duration of energy application is too short, proper hemostasis will not be achieved. When too high an amount of energy is applied to the target tissue, the result is charring of the target tissue. This charring can cause continued transfer of tissue transfer energy to the tissue; it can also create an overly superficial depth of the treated tissue, resulting in poor hemostasis.

Incorporation by reference

Each publication and/or patent application mentioned in this specification is hereby incorporated by reference in its entirety as if each individual publication and/or patent application were specifically and individually indicated to be incorporated by reference herein. Same.

Description of drawings

Figure 1 is a tissue coagulation system in one embodiment.

2 and 3 are schematic diagrams of an energy director guide in one embodiment, including various views.

FIG. 4A shows a resistive network model of an energy director configuration comprising six energy directors in the embodiment of FIGS. 2 and 3 .

Figure 4B shows a table including power consumption values corresponding to energy director configurations providing balanced energy in the embodiment of Figure 4A.

Figure 4C shows a table including power consumption and spacing information corresponding to an energy director configuration providing balanced energy in the embodiment of Figure 4A.

Figure 5A shows a resistive network model of an energy director configuration comprising 8 energy directors in another embodiment.

Figure 5B shows a table including power consumption values corresponding to energy director configurations providing balanced energy in the embodiment of Figure 5A.

Figure 5C is a table including power consumption and spacing information corresponding to an energy director configuration providing balanced energy in the embodiment of Figure 5A.

Figure 6A shows a resistive network model of an energy director configuration comprising 6 energy directors (5 zones) in another embodiment.

Figure 6B shows a table including power consumption information corresponding to an energy director configuration providing balanced energy in the embodiment of Figure 6A.

Figure 6C is a table including current and spacing information corresponding to an energy director configuration providing balanced energy in the embodiment of Figure 6A.

Figure 7 is an energy director guide and energy director in another embodiment.

Figure 8 is a side view of an energy director guide employing direct coupling in another embodiment.

9 is a schematic diagram of a circuit board for an energy director guide in the embodiment of FIG. 2 .

Figure 10 is a side view of an energy director guide employing indirect coupling in one embodiment.

Figure 11 shows an energy director guide provided in one embodiment for independently controlling the insertion depth of each energy director.

12 and 13 illustrate the operation of the tissue coagulation system for generating tissue avascular volume in the embodiment of FIG. 2 .

Figure 14 is a flow diagram of the operation of the tissue coagulation system in one embodiment.

Figure 15 is a flow diagram of controlling tissue coagulation based on temperature parameters, in one embodiment.

Figure 16 is a flow diagram of controlling tissue coagulation according to impedance and time parameters, in one embodiment.

Figure 17 is a flow diagram of controlling tissue coagulation based on impedance parameters, in one embodiment.

Figure 18 is a graph of impedance and power versus time for controlling tissue coagulation, in one embodiment.

Figure 19 is a graph of time versus impedance depicting the effective tissue coagulation cycle, in one embodiment.

Figure 20 is a graph of time versus impedance depicting undesired low level power delivery, in one embodiment.

Figure 21 is a graph of time versus impedance depicting undesirably high levels of power delivery, in one embodiment.

FIG. 22 is a flow diagram of efficient tissue coagulation in the embodiment of FIG. 19 .

Figure 23 is a graph of applied power (percentage) versus time for damped wave energy delivery in one embodiment.

24 is a graph of applied power (percentage) versus time for damped wave energy delivery including increasing power adjustments, under one embodiment.

25 is a graph of applied power (percentage) versus time for damped wave energy delivery including reduced power adjustments, under one embodiment.

Figure 26 shows a flexible or semi-flexible guide having flexibility on both sides in another embodiment.

Figure 27 shows a flexible or semi-flexible guide having flexibility on one side in another embodiment.

Figure 28 is an array of energy directors including, in one embodiment, an attachment portion that provides for simultaneous insertion or withdrawal of energy directors into a target tissue.

Figure 29 is an array of energy directors including connections to energy directors in another embodiment.

Figure 30 shows an energy director that supports the delivery of various agents into target tissue, in one embodiment.

Figure 31 shows an energy director capacitively coupled to target tissue in one embodiment.

In the drawings, the same reference numerals indicate the same or substantially similar elements or actions. To easily identify a discussion of any particular element or act, the most significant digit in a reference number indicates the reference number that first mentions that element (eg, element 102 is first mentioned and discussed in FIG. 1 ).

Detailed ways

A tissue coagulation system including various components and methods is described in detail herein. The tissue coagulation system produces an avascular volume of coagulated tissue that facilitates bloodless or near bloodless resection of various biological tissues from various organs including, for example, the liver, spleen, kidneys, and various other organs of the body. The terms coagulation, thermal coagulation, ablation, coagulative ablation and thermal ablation all have the same meaning and are used interchangeably in the following description.

In the following description, numerous specific details are introduced to provide a thorough understanding and enablement description of embodiments of the tissue coagulation system. However, one of ordinary skill in the relevant art will recognize that a tissue coagulation system can be implemented without one or more of these specific details, or with other components, systems, etc. Additionally, well-known structures or operations are not shown or described in detail to avoid obscuring the context of the tissue coagulation system.

Figure 1 is a tissue coagulation system 100 in one embodiment. The tissue coagulation system 100 includes an energy director guide 102, or guides, and two or more pairs of bipolar energy directors 104, also referred to herein as electrodes. Tissue coagulation system 100 may assist in thermal coagulation necrosis of soft tissue during tissue resection. Alternative embodiments of the tissue coagulation system 100 may include monopolar energy directors as well as various combinations of bipolar and monopolar energy directors. Energy director 104 is configured for insertion into a volume of biological tissue 199 . The energy director guide 102 configures the energy director to provide a substantially uniform distribution of power or energy through the entire volume of tissue, which is referred to as target tissue or target tissue volume. The target tissue volume includes, but is not limited to, a volume extending in a radius of about 1 centimeter ("cm") around each energy director 104 along the energy director's 104 conduction direction. The target tissue volume forms at least one plane of coagulated tissue.

Energy director guide 102 and energy director 104 are coupled between at least one generator 110 or power source, but are not limited thereto. In one embodiment the energy director 104 is coupled to the generator 110 through the energy director guide 102 . In addition, the energy controller 104 may also be directly coupled to the generator 110 through wires, cables or other conduits.

With the bipolar configuration of the energy director 104 , one electrode of the electrode pair acts as a source, while the other electrode of the electrode pair acts as a sink for energy received from the generator 110 . Therefore, one electrode is arranged at an opposite voltage (polarity) to the other electrode to direct energy from the generator from one electrode to the other. A bipolar electrode arrangement ensures a more localized and smaller thermal coagulation volume, although the embodiment is not so limited.

The Alternate Polarity series of Energy Directors includes various series combinations of Alternate Polarity. For example in an embodiment using 6 energy directors, the alternating polarities are: positive (+), negative (-), +, -, +, -. An alternating polarity series is: +, +, -, -, +, +. Another series of alternating polarity is: -, -, +, +, -, -. Yet another series of alternating polarity is: +, +, +, -, -, -. Yet another series of alternating polarities may include: +, +, -, +, -, -. These examples are exemplary only, and the tissue coagulation system 100 described herein is not limited to 6 electrodes or these alternating polarities.

When properly configured for insertion into a particular tissue type, the energy director 104 has a shape and pattern that supports coupling to the target tissue and allows the energy director 104 to deliver sufficient energy to cause tissue hemostasis, such as by coagulation of the tissue, thereby assisting the selected tissue volume resection. The energy director 104 of one embodiment includes a rigid shaft of sufficient stiffness to be easily pushed into the target tissue 199 and coupled to the tissue 199 while maintaining its shape.

The energy director 104 terminates in an atraumatic or minimally invasive tissue-invasive tip of various configurations known in the art to be suitable for the tissue type of the target tissue 199 and known in the art. Energy director tip configurations in one embodiment include, but are not limited to, fully rounded tips, flat tips, blunt tips, and rounded tips. These configurations can assist in the insertion of the energy director into different types of target tissue while protecting the user from sharp points that could injure the user during normal handling. This is especially important because the energy director may be contaminated with potentially lethal materials, including hepatitis C and human immunodeficiency virus ("HIV"), which can be transmitted to the user through a puncture wound.

The energy directors in one embodiment can have many different sizes, depending on the energy transfer parameters (current, impedance, etc.) of the respective system. For example, an approximate range of energy director diameters is 0.015 inches to 0.125 inches, but is not limited thereto. The approximate range of energy director length is 4 cm to 10 cm, but is not limited thereto. Energy directors include materials selected from conductive or plated plastics, superalloys including shape memory alloys and stainless steel, to name a few.

Additionally, an array of energy directors may include energy directors of different sizes and lengths. For example, an energy director array in one embodiment includes a linear array of six energy directors, where the energy directors at the ends of the array are 16-gage electrodes and the four energy directors forming the center of the array It is a No. 15 electrode. The use of energy directors with different diameters allows balancing the energy/energy density in the target tissue, for example, by reducing the total energy expenditure in the target tissue located at the end of the array (slightly smaller energy directors), and thus limiting/controlling the impact on excess energy Tissue effects (necrosis) of the controller array. Thus, in addition to energy director spacing, the use of energy directors with different diameters provides an additional means of control over the energy balance in the target tissue.

The energy director 104 in various alternative embodiments includes a material that supports bending and/or shaping of the energy director 104 . Additionally, the energy director 104 in alternative embodiments may include non-conductive materials, coatings, and/or wraps of various sections and/or portions along the axis of the energy director 104 that are suitable for the respective energy delivery requirements of the method and/or target tissue type.

Generator 110 of one embodiment delivers a predetermined amount of energy at a selectable frequency to coagulate and/or cut tissue, but is not limited thereto. Generator 110 in one embodiment is an RF generator that supports an output power range of about zero to 200 watts, an output current range of about 0.1 amps to 4 amps, a typical range of output impedance of about 2 to 150 ohms, and a frequency range of is about 1 kHz to 1 MHz, but is not limited thereto.

It will be appreciated that the choice of generator electrical output parameters to monitor or control the tissue coagulation process may vary widely depending on tissue type, operator experience, technique and/or preference. For example, in one embodiment a common voltage is applied to all energy directors in the array simultaneously. In another embodiment, the operator may choose to control the current of individual energy directors in the array, or the total current of the array as a whole.

In addition, voltage variations can be applied to each energy director to achieve a constant current output from each energy director. Alternatively, a constant power output per energy director may be sought in some approaches. In addition, a voltage change or phase difference between energy directors can be implemented to achieve a predetermined temperature distribution in the tissue, which is monitored by temperature sensors in the tissue or by displaying the temperature distribution using techniques known in the art. Accordingly, the choice of electrical output type, sequence and level, and distribution of energy directors in the array should be considered to have wide variation within the scope of the present invention.

Various target tissue-related geometric factors also affect tissue heating during coagulation. They include tissue margins as well as coagulation surface volumes. As the amount of surface area removed increases, so does heat loss. Coagulation edges, sides and ends all have an effect on heat loss during coagulation.

The coagulation system of one embodiment ablates target tissue by heating the tissue uniformly across energy directors. To achieve uniform heating, the current density in the tissue immediately surrounding the energy conduits should not be significantly higher than the current density in the tissue between the energy conduits. For example, considering the relatively small size of the electrodes, the tissue/energy conduit interface is also small. This results in higher current densities around the energy conduits, resulting in predominant heating of the immediate vicinity of the electrodes, increasing the potential for unwanted tissue charring, and ultimately limiting the energy delivered to the tissue. Solutions to this problem presented here include the use of large tissue/energy conduit contact areas, cooling of the electrodes, and introduction of more conductive materials such as hypertonic saline in the electrode area.

Tissue coagulation system 100 may include any number of other components, such as controller 120, to semi-automatically or automatically control the delivery of energy from the generator. For example, the controller can increase the power output to the electrodes, control temperature when the energy controller includes a temperature sensor or when receiving temperature information from a remote sensor, and/or monitor or control impedance, power, current, voltage and/or Other output parameters. The function of the controller 120 can be integrated with the function of the generator 110, and can also be integrated with other components of the tissue coagulation system 100, or can be in the form of an independent unit coupled between the components of the tissue coagulation system 100, but not limited to this.

Additionally, the tissue coagulation system 100 may include a display 130 that provides a display of heating parameters, such as temperature, impedance, power, current, timing information, and/or voltage output by the generator for one or more energy directors. The function of the display 130 can be integrated with the function of the generator 110, and can also be integrated with other components of the tissue coagulation system 100, or can be in the form of an independent unit coupled between the components of the tissue coagulation system 100, but not limited here.

In various alternative embodiments, the tissue coagulation system 200 may also include a biocompatible heat shield 140 . Heat shield 140 is used to protect the organs and tissues surrounding target biological tissue 199 from the procedures described herein associated with treatment with tissue coagulation system 200 .

The arrangement of energy directors described herein controls the distribution of energy applied to the target tissue. Likewise, the energy director configurations described herein support substantially uniform energy distribution and/or current density, and correspondingly more uniform temperature in the target tissue volume. An example of this involves the use of RF energy, as described below, for very pairs of energy directors by using relatively small spacing between the outer energy directors of the linear energy director array and energy control of the center of the energy director array. relatively large spacing between the detectors to obtain a generally uniform energy distribution. Energy director guides are used to establish and maintain energy director spacing, as described below. An example of a tissue coagulation system 100 in one embodiment includes the InLine ^™ Bipolar RF Linear Coagulation System (also known as the InLine ^™ Radio Frequency Coagulation Apparatus (“ILRFA”)), available from Resect Medical ^™ of Fremont, CA.

2 and 3 are schematic illustrations of energy director guide 102 including various viewing angles in one embodiment. Dimensions shown are in inches. Energy director guide 102 includes a support body having a linear series of channels 202-212 that can receive or carry energy directors. The support of one embodiment includes first and second end portions having a surface extending between the first and second end portions. Channels 202-212 may also be referred to as holes or openings, but are not limited to such.

(聚醚酰亚胺)和丙烯腈丁二烯苯乙烯(“ABS”)塑料，但并不局限于此。使用本领域公知众多的任意技术和材料来生产能量控制器导向装置。例如，一个实施方案的能量控制器导向装置可采用单片模制设计来形成。此外，一个替代实施方案的能量控制器导向装置可采用两个或更多个分离的片并采用本领域公知技术组装形成所述导向装置来形成。Various alternative embodiment energy director guides may include a non-linear series of channels, and various combinations of linear and non-linear series of channels. The energy directors of one embodiment alternate polarity, or alternatively, alternate polarity in groups or sets as described above, although the embodiment is not limited thereto. The configuration of the channels 202-212 in the guide supports the delivery of an energy distribution or radiation pattern in the tissue by the energy director that provides sufficient and uniform coagulation in the target tissue volume. Typically, a coagulation width ranging from approximately 0.5 cm to 1.5 cm is employed to aid resection, although the embodiments are not limited thereto. The energy director guides comprise biocompatible materials such as non-conductive plastics such as polycarbonate plastics,

(polyetherimide) and acrylonitrile butadiene styrene ("ABS") plastics, but not limited thereto. The energy director guides are produced using any of a number of techniques and materials known in the art. For example, the energy director guides of one embodiment may be formed using a one-piece molded design. Furthermore, an alternative embodiment energy director guide may be formed using two or more separate pieces assembled to form the guide using techniques known in the art.

Six channels are shown for exemplary purposes, alternative embodiments may include a different number of channels. One alternate embodiment includes 4 channels, while another alternate embodiment includes 8 channels. The spacing between channels 202-212 varies according to the total number of energy directors received in energy director guide 102, as described below. Typically, when coupling energy directors to the generator, the channels closest to the center (206 and 208 in this embodiment) have the greatest relative spacing between them, taking into account the electromagnetic coupling of the energy directors, while the channels closest to the ends The relative spacing between the channels (202/204 and 210/212 in this embodiment) is minimal.

As noted above, uniform energy distribution is important when generating an avascular volume of tissue suitable for bloodless or near bloodless resection. The energy director guides 102 described herein provide uniform energy distribution by employing channel spaced energy directors and thus energy director configurations, which account for electromagnetic coupling between adjacent energy directors. The energy director guide 102 in one embodiment includes six channels 202-212 operatively accepting three pairs of bipolar energy directors. The spacing between channels 202 and 204 is approximately 0.2995 inches. The spacing between channels 204 and 206 is approximately 0.3285 inches. The spacing between channels 206 and 208 is approximately 0.3937 inches. The spacing between channels 208 and 210 is approximately 0.3285 inches. The spacing between channels 210 and 212 is approximately 0.2995 inches.

Guide channel spacing that provides relatively uniform energy distribution is generated using a resistive network model, but is not limited thereto. Figure 4A shows a resistive network model 400 of an energy controller configuration comprising six bipolar energy directors in the embodiment of Figures 2 and 3. Each of the six bipolar energy directors is represented by nodes 1-6 A representation of where each node is assigned an alternate polarity 499, but the assigned polarity is not restrictive in this instance. As described below, model 400 includes a number of resistors R1-R19 coupled between nodes 1-6 and current source 402 in various configurations. Current source 402 is optionally selected to produce a current of 750 milliamps ("mA"), although the model is not limited thereto.

In general, the resistive configuration of module 400 simulates relative power dissipation, including coupling effects between various alternating polarity node combinations in a tissue volume ("zone") between energy directors (nodes), as further described below. Considering that biological tissue has a resistivity (resistance per unit volume) proportional to the spacing between energy directors, the resistance value of the model was iteratively changed to represent different channel spacings.

Referring to FIG. 4A , resistor R1 simulates the power dissipation of zone 1 as a result of current flowing between nodes 1 and 2 . Likewise, resistors R2, R3, R4 and R5 simulate their power consumption, respectively, as a result of the current flowing between the nodes defining each zone 2-5. A series combination of resistors R6, R7 and R8 is coupled between nodes 1 and 4 and simulates power dissipation across regions 1, 2 and 3 as a result of current flowing between nodes 1 and 4. A series combination of resistors R9, R10 and R11 is coupled between nodes 3 and 6 and simulates power dissipation across regions 3, 4 and 5 as a result of current flowing between these nodes. A series combination of resistors R12, R13 and R14 is coupled between nodes 2 and 5 and simulates power dissipation across regions 2, 3 and 4 as a result of current flowing between nodes 2 and 5. Finally, the series combination of resistors R15, R16, R17, R18 and R19 is coupled between nodes 1 and 6 and simulates the power across regions 1, 2, 3, 4 and 5 as a result of the current flowing between nodes 1 and 6 consume. FIG. 4B shows a table 450 including power consumption values for the embodiment of FIG. 4A that correspond to energy director configurations that provide balanced energy.

FIG. 4C shows a table 480 including power consumption and spacing information for the embodiment of FIG. 4A corresponding to an energy controller configuration providing balanced energy. The table 480 includes the total power consumption 482 for each zone in the resistive network model 400 . As noted above, in the embodiment of Figure 2, the balanced energy director configuration uses non-uniform channel spacing in the energy director guides to account for the effect of electromagnetic coupling. In determining the total power consumption per zone 482, the resistance values of the zones in the array are iteratively varied until the total power consumption per zone 482 is approximately equal; the spacing between each zone is proportional to the resistance value. The total power consumption of zones 1-5 in the balanced energy director configuration is approximately 246 milliwatts (mW), 248 milliwatts (mW), 250 milliwatts (mW), 248 milliwatts (mW), and 246 milliwatts, respectively (mW), but not limited to this. Therefore, the power consumption or distribution among the zones is substantially uniform.

Using the final value of total power consumption/zone 482, the spacing ratios per zone 484 and 486 are generated. In one embodiment, 2 different spacing ratios per zone 484 and 486 are created, although the embodiment is not so limited. The first spacing ratio for each zone 484 refers to the spacing of the zone to the closest/farthest zone in the array (zone 1 and zone 5), and the second spacing ratio for each zone 486 refers to the zone to the center zone of the array (zone 3 ) interval. However, it should be noted that in alternative embodiments, the spacing ratio per zone may refer to any zone in the array.

Using either of the spacing ratios for each zone 484 and 486, the relative spacing between channels is determined by assigning a reference spacing value to a reference zone that has a spacing ratio of 1. The spacing ratio for each associated zone is then used as a multiplier for the reference spacing value to determine the spacing values for all other zones in the array individually. The reference spacing value is selected using techniques known in the art, wherein the maximum spacing value between energy directors in an array is approximately in the range of 0.75 cm to 2.00 cm, although the embodiments are not limited thereto.

Alternative embodiments of the tissue coagulation system include different numbers of energy directors and thus also have different numbers of channels in the energy director guides. For example, an alternate embodiment includes an energy director guide having a series of 8 channels that can accept alternate polarity energy directors. As noted above, channel spacing is also determined in this alternative embodiment using resistor network model simulations, but is not limited thereto.

Figure 5A shows a resistive network model 500 of an energy director configuration comprising 8 energy directors in another embodiment. Extrapolating from the embodiment of Figure 2, the energy director guide in this example includes 8 channels, each of which receives an energy director. Each of the 8 bipolar energy directors is represented by one of nodes 1-8, where each node is assigned an alternate polarity. Model 500 includes a number of resistors R1-R44 coupled between nodes 1-8 and current source 502 in various configurations, as described below. The current source 502 can be chosen arbitrarily to produce a current of 1 amp, but the model is not limited to this.

With respect to FIG. 5A , resistor R1 models power dissipation as a result of current flowing between nodes 1 and 2 . Likewise, resistors R2, R3, R4, R5, R6 and R7 simulate the power consumption as a result of the current flow between the nodes defining each of regions 2-7, respectively. A series combination of resistors R8, R9 and R10 is coupled between nodes 1 and 4 and simulates power dissipation across regions 1, 2 and 3 as a result of current flowing between nodes 1 and 4. A series combination of resistors R11, R12, R13, R14 and R15 is coupled between nodes 1 and 6 and simulates power dissipation across regions 1, 2, 3, 4 and 5 as a result of current flowing between nodes 1 and 6.

Next, a series combination of resistors R16, R17 and R18 is coupled between nodes 3 and 6 and simulates power dissipation across regions 3, 4 and 5 as a result of current flowing between nodes 3 and 6. A series combination of resistors R19, R20, R21, R22 and R23 is coupled between nodes 3 and 8 and simulates power dissipation across regions 3, 4, 5, 6 and 7 as a result of current flowing between nodes 3 and 8. A series combination of resistors R24, R25 and R26 is coupled between nodes 2 and 5 and simulates power dissipation across regions 2, 3 and 4 as a result of current flowing between nodes 2 and 5. The series combination of resistors R27, R28 and R29 is coupled between nodes 5 and 8 and simulates power dissipation across regions 5, 6 and 7 as a result of current flowing between nodes 5 and 8.

Additionally, a series combination of resistors R30, R31 and R32 is coupled between nodes 4 and 7 to simulate power dissipation across regions 4, 5 and 6 as a result of current flowing between nodes 4 and 7. A series combination of resistors R33, R34, R35, R36 and R37 is coupled between nodes 2 and 7 and simulates power dissipation across regions 2, 3, 4, 5 and 6 as a result of current flowing between nodes 2 and 7. Finally, the series combination of resistors R38, R39, R40, R41, R42, R43, and R44 is coupled between nodes 1 and 8 and simulates the spanning regions 1, 2, 3, 4, 5, 6 and 7 power consumption. FIG. 5B shows a table 550 including power consumption values in the embodiment of FIG. 5A that correspond to energy director configurations that provide balanced energy.

Figure 5C shows a table 580 including power consumption information 582 and interval information 584 and 586 in the embodiment of Figure 5A, the information corresponding to an energy controller configuration providing balanced energy. The power consumption table 580 includes the total power consumption 582 for each zone of the resistor network model 500 . As noted above, the balanced energy director configuration uses non-uniform channel spacing in the energy director guides to account for the effect of electromagnetic coupling. The total power consumption across zones 1-7 is approximately 563mW, 565mW, 564mW, 567mW, 564mW, 565mW and 563mW, respectively. Therefore, the power consumption or distribution across the intervals is approximately uniform.

The embodiments described above with reference to Figures 2, 3, 4 and 5 provide a substantially uniform distribution of power across the tissue regions of the target tissue volume. However, because power is proportional to the product of voltage and current, alternative embodiments of the energy director array are configured to provide a substantially uniform current density in the target tissue volume. Likewise, the tissue coagulation systems of various alternative embodiments employ substantially uniform current densities to create an avascular volume of coagulated tissue. Energy director guide channel spacing to provide uniform current density is determined using a resistive network model as described above, but is not limited thereto.

Guide channel spacing that provides relatively uniform current density is generated using a resistive network model, but is not limited thereto. FIG. 6A shows a resistive network model 600 of an energy controller configuration including six bipolar energy directors in the alternate embodiment of FIGS. 2 and 3. Each of the six bipolar energy directors is represented by nodes 1- A representation of 6 where each node is assigned an alternate polarity. As described above with respect to FIG. 4A , modulo model 600 includes a number of resistors R1 - R19 coupled between nodes 1 - 6 and current source 602 in various configurations. The relative power consumption between different regions is proportional to the current density in the relevant tissue regions. Current source 602 was arbitrarily selected to produce a current of 750 milliamps ("mA"), although the model is not limited thereto. Figure 6B shows a table 650 that includes power consumption information for the embodiment of Figure 6A that corresponds to an energy controller configuration that provides balanced energy.

Figure 6C is a table 680 including current density and spacing information corresponding to an energy director configuration to provide balanced energy in the embodiment of Figure 6A. The table 680 includes the current density per region 682 for the resistive network model 600 (current density/region 682 ). As noted above, the balanced energy director configuration uses non-uniform channel spacing in the energy director guides to account for the effect of electromagnetic coupling. In determining the current density/area 682, the resistance values of the areas in the array are iteratively varied until the current densities/area 682 are approximately equal; the channel spacing information is proportional to, and derived from, the final resistance value providing an approximately uniform current density. The current densities/zone spanning Zones 1-5 are approximately, but not limited to, 15.85mA/interval, 15.8446mA/interval, 15.80769mA/interval, 15.8446mA/interval, and 15.85mA/interval, respectively. Thus, the current density is approximately uniform between the zones.

Using current density per zone 682, a spacing ratio per zone 684 and 686 results. In one embodiment, 2 different spacing ratios per zone 684 and 686 are created, although the embodiment is not limited thereto. The first spacing ratio for each zone 684 refers to the spacing of the zone to the closest/furthest zone in the array (zone 1 and zone 5), and the second spacing ratio for each zone 686 refers to the zone to the center zone of the array (zone 3 ) interval. However, it should be noted that in alternative embodiments, the spacing ratio per zone may refer to any zone in the array.

Using either of the spacing ratios for each zone 684 and 686, the relative spacing between channels is determined by assigning a reference spacing value to a reference zone that has a spacing ratio of 1. The spacing ratio for each associated zone is then used as a multiplier for the reference spacing value to determine the spacing values for all other zones in the array individually. The reference interval value is selected using techniques well known in the art.

Alternative embodiments of the tissue coagulation system include different numbers of energy directors and thus also have different numbers of channels in the energy director guides. As noted above, the channel spacing for these alternative embodiments can also be determined using a resistive network model, but is not limited thereto.

Figure 7 is a side, end and top view of an energy director guide 7000 and two or more pairs of bipolar energy directors 7001-7006 in another embodiment. The energy director guide 7000 supports an energy director configuration that provides substantially uniform energy distribution and/or current density, and thereby provides a more uniform temperature through the target tissue volume. The energy director guide 7000 configures the energy directors 7001-7006 in a linear arrangement, and the energy directors 7001-7006 alternate polarity, an example polarity is shown here, but the embodiment is not limited thereto. Although three pairs of energy directors 7001-7002, 7003-7004, 7005-7006 are shown, embodiments are not limited thereto.

With relatively small spacing within a pair of energy director pairs and relatively large spacing between pairs of energy directors (also referred to as distinct pairs), the energy director guide 7000 generally supports uniform energy distribution in the target tissue. distributed. For example, a first spacing is employed between each pair of energy directors 7001 and 7002, 7003 and 7004, and 7005 and 7006, while a second spacing is employed between energy directors 7002 and 7003, 7004 and 7005. In one embodiment, the inter-pair spacing of energy directors is approximately 1.5 to 2 times the spacing within energy director pairs, although the embodiment is not limited thereto.

The configuration supported by the energy director guide 7000 results in highly favorable electrical pathways between different pairs of energy directors. The favorable electrical pathways result in most of the electrical energy flowing between different pairs of energy directors (in this example, between energy director pairs 7001/7002, 7003/7004, and 7005/7006), thus creating Blood coagulation between tissues. Once interpair coagulation occurs, the impedance in the tissue begins to rise. As the impedance increases, alternate paths to energy directors of opposite polarity in adjacent different pairs become increasingly advantageous (in this example, between energy directors 7002/7003 and 7004/7005). As time continues, the inter-pair impedance (7002/7003 and 7004/7005) continues to increase, resulting in the establishment of new pairs (7002/7003 and 7004/7005). This process continues until all coagulation is complete.

In another embodiment, the energy director guide can be reconfigured to support numerous energy director configurations. For example, the energy director guides may include channels that are movable between a number of predetermined positions of the energy director guides such that the channels are configured in a first set of predetermined positions along the guides to support the six energy directors described above configurations, and channels are configured in a second set of predetermined locations along the guides to support the eight energy director configurations described above. With this embodiment, a user can support many different energy director configurations with a single energy director guide.

Referring again to FIG. 1 , in one embodiment the energy director guides independently couple each energy director to the generator through the energy director guides. In addition, the energy director guide independently secures the position of each energy director in the target tissue.

With regard to the electrical coupling of the energy director to the generator, in one embodiment the energy director guide is directly coupled, while in other embodiments it is indirectly coupled. Figure 8 is a side view of an energy director guide 102 employing direct coupling in one embodiment. Each channel 202 and 204 of the guide 102 includes one or more contacts 702 and 704 that directly couple the conductors 706 and 708 of the energy line 799 from the generator (not shown) to the respective energy directors 104a and 104b . For example, when a bipolar energy director is employed, a first conductor 706 carrying a signal of a first polarity is coupled to the first energy director 104a through a first contact 702 . Likewise, a second conductor 708 carrying a signal of a second polarity is coupled to the second energy director 104b through the second contact 704 . The contacts in one embodiment are made of materials having good elastic and abrasive properties including, for example, stainless steel and beryllium copper. In addition, the contact in another embodiment can also secure or help secure the position of the energy director, but is not limited thereto.

FIG. 9 is a schematic diagram of a circuit board 800 for an energy director guide in the embodiment of FIG. 2 . Through conducting traces 802 and 804, circuit board 800 couples power signals from power sources with appropriate polarity directly to corresponding channels, and to corresponding energy directors. In circuit board 800 of one embodiment employing alternating polarity, in the middle of the energy directors of channels 202, 206, and 210, first conductive trace 802 carries an electrical signal having a first polarity, eg, positive. Intermediate to the energy directors of channels 204, 208, and 212, a second conductive trace 804 carries an electrical signal having a second polarity, such as negative, although embodiments are not limited thereto.

In one embodiment using indirect coupling, a coil of conductive material insulated along its length is wound such that it forms a magnetic field around the conductive energy director, thereby inducing a current in the energy director. Figure 10 is a side view of a guide 102 employing indirect coupling in one embodiment. Each channel 202 and 204 of the guide 102 includes a coil or winding of conductive material 902 and 904 that indirectly couples conductors 912 and 914 in a power source (not shown) energy line 999 to a respective energy director 104a and 104b.

As noted above, the energy director guides of one embodiment enable independent control of the position of the respective energy directors. Figure 11 shows a guide 102 provided in one embodiment for independently controlling the deployment or insertion depth of each energy director 1002. The guides 102 provide independent control over the independently variable depth of insertion of each energy director 1002 into the target tissue. The approximate range of energy director deployment depth is 1 cm to 10 cm, but is not limited thereto. For example, in one embodiment the energy director is deployed to a depth of about 4 centimeters, while in another embodiment the energy director is deployed to a depth of about 6 centimeters. Additionally, the energy director of one embodiment includes indicia corresponding to the depth of deployment for assisting insertion of the energy director into the target tissue.

Insertion of the energy director 1002 may be performed alone or suitably concurrently with the procedure. Likewise, each energy director 1002 can be inserted at a different depth into the target tissue, thus allowing the physician or clinician to avoid applying RF energy to critical anatomical structures. This is especially valuable since there are often critical anatomical structures into which the energy director 1002 should not be inserted. In addition, independent control of the insertion depth of each energy director 1002 enables the use of various imaging methods, such as ultrasound stenography, computed tomography ("CT"), and magnetic Resonance Imaging ("MRI").

Independent control of insertion depth also supports heating uniformity as follows. Extensive local blood flow can lead to higher local heat loss. These uneven heat losses can lead to uneven or incomplete coagulation. The tissue coagulation system of one embodiment counteracts this effect by enabling regulation of the amount (eg, penetration depth) of energy lines deployed around the area. Accordingly, the energy distribution can be changed to compensate for the additional loss.

Changes in energy distribution can be achieved by reducing the penetration depth of energy directors of the same polarity in areas of tissue adjacent to tissue containing greater local blood flow. This adjustment of penetration depth results in an increased impedance path through these adjacent energy directors, thereby shifting energy into lower impedance paths that have become encompassed by regions of greater blood flow. In the case of larger vessels, once they have coagulated (as measured, for example, with ultrasound Doppler and/or Doppler flowmeters), the energy line configuration can return to a uniform volume as described above.

Once inserted into the target tissue, the components of the energy director guide will apply sufficient force to the corresponding energy directors to secure them in the target tissue so that the natural movement of the body does not push the energy directors out. The energy director guide assembly exerts a retaining force on the energy director generally in the range of, but not limited to, 0.2 pounds force ("lbf") to 2 lbf.

Figure 12 illustrates the operation of the tissue coagulation system in the embodiment of Figure 2 to generate an avascular volume of tissue. Typically a coagulation procedure begins with positioning energy director 1104 at a first depth in target tissue 199 . Depths shown are examples only and are not limiting. Likewise, the first depth at which the energy director 1104 is placed is not limited to a particular depth, other than the length of the energy director 1104 used in a particular procedure or the presence of a particular anatomy in the target tissue. After the energy director is positioned, the user applies power to the positioned energy director 1104, thereby resecting a corresponding volume 1110 in the particular target tissue.

In another example of operation, the tissue coagulation system may be used to progressively ablate volumes of the target tissue as the energy director 1104 progresses deeper into the target tissue. FIG. 13 illustrates the operation of the tissue coagulation system to generate an avascular volume of tissue in an alternative embodiment to FIG. 12 . Referring to FIG. 13 , and after coagulation of tissue volume 1110 associated with the first depth of energy director 1104 ( FIG. 12 ), energy director 1104 is advanced further into target tissue 199 at a second depth. After this depth, the user couples the power to the energy controller 1104, thereby resecting a corresponding incremental volume 1210 in the particular target tissue. Proceeding deeper into the energy director 1104 until the entire desired volume of tissue is avascular or nearly avascular. The shape and size of the coagulation volumes 1110 and 1210 can be controlled by, for example, the configuration of the electrode cluster, the geometry of the exposed energy director tip, the magnitude of the applied power, the duration of the applied power, and electrode cooling.

The tissue coagulation systems and related methods and procedures provided herein are particularly useful for controlling and optimizing several key parameters of tissue coagulation procedures, including energy density, thermal load of surrounding tissue, and electrical resistance of the tissue. Tissue coagulation procedures include thermal coagulation necrosis of soft tissues as an aid during tissue resection. Provided below are methods of applying power or energy in a balanced mode using the described tissue coagulation system to produce a uniform cross section of coagulated tissue, where the power can be in any form that results in heating of the tissue. The balanced mode of power application is to deliver energy in a manner that produces a fairly uniform volume of coagulated tissue, resulting in hemostasis. This is achieved by creating a fairly uniform temperature increase in the target tissue.

The tissue coagulation system of one embodiment produces a uniform volume, generally rectangular volume, of coagulated tissue, although the embodiment is not so limited. For example, the rectangular volume may have a width approximately in the range of 0.5 cm to 1 cm, but is not limited thereto. The rectangular volume overcomes the problems in prior art tissue coagulation systems which attempt to use a series of spherical coagulation volumes to create a shaped coagulation surface/volume.

Due to their geometry, attempts to use a series of overlapping spheres to form a rectangular coagulation surface will result in a very irregular target tissue surface. This irregular surface causes problems when attempting to resect within this irregular plane or surface of resected tissue created by the series of spheres. If the sphere of resected tissue is large enough to completely encompass the desired rectangular face of resected tissue, then too much tissue will be resected. This excess of dead tissue can then cause significant and potentially life-threatening problems for the patient. On the other hand, if the maximum diameter of the thrombus spheroid is within the desired rectangular plane, a significant portion of hemostasis is lost due to the large amount of unresected tissue remaining at the uneven edges of the overlapping spheroids. In this case, the cause of clotting is greatly reduced or eliminated. Furthermore, the use of monopolar energy to generate coagulation spheroids results in an undefined and limited coagulation surface due to the inherent nature of monopolar energy.

The typical method of tissue coagulation by applying a uniform amount of power to a uniform tissue volume is not optimal because it does not result in a uniform increase in tissue temperature. The problems inherent in typical systems and methods involve several aspects. First, thermal effects cannot be realized when the energy density is too low. Likewise, thermal effects cannot be achieved when the thermal load on the surrounding tissue is too great. Also, the low tissue resistance makes it difficult to heat because the power dissipated is proportional to the tissue resistance. Very low or very high impedances can also make it difficult for some power sources to deliver the required energy.

In a typical configuration known in the art, for example, several energy conduits may be placed at even intervals in the target tissue. When an energy source, such as a radio frequency (RF) current, is applied uniformly to this arrangement of energy lines in a bipolar pattern, the current from the outer energy lines is distributed inwardly into the opposite polarity energy lines. Similarly, currents from other energy conduits also flow into energy conduits of opposite polarity. It can thus be seen and demonstrated that this configuration leads to an uneven superimposition of the currents. Thus such uniform placement of energy conduits with a uniform amount of energy delivery will not result in uniform current distribution (or current density), uniform energy dissipation, or uniform increase in temperature within the tissue.

However, in one embodiment the energy conduit configuration and method provided by the tissue coagulation system provides a more uniform temperature of the target tissue, thereby reducing and/or eliminating many of these problems. Figure 14 is a flowchart 1400 of the operation of the tissue coagulation system, in one embodiment. In block 1402, in operation, and based on clinical conditions and requirements, the user selects the appropriate electrode configuration. Such selection includes, for example, determining factors related to: (i) the number of electrodes in the cluster; (ii) the relative geometry, individual size, and electrode tip exposure; (iii) the geometry of the target tissue region and identifying any tissue regions to avoid and (iv) the use of cooled or uncooled electrodes. Additionally, selection may include processing image scan data from CT scans, MRI, ultrasound, and/or other types of scanning equipment for determining target volumes, such as tumor locations within the patient's body, and desired methods, and placement of electrodes, size and number.

In one embodiment the positioning of the electrodes is pre-planned, eg using a workstation, and the heating isotherms and coagulation volume and time course of coagulation are determined. Based on historical or empirical information, the user can determine the desired power to be delivered to the tissue, the temperature (measured by the electrodes or elsewhere in the tissue via an integrated temperature sensor in the energy director or a satellite temperature sensing electrode), the desired duration of heating Time, and impedance characterization to determine energy application time parameters and controls to avoid charring and other undesired effects.

Additionally, selection of electrode configuration in one embodiment includes determining electrode size based on the target organ. For example, the user can estimate the lateral dimensions of the target organ. Using the estimated lateral dimensions, the user individually or in groups sizes the electrodes so that when the electrodes are fully inserted into the target organ, the electrodes do not extend beyond the target organ.

In block 1404, after construction and planning, the user positions the energy director guide and inserts the electrodes into the target tissue. The electrodes may be placed in body tissue individually or together as described herein. During placement of the electrodes, real-time imaging such as CT, MRI and/or ultrasound may be used to determine their proper location in the target volume of tissue. The user inserts the electrodes to the desired depth. In addition, if the electrode uses a coolant, the user can properly use the coolant.

During some procedures involving the tissue coagulation system, the user separates the target organ from one or more adjacent organs, although embodiments are not so limited. This is done to prevent the electrodes from sticking to adjacent organs when inserted into the target organ. Alternatively, the user may place a barrier between the target organ and any adjacent organs to protect the adjacent organs from electrode puncture.

In block 1406, the user couples or applies power from the generator to the energy director guide and electrodes. Alternatively, power can be coupled directly to the electrodes. While power is described in this example, various alternative embodiments may use current, voltage, impedance, temperature, time, and/or any combination of these parameters instead of power as the control parameter to control the tissue coagulation process. Power may be coupled to all electrodes together or sequentially in a predetermined order, tailored to the treatment procedure and/or target tissue type. Likewise, the depth of insertion of the electrodes and the amount of power coupled to the electrodes may vary depending on the treatment procedure and/or target tissue type.

As described in detail below, in any of a number of procedures, the application of power can be controlled automatically and/or manually. When automatic control is used, control is based on one or more algorithms or controllers integrated into the generator system itself or by one or more distributed algorithms and/or controllers coupled between components of the tissue coagulation system process. Additionally, the application of power to the electrodes can be controlled in response to at least one parameter including time, temperature, and/or other known feedback parameters related to the coagulation process.

At block 1408, thermal coagulation of the tissue is monitored using feedback parameters appropriate to the equipment and procedure used. Power is coupled to the energy director guide/electrodes at block 1406 resulting in the creation of a coagulated tissue plane in the target tissue at block 1410 . In one embodiment, predetermined parameters and thresholds appropriate to the device and procedure are used to determine when a coagulated tissue plane has occurred. In block 1412, the user repeats portions of the procedure depending on the target tissue until a clotted tissue surface of the appropriate size and shape is produced.

In one embodiment, operation of the tissue coagulation system involves the use of a temperature feedback system in which temperature is measured at one or more locations within the tissue and the delivered power is varied or varied (i.e., increased, decreased, or held constant) to maintain energy delivery the correct level. With this method, the target tissue is divided into different quadrants or zones, and the power delivery is individually varied on a zone-by-zone basis using temperature feedback information. When the temperature of a given zone increases significantly beyond the other zones, the power delivery to that zone is reduced sufficiently to maintain equilibrium with the other zones or to maintain a predetermined target temperature. Conversely, based on temperature feedback information, if a zone is cooler than other zones of the target tissue, the power delivered to that zone is increased to achieve an equal or predetermined target temperature with the other zones.

A predetermined ramp rate can also be used to bring the temperature of an individual zone of target tissue to a level comparable to the temperature induced by other zones in the target tissue. For example, if the predetermined rate of temperature increase is approximately in the range of 35 to 40 degrees Celsius/minute, then power is applied at the initial rate and the temperature increase is evaluated. If, over time, the temperature of that individual zone in the target tissue is lower, then the power to that zone is increased. If the temperature of the tissue in a zone of the target tissue increases beyond a predetermined rate, resulting in a higher temperature, the power delivered to that zone is reduced. This method has the benefit of allowing the selection of predetermined rates for specific tissue types and conditions. In addition, it is also easier to account for local variations in heat loss due to various factors such as blood flow. To achieve a more even distribution, the number of partitions per unit of target tissue can be increased. In addition, a more uniform distribution can also be achieved by using a smaller predetermined temperature range.

In one embodiment the operation of the tissue coagulation system also includes using a change in the amount of tissue to which the amount of power is applied. In this method, the natural flow and overlap of delivered power is accounted for by increasing or decreasing the spacing between energy lines. This effectively alters the energy pathways, increasing or decreasing relative resistance and energy flow. This results in a balanced power dissipation, and thus uniform heating, within the target tissue. As mentioned above, the spacing of energy channels in tissue can be simulated by electrical circuits. The model assigns a resistance value to the tissue between the energy conduits that is proportional to the distance between the energy conduits. Analysis of this circuit allows adjustment of the resistance or distance between energy conduits so that a uniform amount of energy is dissipated within the tissue to provide a fairly uniform temperature increase, as described above with reference to FIGS. 4 , 5 and 6 .

In general, a procedure using one embodiment of the tissue coagulation system begins with the selection of an energy circuit of sufficiently conductive material depending on the power source. The energy conduit configuration should have sufficient interface between the energy conduit and the target tissue to accommodate the desired rate of power transfer, and thus temperature increase, since there is usually a point of highest energy density around the energy conduit.

An insufficient interface between the energy conduit and the target tissue to deliver the amount of power can lead to a rapid increase in dehydration and charring or charring of the tissue surrounding the energy conduit, with the result that tends to inhibit or stop communication between the tissue and the energy conduit. energy transfer. Various other methods can also be used to help alleviate this limitation by reducing the temperature or the rate of temperature rise around the energy line. These mitigation methods include cooling the energy line or the tissue surrounding the energy line, and/or adding an agent around the energy line to reduce the energy impedance between the energy line and the target tissue, resulting in power loss around the energy line. Consumption is reduced.

After the energy circuit is selected, the energy circuit is placed in the construct resulting in a substantially uniform temperature increase sufficient to cause coagulation of the target tissue. The number and size of energy circuits used are a function of several factors including, for example, the available energy delivered from the power source, the length of time the energy is delivered, the desired shape of the resulting clotted tissue, the amount of heat loss within the tissue, and tissue charring sensitivity etc. Once the electrodes are placed, the operator can begin delivering energy to the target tissue.

When using a power source based on tissue resistive heating, such as when using RF current, a lower amount of power is delivered during the initial phase of heating, although embodiments are not so limited. The initial delivered energy ranges roughly between 10 and 100 watts, depending on the depth of electrode insertion, but is not limited thereto, as the power value depends on the amount of interfacial surface area between the energy conduit and tissue (for relatively small contact surface area, the amount of power can be significantly reduced; likewise, the amount of power can be increased for relatively large contact surface areas). This ruptures the cell membranes in the tissue and around the energy conduits and releases conductive interstitial fluid. The release of the conductive interstitial fluid results in lower impedance around the energy conduits and supports subsequent higher amounts of power transfer. This power increase allows for greater power delivery and reduces processing time. In addition, this greater amount of power can coagulate larger blood vessels.

Upon initial power delivery, the temperature of the target tissue begins to increase. Factors such as local blood flow and dilatory effects in the target tissue region can lead to increased heat loss from the target tissue, thereby reducing the temperature rise in the tissue immediately adjacent to the region. This condition is counteracted in operation by increasing the amount of power delivered to areas containing greater local blood flow by increasing the energy in the target tissue passing through the affected area.

Because energy in a particular area can be increased by reducing the number of energy lines of the same polarity available in adjacent areas, partial withdrawal of adjacent energy lines of the same polarity, for example, can reduce the tissue-engaging surface area of these energy lines , thereby redirecting more energy into areas of higher local blood flow. Subsequently, more energy is delivered to areas containing higher local blood flow which then compensates for the additional heat loss. Once the unbalanced blood flow is removed, for example by coagulating individual large blood vessels, the energy conduits in the array are again positioned with approximately uniform exposure.

Completion of the coagulation process in the target tissue is detected in a number of ways, including using tissue temperature and/or tissue impedance. When tissue temperature is used, tissue temperature can be measured in a number of ways. One way of measuring tissue temperature includes measuring the temperature in or around the energy circuit. This measurement technique is easy to implement, since it uses an energy line to house or transmit at least one temperature sensor without requiring additional materials.

However, temperature measurements by sensors in the energy line typically measure temperatures at or near locations of highest energy density; this tends to provide higher temperatures than measurements in target tissue in the immediate vicinity of the energy line. This problem can be mitigated to some extent by reducing the high energy density around the energy line by using a larger interface between the energy line and the target tissue. This problem can also be mitigated by using a bipolar energy line configuration if RF energy is used. Because the energy conduits are localized to the target tissue, the bipolar configuration maintains more "line of sight" energy transmission, resulting in higher energy density throughout the target tissue. This is in contrast to a monopolar scheme, where a first polarity is used for energy conduits close to the target tissue and a second polarity (opposite) is located further away from the target tissue; in this monopolar configuration, energy tends to flow from The energy conduits spread outwards in all directions, ultimately seeking the path with the lowest impedance for transmission of the opposite polarity at a distance.

Another method of measuring tissue temperature involves positioning the temperature sensor within the target tissue, but away from the energy lines. This supports evaluating the temperature in regions of relatively lower energy density, yielding a lower or "worse case" temperature indication. Any effects of abnormal heat loss, such as heat loss from large blood vessels, can thus be noted. Measurement of tissue temperature remote from the energy line includes using a fixed location for temperature measurement remote from the energy line, or moving the temperature probe during the procedure to measure temperature at various locations remote from the energy line. Once the temperature in the target tissue reaches a temperature above the tissue coagulation temperature (often at or above 70 degrees Celsius), energy delivery is stopped.

Another method of determining the completion of the coagulation process involves measuring the electrical resistance within the target tissue. When coagulation energy is applied to tissue, the electrical resistance between the energy conduits and the tissue typically decreases due to the release of conductive interstitial fluid from the tissue. After this resistance decreases, the resistance stabilizes and is maintained there as the tissue temperature increases. As energy continues to be delivered to tissue after coagulation has occurred, a higher degree of tissue dehydration will occur. This dehydration manifests itself as a slow increase in the impedance between the energy circuits. A small sustained rise in tissue impedance thus indicates the completion of tissue coagulation and a process of higher water loss in the target tissue. Further application of energy resulted in a large and rapid increase in impedance, indicating an undesirable transition from dehydration to charring or charring. Therefore, energy delivery was stopped once a steady increase in impedance was observed. It is assumed that the initial energy delivery to the target tissue is low enough to avoid premature tissue charring around the energy line.

Another alternative method of determining the completion of the coagulation process involves the use of temperature and tissue impedance measurement/measurement components. The temperature and tissue impedance measurement components are located in a single feedback system, although embodiments are not limited thereto.

Once coagulation in the target tissue is complete, the energy line is removed. The energy circuit is relocated to another area of the target tissue, as described here, and the above method is repeated as necessary to create a larger surface of coagulated tissue. If the coagulation method uses bipolar RF energy, one of the outermost energy lines should be adjacent to the coagulation zone created by the previous coagulation surface, but embodiments are not limited thereto. Once the full length of the clotted coagulation surface is complete, tissue resection is performed through the coagulation surface.

Alternative Embodiments Any number of energy director guides/electrodes may be employed simultaneously in a procedure to create a coagulated tissue volume of shape and size appropriate for the treatment procedure. Based on the tissue coagulation system described herein, many alternatives will occur to those of ordinary skill in the art.

As noted above, energy application in one embodiment is controlled automatically and/or manually in many procedures. A first type of program uses a predetermined pattern of energy delivery according to a time schedule. A second type of procedure varies the application of energy to a target tissue volume in accordance with temperature information or feedback parameters of the tissue. A third type of procedure varies the application of energy to the target tissue volume in accordance with tissue impedance information or feedback parameters in conjunction with elapsed time. A fourth type of procedure varies the application of energy to a target tissue volume in accordance with impedance information or feedback parameters of the tissue. A fifth type of procedure varies the application of energy to the target tissue volume in accordance with temperature and impedance information or feedback parameters of the tissue. Each program type is described in detail below.

A first type of program employs a predetermined pattern of energy delivery according to a time schedule. A program under the first program type instructs the user to select a predetermined power setting based on the depth of insertion of one or more electrodes into the target tissue, and then directs the application of energy for a predetermined time. The program guides selection of a 15 watt (W) power setting for a 1 centimeter ("cm") electrode insertion depth, a 30 W power setting for a 2 cm electrode insertion depth, a 45 W power setting for a 3 cm electrode insertion depth, and a 60 W power setting for a 4 cm electrode insertion depth , 75W power setting corresponds to 5cm electrode insertion depth, and 85W power setting corresponds to 6cm electrode insertion depth. The program directed to apply power for no more than about 3 minutes after selecting a power setting appropriate for the depth of electrode insertion. At the end of the 3 minute period, the user fully withdraws the electrodes and removes the tissue coagulation device. The process is repeated as necessary to produce the desired volume of resected tissue. For example, the use of this energy delivery mode can be combined with the InLine ^™ radio frequency coagulation device described above and the Radio Therapeutics Corporation (Boston Scientific) generator (Models RF 2000 ^™ or RF 3000 ^™ equipped with cable adapter recorder number 03-0504-U), but It is not limited to this.

Another program under the first program type instructs the user to select a predetermined power value based on a time schedule and a depth of insertion of one or more electrodes into the target tissue. For example, for a 1 centimeter ("cm") electrode insertion depth, the program instructs to apply 10 watts for 90 seconds ("secs"), followed immediately by 15 watts for 60 seconds, followed immediately by 20 watts for 30 seconds. When using a 2-cm electrode insertion depth, the program instructs to apply 25 watts for 90 seconds, followed by an immediate application of 30 watts for 60 seconds, followed by an immediate application of 35 watts for 30 seconds. When using a 3-cm electrode insertion depth, the program instructs to apply 40 watts for 90 seconds, followed by an immediate application of 45 watts for 60 seconds, followed by an immediate application of 50 watts for 30 seconds. When using a 4-cm electrode insertion depth, the program instructs to apply 55 watts for 90 seconds, followed by an immediate application of 60 watts for 60 seconds, followed by an immediate application of 65 watts for 30 seconds. When using a 5-cm electrode insertion depth, the program instructs to apply 70 watts for 90 seconds, then immediately 75 watts for 60 seconds, and then immediately 80 watts for 30 seconds. When a 6-cm electrode insertion depth was used, the program directed the application of 80 watts for 90 seconds, followed by an immediate application of 85 watts for 60 seconds, followed by an immediate application of 90 watts for 30 seconds. Upon completion of 3 power cycles appropriate to the insertion depth, the user fully withdraws the electrodes and removes the tissue coagulation device. This process is repeated as necessary to produce the desired volume of resected tissue.

系统RF发生器(Model 1500，配备有电缆适配器记录仪编号03-0501-U或Model 1500X，配备有电缆适配器记录仪编号03-0502-U)，但并不局限于此。使用这种能量传递模式也可组合

(Tyco Healthcare)Cool-tip^TM射频发生器(配备有电缆适配器记录仪编号03-0503-U)。A further program under the first program type instructs the user to select a predetermined power value based on a time schedule and insertion depth of one or more electrodes into the target tissue. For example, for a 1 cm electrode insertion depth, the program instructs to apply 13 watts for 90 seconds ("secs"), followed immediately by 15 watts for 60 seconds, followed immediately by 17 watts for 30 seconds. When using a 2-cm electrode insertion depth, the program instructs to apply 27 watts for 90 seconds, followed by an immediate application of 30 watts for 60 seconds, followed by an immediate application of 33 watts for 30 seconds. When using a 3-cm electrode insertion depth, the program instructs to apply 41 watts for 90 seconds, followed by an immediate application of 45 watts for 60 seconds, followed by an immediate application of 50 watts for 30 seconds. When a 4-cm electrode insertion depth was used, the program directed the application of 54 watts for 90 seconds, followed by an immediate application of 60 watts for 60 seconds, followed by an immediate application of 66 watts for 30 seconds. When a 5-cm electrode insertion depth was used, the program directed the application of 68 watts for 90 seconds, followed by an immediate application of 75 watts for 60 seconds, followed by an immediate application of 83 watts for 30 seconds. When using a 6-cm electrode insertion depth, the program instructs to apply 77 watts for 90 seconds, followed by an immediate application of 85 watts for 60 seconds, followed by an immediate application of 94 watts for 30 seconds. Upon completion of 3 power cycles appropriate to the insertion depth, the user fully withdraws the electrodes and removes the tissue coagulation device. This process is repeated as necessary to produce the desired volume of resected tissue. For example, using this mode of energy delivery can be combined with the Inline ^TM radio frequency coagulation device described above and

System RF Generator (Model 1500 with Cable Adapter Recorder No. 03-0501-U or Model 1500X with Cable Adapter Recorder No. 03-0502-U), but not limited to. Using this mode of energy transfer can also be combined

(Tyco Healthcare) Cool-tip ^TM radio frequency generator (equipped with cable adapter recorder number 03-0503-U).

These programs, in which the user applies a predetermined amount of power according to a time schedule and electrode insertion depth, are effective for coagulation of many types of tissue. Phased power delivery results in a lower amount of power being delivered at the beginning of the procedure, where the lesser amount of power coagulates tissue with lower blood flow, such as cirrhotic tissue, earlier in the procedure without the flashing effect and adipose tissue, the rapid action can stop the coagulation process. Furthermore, delivery of greater amounts of power later in the procedure allows complete coagulation of tissues with higher blood flow without unduly extending the overall duration of the procedure.

A second type of procedure varies the application of energy to a target tissue volume based on tissue temperature information or feedback parameters. Such procedures include varying energy and/or energy application times based on temperature information received from at least one temperature sensor in the target tissue. The applied energy and/or energy application time is controlled according to predetermined temperature parameters appropriate to the target tissue type/procedure to prevent delivery of excess energy and thus prevent overheating and charring of the target tissue.

Figure 15 is a flowchart 1500 for controlling tissue coagulation based on temperature parameters, in one embodiment. In block 1502, after placing the electrodes in the target tissue, the user increases the energy delivered to the target tissue by an amount P ₁ , where P ₁ is in the approximate range of 0.1 W/sec to 10 W/sec. In block 1504, it is determined whether the rate of temperature change in the target tissue is less than or equal to 1 _min , where 1 _min has an approximate range of 0.1 degrees Celsius/sec to 5 degrees Celsius/sec. In block 1506, when the rate of temperature change is less than 1 _min , the power delivered to the target tissue is increased and operations in block 1504 are continued.

In block 1508, when the temperature change rate is higher than I _min , it is necessary to measure the temperature change rate in the target tissue to determine whether it is higher than or equal to I _max , wherein I _min is approximately 5 degrees Celsius/sec. In block 1510 , when the rate of temperature change is greater than I _max , the energy delivered to the target tissue is reduced and operations continue in block 1504 .

In block 1512, when the rate of temperature change in the target tissue is within the range defined by _Imin and _Imax , it is determined whether the temperature in the target tissue is above _Tmax , where _Tmax is approximately in the range of 85 to 115 degrees Celsius. In block 1514 , when the temperature of the target tissue is above T _max , the power delivered to the target tissue is reduced and operations in block 1504 continue.

In block 1516, when the rate of temperature change in the target tissue is within the range defined by _Imin and _Imax , and the temperature of the target tissue is below _Tmax , the power delivered to the target tissue is increased by an amount _P2 , where _P2 The approximate range is 0.1W/sec to 10W/sec. At block 1518, operation continues with determining whether the time taken to apply power to the target tissue exceeds _Dmax , where _Dmax is a predetermined amount of time greater than 1 minute. In block 1520, when the elapsed time exceeds D _max , the power application to the target tissue is terminated; otherwise, the operation continues with block 1504 as described above.

As noted above, the example procedure for controlling tissue coagulation based on temperature parameters uses the following parameter values: P ₁ is approximately 2 W/sec, I _min is approximately 2 °C/sec; I _max is approximately 5 °C/sec; T _max is approximately 105 Celsius; P ₂ about 4W/sec; and D _max about 3 minutes. These parameters are examples only and do not limit the embodiments described herein.

When temperature information is used to control coagulation, the temperature is raised at an appropriate rate, eg, at an approximate rate in the range of 25 degrees Celsius/minute to 100 degrees Celsius/minute, to a temperature endpoint in the target tissue. The approximate range of the temperature endpoint is 55 degrees Celsius to 110 degrees Celsius in one embodiment, but is not limited thereto. An appropriate rise in temperature of the surrounding tissue using the electrodes results in the release of highly conductive fluid within the cells of the target tissue. This fluid release reduces impedance around the electrode, helps prevent charring, and allows continued (or increased) energy flow to the target tissue. This release is caused by thermal damage to the cell wall. If the energy is ramped up too quickly, the fluid will be rapidly boiled or flashed off; this results in no significant benefit and helps increase the tendency of the tissue to char and lose the ability to deliver energy to the target tissue.

A third type of procedure varies the energy application to the target tissue volume based on tissue impedance information or feedback parameters combined with elapsed time. Typically this type of procedure applies power to the target tissue according to a predetermined time schedule and according to the change in impedance and the amount of electrode engagement (the engagement surface area of the electrode is a function of electrode size and electrode insertion depth) with the target tissue.

Figure 16 is a flowchart 1600 of controlling tissue coagulation according to impedance and time parameters, in one embodiment. In block 1602, after placing the electrodes in the target tissue, the user increases the power delivered to the target tissue by an amount P ₁ , where P ₁ is in the approximate range of 0.1 W/sec to 10 W/sec. In block 1604, it is determined whether the elapsed time exceeds _T1 , where _T1 is approximately in the range of 1 second to 100 seconds.

In block 1608 , when the elapsed time exceeds T ₁ , it is determined whether the impedance of the target tissue exceeds an amount I _max , where I _max approximately ranges from 1 ohm to 200 ohms. In block 1612, when the impedance exceeds I _max , then terminate the application of power to the target tissue; otherwise continue operations as described above in block 1602 .

In block 1606, when the elapsed time does not exceed _Tl measured in block 1604, it is determined whether the impedance of the target tissue is decreasing. If the impedance is not falling, continue with operation at block 1602 as described above. In block 1610, if the impedance is decreasing, power is maintained to the target tissue and operations continue to block 1608, where it is determined whether the impedance of the target tissue exceeds _Imax . In block 1612, when the impedance exceeds I _max , the application of power to the target tissue is terminated; otherwise, operations continue as described above in block 1602 .

As noted above, an example procedure for controlling tissue coagulation based on impedance parameters uses the following parameter values: P ₁ is approximately 2 W/sec; T ₁ is approximately 15 seconds; and I _max is approximately 50 ohms. These parameters are examples only, and the embodiments described herein are not limited thereto.

A fourth type of procedure varies the power application to the target tissue volume based on tissue impedance information or feedback parameters. Typically this type of procedure applies power to the target tissue based on the change in impedance and the amount of electrode engagement with the target tissue (the engagement surface area of the electrode is a function of electrode size and electrode insertion depth). As an example, in one embodiment power is applied until the impedance of the target tissue begins to drop. When the impedance starts to drop, hold the power level at a roughly constant level until the impedance stabilizes. Once the impedance stabilizes, the power level is increased to a predetermined level and maintained until the impedance begins to increase. When the impedance begins to increase, the power level can be gradually reduced in order to maintain or extend the duration of the increase in impedance.

As another example, power is applied until the impedance of the target tissue begins to drop. When the impedance starts to drop, hold the power level at a roughly constant level until the impedance stabilizes. Once the impedance stabilizes, gradually increase the power level until the impedance begins to increase. A maximum power level may be specified, but embodiments are not limited thereto. When the impedance begins to rise, the power level can be gradually reduced in order to maintain or extend the duration of the impedance rise.

Figure 17 is a flowchart 1700 for controlling tissue coagulation based on impedance parameters, in one embodiment. In block 1702, after the electrodes are placed in the target tissue, an initial impedance level I _initial is set, where I _initial is selected or determined according to the tissue type of the target tissue. In block 1704, the energy delivered to the target tissue is then increased by an amount of P ₁ , where P ₁ is in the approximate range of 0.1 W/sec to 10 W/sec. In block 1706, it is determined whether the initial impedance level I _initial has decreased by more than I _low1 , where I _low1 is approximately in the range of 0.1 ohms to 5 ohms. In block 1708, if the initial impedance level I _initial is not reduced by more than I _low1 , the power delivered to the target tissue is increased by an amount P ₂ , where P ₂ approximately ranges from 0.1 W/sec to 10 W/sec, and continues as above The operation of block 1706 is described.

In block 1710, if the initial impedance level I _initial is reduced by more than I _low1 , the power delivered to the target tissue is stabilized and maintained at the current level. In block 1712, the reduced impedance in the target tissue is set and defined as the value _Idropping . In block 1714, it is then monitored whether the drop in impedance level _Idropping exceeds the impedance level _Ilow2 , where _Ilow2 roughly ranges from 1 ohm to 20 ohms. If the drop in impedance level _Idropping has exceeded _Ilow2 , then operation continues at block 1710, where power delivery to the target tissue is maintained and operation continues as described above.

In block 1716, if the decrease in impedance level _Idropping does not exceed _Ilow2 , the power delivered to the target tissue is increased by an amount _P3 , where _P3 is approximately in the range of 0.1 W/sec to 10 W/sec. In block 1718, it is determined whether the power delivered into the target tissue is equal to or greater than _Pmax . The power level _Pmax in one embodiment is determined from a lookup table based on at least one parameter including target tissue type, initial impedance level _Iinitiial , electrode size, and electrode insertion depth, but is not limited thereto. Alternatively, _Pmax is predetermined and preset according to at least one parameter including, but not limited to, target tissue type, initial impedance level _Iinitiial , electrode size, and electrode insertion depth. In block 1716, if the current power level is below _Pmax , then the power delivered to the target tissue is increased by an amount of _P3 , and operation continues as described above.

In block 1718 , if the power level is equal to or greater than P _max , then in block 1720 the power level is maintained. Then in block 1722 , it is monitored whether the impedance level I _dropping increases beyond I _high1 . In one embodiment, the impedance level I _high1 is approximately equal to or higher than twice the impedance level I _initial , but is not limited thereto. In block 1718, if the change in impedance level _Idroppmg does not exceed _Ihigh1 , then determine whether the power level delivered to the target tissue is equal to or greater than the _Pmax amount and continue as described above. However, in block 1724, if the change in impedance level _Idropping exceeds _Ihigh1 , the application of power to the target tissue is terminated.

As noted above, one example procedure for controlling tissue coagulation based on impedance parameters employs the following parameter values: P ₁ approximately 2 W/sec; P ₂ approximately 4 W/sec; I _low1 approximately 1 ohm; and I _low2 approximately 1 ohm. Alternatively, but not limited to, power levels P ₁ , P ₂ and P ₃ may be equal. These parameters are examples only and do not limit the embodiments described herein.

18 is a plot of impedance (impedance (ohms)) 1802 and power (power (W)) 1804 (y-axis) versus time (time (minutes)) (x-axis) for controlling tissue coagulation in one embodiment. Graph. In the following description, impedance curve 1802 includes regions 1 , 2 , 3 , 5 , 6 , 9 , 10 and 12 , while power curve 1804 includes regions 4 , 7 , 8 , 11 and 13 . The graph 1800 generally represents impedance 1802 and power 1804 during a tissue coagulation procedure under impedance control employing an embodiment of a tissue coagulation system. The graph 1800 may generally be used in at least one of manual, automatic, and combined automatic/manual control of a tissue coagulation system embodiment. The graph 1800 is an example only, and does not limit the embodiments described herein.

Graph 1800 was generated using electrodes inserted into target tissue to a depth of approximately 4 to 5 centimeters, but is not limited to such. For example, an increase in electrode insertion depth will shift the impedance 1802 curve upward relative to the y-axis value and the power 1804 curve downward relative to the y-axis value. Also, different types of target tissue may shift the impedance 1802 and power 1804 curves up or down. Furthermore, electrodes of different sizes can change the shape of the impedance curve 1802, with generally larger electrodes resulting in a more gradual change in the impedance curve relative to smaller electrodes.

A procedure using the tissue coagulation system in one embodiment begins with the user placing/inserting electrodes in the target tissue. Using standard surgical techniques, the user determines the appropriate resection plane to be used. All electrodes in the device are withdrawn and the device is brought into contact with the patient so that all electrodes are properly positioned for insertion into the desired tissue. The electrodes are then inserted into the target tissue using appropriate imaging guides. Region 1 of the graph 1800 generally represents the drop in impedance due to electrode placement/insertion into the target tissue. Region 2 generally represents the impedance as it stabilizes during and after final placement of the electrode in the target tissue. Region 3 generally represents the stable impedance after the electrode is placed in the target tissue.

After the electrodes are positioned in the target tissue and the impedance stabilized, power is applied to the target tissue by inserting the electrodes as described above. Region 4 generally represents the point at which the tissue coagulation system applies power to the target tissue. Region 5 generally represents a decrease in impedance in the target tissue due to applied power. The decrease in impedance due to the application of power causes the cell membranes in the target tissue to melt or rupture and release conductive fluid to the electrode area. Region 6 generally represents the stabilized impedance in the target tissue after initial application of power to the tissue coagulation system.

Once the impedance in the target tissue stabilizes, the tissue coagulation system will increase the power applied to the target tissue. Power may be increased according to any of a variety of procedures including, for example, increasing in a stepwise manner, increasing linearly to a predetermined maximum level, increasing exponentially, and increasing until the target tissue reaches a predetermined temperature. Region 7 generally represents the increase in power applied to the target tissue and region 8 generally represents the maximum power level to which the power can be increased. Region 9 generally represents the stabilized impedance in the target tissue during/after application of increased power to the tissue coagulation system.

Due to the application of power to the target tissue, the target tissue loses water (regions 7 and 8 in the graph). Dehydration of the target tissue generally results in an increase in the impedance of the target tissue, where the rate of increase in impedance is controlled according to the applied power level. Region 10 generally represents an increase in target tissue impedance due to tissue dehydration. Region 11 generally represents the rate at which power applied to the target tissue is reduced as a function of impedance increase, while region 12 generally represents the corresponding rate of impedance increase in the target tissue.

Under automatic and/or manual control, the tissue coagulation system reduces the power applied to the target tissue at any number of rates in order to control the rate of impedance rise. For example, increasing the rate of power reduction (increasing the slope of region 11 ) can result in a slower increase in impedance (decreasing the slope of region 12 ). Likewise, reducing the rate of power reduction (decreasing the slope of region 11 ) can result in a faster increase in impedance (increasing the slope of region 12 ). The rate of power reduction is dictated by, but not limited to, the tissue type of the target tissue and/or the user.

Region 13 generally represents the termination of the application of power to the target tissue, and thus the termination of the coagulation procedure.

Turning to a fifth type of program, such programs vary the energy applied to the target tissue volume based on the temperature and impedance information or feedback parameters of the target tissue. Typically, this type of procedure applies power to the target tissue in response to changes in temperature and impedance in the target tissue. Impedance changes relate to, but are not limited to, the amount of electrode engaged with the target tissue (the engagement surface area of the electrode is a function of electrode size and electrode insertion depth).

As an example, in one embodiment, power is applied until the impedance of the target tissue begins to drop. As the impedance drops, the power level is stabilized at a roughly constant level until the impedance stabilizes. Once the impedance stabilizes, the power level is increased according to a predetermined slope. When the target tissue reaches a predetermined target temperature, the power level is varied according to the configuration of the coagulation volume to maintain the target temperature until the time the impedance increases to the predetermined target impedance. In another alternative procedure, when the target tissue reaches a predetermined target temperature, the power level is varied to maintain the target temperature until a time when the impedance increases at a predetermined rate of increase.

FIG. 19 is a graph 1900 of time versus impedance depicting an effective tissue coagulation cycle employing a tissue coagulation system, in one embodiment. During this cycle, impedance decreases as the amount of electrical contact between the electrode and tissue increases ("Electrode Placement" portion of graph 1900). Impedance then stabilizes with final placement of the electrodes relative to the tissue ("Initial Impedance" portion of graph 1900). As sufficient energy is applied to cause the release of interstitial fluid, the impedance decreases further ("Impedance Drop" portion in graph 1900), and then, as tissue temperature continues to rise, the impedance reaches a relatively steady state or constant ("Impedance Drop" in graph 1900). "Steady State Impedance" section). As tissue water loss becomes more pronounced, the relatively steady state impedance becomes slowly rising ("Impedance Rise - Tissue Water Loss" portion of graph 1900).

20 is a graph 2000 of time versus impedance depicting an undesirable tissue coagulation cycle in which the amount of power applied to the tissue is too low relative to the amount of tissue treated with the tissue coagulation system, in one embodiment. Similar to graph 1900 above, during this cycle 2000, as the amount of electrical contact between the electrode and tissue increases, impedance decreases ("Electrode Placement" portion of graph 2000); In the final placement of , the impedance stabilizes ("Initial Impedance" part of the graph 2000); with the application of sufficient energy to cause the release of interstitial fluid, the impedance further decreases ("Impedance drop" part of the graph 2000); then, with As the tissue temperature continues to rise, the impedance reaches a relatively constant value ("Steady State Impedance" portion of graph 2000). However, at the end of the cycle, the impedance did not increase with the end of the cycle ("end of cycle"). Due to insufficient power delivered, the tissue is not completely dehydrated, resulting in little or no hemostasis.

21 is a graph 2100 of time versus impedance depicting an undesirable tissue coagulation cycle in which the amount of power applied to the tissue is too high relative to the amount of tissue treated with the tissue coagulation system, in one embodiment. Similar to graph 1900 described above, during this cycle 2100, as the amount of electrical contact between the electrode and tissue increases, the impedance decreases ("electrode placement portion" in graph 2100), and then increases as the electrode moves relative to the tissue. In the final placement of , the impedance stabilizes (the "Initial Impedance" portion of the graph 2100), and with the application of sufficient energy to cause the release of interstitial fluid, the impedance further decreases (the "Impedance Drop" portion of the graph 2100), and then, with As the temperature of the tissue continues to rise, the impedance reaches a relatively constant value ("Steady State Impedance" portion of graph 2100). However, before the end of the cycle, the impedance rises rapidly ("Rapid Impedance Rise" portion of graph 2100). The rapid rise in impedance results in a relatively large tissue impedance value that terminates the cycle ("End of Cycle" portion of graph 2100). Thus, delivery of excess power to the target tissue results in incomplete coagulation of the target tissue.

Figure 22 is a flow diagram 2200 of an automated control cycle in which, in one embodiment, the amount of power delivered to tissue using the tissue coagulation system is controlled as a function of various tissue types, impedance, volume of tissue to be treated, and cycle time parameter. Parameters of delivered power include at least one of the amount of power delivered into the tissue, the rate at which power is delivered to the tissue, the duration of power delivery, and the time schedule of power delivery, but embodiments are not limited thereto.

In block 2201, the control loop 2200 begins by initializing all variables. Impedance is measured in block 2202, and the measured impedance is compared to a previous impedance value, in this case an initialization value. In block 2203, the measured impedance is compared to a predetermined minimum impedance value "IL". If the measured impedance is unstable and/or exceeds the IL value, then operation returns to block 2250, where the measurement and value check is repeated as described above with reference to blocks 2202 and 2203. As described above in Figures 1900, 2000, and 2100, this operation is typical during the "Electrode Placement" portion of the procedure. In block 2203, when the measured impedance is stable and above the IL value, operation continues in block 2204 to determine whether user input has been satisfied to begin energy application. If the user input cannot be satisfied, then operation returns to block 2250, where the measurements and value checks are repeated with reference to blocks 2202 and 2203 as described above.

When the user input is satisfied in block 2204, energy is applied to the target tissue in block 2205 at a predetermined power level, which is set or determined relative to a stable impedance value (measured in block 2203). This, in part, accounts for the amount and type of target tissue being treated. Higher impedance levels require relatively lower amounts of energy in contrast to lower impedance levels requiring relatively higher amounts of energy transfer. This portion of the flowchart corresponds to the "Initial Impedance" and "Power Application" portions of graphs 1900, 2000, and 2100 described above.

At block 2206 , along with applying energy at the preset power level, another impedance measurement is taken and compared to the first impedance value previously measured at block 2202 . When the comparison of the first and second impedance values shows no change in impedance, the applied energy or power is increased by N1% at block 2208 and operation returns to repeat the impedance measurements and comparisons at blocks 2206 and 2207 . When a comparison of the first and second impedance values shows that the impedance is increasing, in block 2209, the power is reduced and reapplied at a rate of R1 to a level L1% slightly lower than the previous level; operation then returns to repeat Impedance measurement and comparison in blocks 2206 and 2207.

When a comparison of the first and second impedance values in block 2207 shows that the impedance is neither stable nor increasing, then in block 2210 it is determined that the impedance is decreasing. At block 2211, the level of applied power is maintained at a constant level based on the impedance drop. This portion of the flowchart corresponds to the "Impedance Drop" portion of diagrams 1900, 2000, and 2100 as described above.

In block 2212, the impedance value is measured a third time, and in block 2213 it is determined whether the measured impedance value continues to decrease. In block 2213, when a comparison of previously measured impedance values indicates that the impedance is decreasing, operation returns to maintaining the applied power at a constant level and repeats the impedance measurement and comparison in blocks 2211 and 2212.

In block 2213, when a comparison of previously measured impedance values indicates that the impedance has not decreased, a fourth impedance value is measured at block 2214, and the fourth impedance measurement is compared with one or more of the previously measured impedance values in block 2215. Compared. When the comparison of the impedance measurements shows that the impedance values are not decreasing, indicating that the impedance has stabilized, then the power is increased by N2% at block 2216 and the operation returns to repeat the impedance measurements and comparisons in blocks 2214 and 2215 . This portion of the flowchart corresponds to the "steady state impedance" portion of graphs 1900, 2000, and 2100 as described above. This increase in power helps prevent the situation described with reference to diagram 2000 above from occurring without causing the end condition described in diagram 2100 above.

When the comparison of the impedance measurements (block 2215) indicates that the impedance is increasing, then at block 2217 a comparison of the percentage of cycle completion is performed. The comparison of the percentage at the end of the loop is done by comparing the elapsed time of the control loop to a predetermined amount of time, although embodiments are not so limited. At block 2218, if the cycle is more than about 100% complete, the measured impedance is compared to a predetermined high impedance value "IH". At block 2219, if the measured impedance exceeds the IH value, the loop is ended and power application to the target tissue is terminated. This portion of the flowchart corresponds to the "end of loop" portion of diagrams 1900, 2000, and 2100 as described above. If the measured impedance does not exceed the IH value (block 2218), operation returns to repeat the impedance measurements and comparisons in blocks 2214 and 2215.

However, if the comparison at block 2217 determines that the cycle is no more than about 100% complete, then the measured impedance value is evaluated and the rate of impedance increase is determined. In block 2220, the impedance increase rate is compared to a first predetermined impedance increase rate value "IR1". If the rate of impedance increase does not exceed the IR1 value (block 2220 ), then operation returns to repeat the impedance measurements and comparisons in blocks 2214 and 2215 .

If the impedance increase rate exceeds the IR1 value, then in block 2221 the impedance increase rate is also compared to a second predetermined impedance increase rate "IR2" value. If the rate of impedance increase does not exceed the IR2 value (block 2221 ), then in block 2222 the power is reduced by a relatively small amount and operation returns to repeat the impedance measurements and comparisons in blocks 2214 and 2215 .

If the impedance increases beyond the IR2 value (block 2221), the delivered power is reduced in block 2223 and reapplied at a rate R2 to a level L2% below the previous level; then operation returns to repeat the impedance measurements in blocks 2214 and 2215 And contrast.

Referring to the block numbers in flowchart 2200 as described above, example values for these variables are given below, but embodiments are not limited to the variables being these values:

frame variable Approximate range 2201 Initial Impedance Setting (IL) 5-500Ω 2202 Measure impedance 100-infinity Ω 2205 Applied power 10-150W 2205 Stable impedance value 10-250Ω 2209 Power slope (R1) L1/0.5-10 seconds 2209 Power level (L1) 50-90% of previous value 2206 Measure impedance 15-250Ω 2208 Power increase (N1) 1-25W 2207 Impedance change 1-20% 2212 Frequency of measuring impedance 0.05-5 seconds 2216 Power increase (N2) 5-20%/5-60 seconds 2217 Cycle Time 1-20 minutes 2218 Impedance (IH) 150-infinity Ω 2220 Impedance increase rate (IR1) 0.3-5W/sec 2221 Impedance increase rate (IR2) 1-20W/sec 2223 Power level % of previous value (L2) 65-95

Although the above-described control algorithm 2200 has been described as an automatic process, manual adjustments to the algorithm 2200 may also be implemented. Although manual versions of this control process may not be as precise or repeatable, they are still acceptable.

A method of applying energy to biological tissue to provide controlled hemostasis comprising at least one of: deploying an electrode array employing two or more pairs of electrodes to provide a uniform energy density in at least one target tissue volume, wherein the the electrodes comprise at least one of irregular spacing between one or more pairs of electrodes and one or more electrode diameters; positioning each electrode in the electrode array at a selected depth of the target tissue volume with the configuration, and generating a coagulated tissue surface in the target tissue volume by energy delivered to the target tissue volume from at least one energy source via electrodes, and controlling the energy based on at least one of elapsed time, temperature of the target tissue volume, and impedance of the target tissue volume transfer. The irregular spacing in one embodiment includes a first spacing between central electrodes of the electrode array that is relatively larger than a second spacing between peripheral electrodes of the electrode array.

A change in at least one property of the target tissue volume during energy delivery can be used to determine a desired level of hemostasis in one embodiment. The change includes at least one of target tissue volume impedance changes, but is not limited thereto. Changes in impedance can be determined during energy transfer.

In one embodiment, energy delivery is controlled based on at least one of a predetermined property of the target tissue volume and a relationship of the electrode array to the target tissue volume. For example, energy delivery can be controlled based on the impedance of the target tissue volume. The impedance of the target tissue volume is determined using one or more impedance measurements and controlled by comparison to at least one predetermined impedance threshold.

In one embodiment, delivering energy includes applying energy using a critically damped waveform, wherein at least one damping parameter of the waveform is determined using at least one property of the target tissue. Energy delivery using a damped waveform in one embodiment allows more energy to be delivered to the tissue than a constant application of energy. If this amount of constant energy is applied, the tissue surrounding the energy director will quickly become overheated, charred, and cause an excessive increase in impedance, stopping energy delivery prematurely. Alternatively, high levels of energy are applied depending on one or more conditions, such as an initial stable impedance. The impedance is monitored while the energy is being applied; and when the impedance starts to rise, the energy is cycled to a certain lower level for a certain period of time. Then increase the energy and repeat the cycle. This circulation allows tissue rehydration to occur during periods of lower energy application. This process is repeated until the change in impedance changes by a predetermined amount, eg, the impedance rises more rapidly. At this point the energy application and withdrawal times can be increased. This change also allows the system impedance to be more stable. As impedance changes become more pronounced, the magnitude of energy transfer decreases and may include periodic changes. As coagulation progresses, tissue impedance remains high even with a small application of energy, indicating that the coagulation process is complete.

Similarly, the initial application of energy may be too low, resulting in little or no change in system impedance. In this case, the damped wave method described herein is used to increase energy in one or more applications to help maximize the level of delivered energy. Additionally, if the initial application of energy is too great, resulting in a premature or excessive increase in impedance, in one embodiment a damped wave approach may be used to reduce the energy.

23 is a graph 2300 of applied power (percentage) versus time in damped wave energy transfer, in one embodiment. The damped wave method is described below with reference to certain points shown in the figure (eg, "1", "2", etc.), but is not limited thereto. The damped wave method proceeds as follows:

1. Start to deliver energy to the target tissue;

2. Desired slope of initial energy delivery based on preset values and/or tissue properties;

3. Initial full energy delivery of the target tissue based on preset values and/or tissue properties;

4. Initial full energy delivery duration based on changes in tissue properties;

5. Reduced energy due to tissue changes (eg, tissue properties);

6. Initial residence duration and energy slope presets and/or tissue properties;

7. A second energy delivery level based on preset values and/or tissue properties;

8. Altered residence duration and energy slope based on changes in tissue properties;

9. Altered residence duration and energy slope based on changes in tissue properties;

10. Altered residence duration and energy slope based on changes in tissue properties;

11. Altered residence duration and energy slope based on changes in tissue properties;

12. Damping energy transfer level based on changes in tissue properties;

13. The level of damping energy transfer based on tissue changes;

14. Altered dwell duration and energy slope based on tissue changes;

15. The level of damping energy transfer based on tissue changes;

16. Altered dwell duration and energy slope based on tissue changes;

17. The level of damping energy transfer based on tissue changes;

18. Continuously damped energy delivery based on tissue changes regardless of dwell duration and slope changes; and

19. Termination of delivery of energy to target tissue due to tissue changes.

FIG. 24 is a graph 2400 of applied power (percentage) versus time in damped wave energy transfer including incremental energy modulation, in one embodiment. The damped wave method is described below with reference to certain points shown in the figure (eg, "1", "2", etc.), but is not limited thereto. The damped wave method proceeds as follows:

1. Start to deliver energy to the target tissue;

2. Desired slope of initial energy delivery based on preset values and/or tissue properties;

3. Initial energy transfer to target tissue based on preset values and/or tissue properties;

4. Increased duration of energy delivery based on changes in tissue properties;

5. Reduced energy due to tissue changes (eg, tissue properties);

6. Initial residence duration and energy slope presets and/or tissue properties;

7. A second energy delivery level based on preset values and/or tissue properties;

8. Altered residence duration and energy slope based on changes in tissue properties;

9. Altered residence duration and energy slope based on changes in tissue properties;

10. Altered residence duration and energy slope based on changes in tissue properties;

11. Altered residence duration and energy slope based on changes in tissue properties;

12. Damping energy transfer level based on changes in tissue properties;

13. The level of damping energy transfer based on tissue changes;

14. Altered dwell duration and energy slope based on tissue changes;

15. The level of damping energy transfer based on tissue changes;

16. Altered dwell duration and energy slope based on tissue changes;

17. The level of damping energy transfer based on tissue changes;

18. Continuously damped energy delivery based on tissue changes regardless of dwell duration and slope changes; and

19. Termination of energy delivery due to tissue changes.

FIG. 25 is a graph 2500 of applied power (percentage) versus time in damped wave energy delivery including reduced energy modulation, in one embodiment. The damped wave method is described below with reference to certain points shown in the figure (eg, "1", "2", etc.), but is not limited thereto. The damped wave method proceeds as follows:

1. Start to deliver energy to the target tissue;

2. Desired slope of initial energy delivery based on preset values and/or tissue properties;

3. Initial full energy delivery of the target tissue based on preset values and/or tissue properties;

4. Initial full energy delivery duration based on changes in tissue properties;

5. Reduced target tissue energy due to tissue changes;

6. Initial residence duration and energy slope presets and/or tissue properties;

7. A second energy delivery level based on preset values and/or tissue properties;

8. Altered residence duration and energy slope based on changes in tissue properties;

9. Altered residence duration and energy slope based on changes in tissue properties;

10. Altered residence duration and energy slope based on changes in tissue properties;

11. Altered residence duration and energy slope based on changes in tissue properties;

12. Damping energy transfer level based on changes in tissue properties;

13. The level of damping energy transfer based on tissue changes;

14. Altered dwell duration and energy slope based on tissue changes;

15. The level of damping energy transfer based on tissue changes;

16. Altered dwell duration and energy slope based on tissue changes;

17. The level of damping energy transfer based on tissue changes;

18. Continuously damped energy delivery based on tissue changes regardless of dwell duration and slope changes; and

19. Termination of energy delivery due to tissue changes.

The above procedures and algorithms for electrode insertion depth and corresponding power settings are provided as a guideline only and can be adjusted based on user experience and thermal requirements of individual target tissue types. With respect to the InLine ^TM RF coagulation device described above, these reference insertion depths and power settings are for informational purposes only and are not a substitute for, nor should they replace, ^{the InLine TM Instructions} for Use. Before each use of the device, the user should be fully familiar with the instructions for use of InLine ^TM and follow all indications, contraindications, warnings, and precautions in the instructions for use of InLine ^TM ) and Caution.

The tissue coagulation system and related methods described above can be combined in various combinations including other components. For example, in addition to the displays and controls described above, a directional frame or frameless browser system can be used to guide and position the energy director guides/electrodes. Various guide tubes, templates, support devices, arc systems, and space digitizers are also available to aid in placement of the electrodes in the target tissue. Imaging equipment such as CT, MRI, ultrasound, etc. may also be used before, during or after placement of electrodes and/or generation of clotted tissue.

In addition to comprising many types and combinations of components, there are many alternative embodiments of the components of the tissue coagulation system described above. Some of these alternative embodiments include the energy director guide and electrode alternatives described below.

In an alternative embodiment, the energy director guide includes a soft conformal bottom element that forms a conformal projection surface between the target tissue and the energy director guide. The conformal projection elements follow the shape of the underlying target tissue surface. The conformal projection bottom element can be constructed from a wide variety of materials including silicone, biocompatible foam rubber, and polyurethane. The conformal projection bottom element can also be formed using inflated materials.

In various alternative embodiments, the energy director guides may take a variety of shapes including, but not limited to, semicircular, arcuate, and angular. Many other shapes can also be imagined by those of ordinary skill in the art.

Figure 26 shows flexible and semi-flexible guides 2602 in one embodiment. The flexible guide 2602 provides flexibility on both sides. Figure 27 shows a flexible and semi-flexible guide 2702 in another alternative embodiment, the flexible guide 2602 providing flexibility on one side. Although these guides 2602 and 2702 are configured to connect and couple power to the electrodes as described above (see Figures 2, 3, 8, 9 and 10), these guides 2602 and 2702 allow the user to vary the guides within limits. The device can be formed into the desired shape, allowing the resulting coagulation surface to match the desired outcome or avoid critical anatomical structures. Note that the desired shape, including curved portions, is formed from a series of coagulation surfaces with different sizes, but embodiments are not limited thereto.

These guides 2602 and 2702 may be flexible or semi-flexible in single or multiple planes. The single-sided flexible guides 2602 and 2702 are deformable to the shape of the target tissue under the guides. Guides 2602 and 2702 having a second side of flexibility can be used to match the shape of the surface or, if necessary, the shape of the surgical site location.

Figure 28 is an energy director array comprising, in one embodiment, an attachment component 2802 that provides for simultaneous insertion and withdrawal of energy directors 2804 into a target tissue. Attaching the energy directors to the connection member 2802 allows for simultaneous insertion or withdrawal of all energy directors 2804 through the energy director guide 102 . As one example, all energy directors 2804 may have the same length, allowing all energy directors 2804 to be inserted simultaneously to a desired depth in tissue. This is beneficial when a full thickness coagulation surface is desired, there is no anatomical contraindication to energy directors, and ease of use is important.

FIG. 29 is an energy director array including connection components 2902 connected to energy directors 2904 in another embodiment. Energy directors 2904 are selected to have non-uniform lengths because they are made to match the thickness and shape of the target tissue or organ, and/or to avoid important anatomical structures. Thus, connection component 2902 supports simultaneous insertion or withdrawal of all energy directors, regardless of length, while also enabling energy directors 2904 to avoid important anatomical structures.

In one embodiment, the energy directors may be used with a variety of housings that enclose the energy directors prior to their insertion into the target tissue. The use of a support device minimizes inadvertent insertion of the Energy Director and reduces the potential for injury to the user or patient from the Energy Director.

A number of different types of energy directors may be used in one embodiment of a tissue coagulation system. The following are descriptions of some examples of energy directors, but the embodiments are not limited thereto.

Figure 30 illustrates energy directors 3002, 3004, and 3006 that support delivery of various agents into target tissue, in one embodiment. One type of energy director 3002 supports the delivery of reagents through the inner lumen of the energy director and holes 3012 around the outer surface of the energy director 3002 .

Another type of energy director 3004 supports delivery of an agent through a lumen of the energy director and at least one aperture 3014 at the distal end of the energy director 3004 . Yet another type of energy director 3006 supports delivery of reagents through the inner lumen of the energy director as well as the porous material 3016 surrounding the outer surface of the energy director 3006 .

Energy directors 3002, 3004, and 3006 support the delivery of substances including, but not limited to, contrast agents for better visualization of detailed anatomy, sclerosing agents to help reduce general circulation in the target area, and chemotherapeutic agents for adjuvant therapy. Another example reagent is a hypertonic or hypotonic solution used to produce wet electrodes.

Figure 31 shows an energy director 2804 capacitively coupled to target tissue in one embodiment. In this embodiment the energy director 2804 is completely or nearly completely insulated. An example of such a configuration includes one or more conductive cores 2806 adapted to conduct energy, where the conductive cores 2806 are fully or nearly fully insulated with a suitable insulating material 2808, coating, or sheath. The thickness of coating 2808 varies depending on the insulating properties of the material used as an electrical insulator. Coating thicknesses for various embodiments generally range from 0.00005 inches to 0.001 inches, but are not limited thereto. In this configuration, the energy director 2804 induces energy to flow into the target tissue. As noted above, when properly applied, this energy causes heating and coagulation of the target tissue. Using capacitive coupling in this form can add relatively low resistance, resulting in relatively close spacing when using several energy directors 2804 .

In one embodiment, the tissue coagulation system includes one or more energy directors that support temperature monitoring in and/or around the target tissue. Temperature monitoring supported by energy directors supports real-time evaluation of the coagulation program both within and outside the affected tissue area. An example of this could be one or more thermocouples arranged in a configuration suitable for placement within tissue, for example on and/or within an associated energy director, where the thermocouples are coupled to Inside the temperature monitoring device.

In coagulation ablation, the tissue coagulation system and associated procedures in one embodiment deliver energy resulting in a tissue core temperature in the coldest portion of the target tissue volume in the approximate range of 65 degrees Celsius to 85 degrees Celsius. The coldest portions of the target tissue volume are typically those regions that are furthest from the energy director or are thermally shielded from the effect of the energy director by other anatomical structures.

Likewise, the tissue coagulation system and related programs deliver energy resulting in a tissue core temperature in the hottest portion of the target tissue volume in the approximate range of 85 degrees Celsius to 105 degrees Celsius. At temperatures below this, the program time may be extended unnecessarily. At temperatures above this, instability may result from surface charring due to tissue overheating. Note here: Other factors such as hypertonic agents can be used to further mitigate these conditions. Specifically, a continuous infusion of 0.9% to 8% saline solution at a rate of approximately 0.01 cc/min to 0.5 cc/min will help prevent tissue charring.

Temperature-monitored energy controllers provide the ability to control energy delivery to target tissue by employing a closed-loop or open-loop temperature feedback system to control energy. In this way, an optimal energy transfer is achieved, so that too much or too little energy is transferred. Delivering too much energy can produce superficial charred tissue, resulting in reduced or no energy delivery and incomplete coagulation. Delivering too little energy can significantly increase procedure duration, or even prevent the ability to complete the procedure. By controlling the transfer of energy to the target tissue in this way, and by using non-stick surfaces such as fluoropolymers such as polypropylene and Parylene on the energy director, charring can be minimized for optimal energy generation Transmission and tissue coagulation. In addition, as noted above, the use of temperature monitoring also provides evidence and feedback of program completion.

As noted above, in one embodiment, the energy director guide configures the energy director to provide a substantially uniform distribution of power or energy within the target tissue volume. In another embodiment, the tissue coagulation system supports the application of non-uniform energy distribution through linear or non-linear arrays. The configuration monitors a parameter such as temperature, power or impedance, and in response, controls the delivered energy to maintain the parameter within a desired target range. By using independent energy channels for each bipolar pair, the energy can be easily varied as needed. For example, for a temperature target of 80 degrees Celsius after an initial ramp at 1.5 minutes to full power or a predetermined maximum power, each zone's time-temperature slope is evaluated against a predetermined slope (approximately in the range of 50 to 80 degrees Celsius/minute). Vary power based on temperature slope to better match desired rate.

Note that patient and procedure selection is the responsibility of the medical professional-user, and that results depend on many variables, including patient anatomy, pathology, and surgical technique. The use of the tissue coagulation systems and methods described herein for thermal coagulation necrosis of soft tissue as an aid during tissue excision can result in thermal injury to the skin. In addition, thermal injury may occur to tissues or organs adjacent to the resected tissue. To minimize thermal damage to the skin or adjacent tissues, thermoregulation may be activated at the physician's discretion. These may include, but are not limited to, separation/isolation of the tissue to be treated from adjacent tissue and/or structures, in addition to application of sterile ice packs or saline-moistened gauze to cool and/or separate the tissue.

Bloodless or near bloodless resection of solid organs has been demonstrated with the ILRFA device described here during studies on the effect of blood loss during resection of liver, kidney and spleen in sheep. The study was carried out after the experimental protocol was approved by the Animal Ethics Committee of the University of New South Wales (study number A02/95).

The ILRFA device used in this study is 6 cm long and includes 6 variably inserted electrodes. The ILRFA device uses bipolar radiofrequency energy to create a coagulated tissue surface for bloodless resection of solid organs. Power for the ILRFA device was generated using a 1500 RITA generator (Rita Medical Systems, Sunnyvale, California) with a maximum power of 150 watts. Connect the generator to a laptop computer to graphically display and record data. The amount of power applied was based on the resection depth studied for the liver.

In this study, all sheep were induced with Zoletil 100 (Virbac NSW, Australia). Sheep were intubated and general anesthesia was maintained with halothane (1-2%). The sheep's pulse and oxygen saturation were continuously monitored, and blood oxygen was recorded every 15 minutes. This is done to ensure that normal vital signs are maintained, which could otherwise affect the volume and rate of bleeding.

After application of ILRFA to spleen, kidney and liver of sheep, organectomy was performed by diathermy. This region was then matched to the corresponding resection of the same organ that did not benefit from the ILRFA device. Measure the amount of bleeding by weighing the swab.

These studies included a total of 8 spleen, 5 liver and 5 nephrectomy in sheep and compared resection using ILRFA and thermodialysis with thermodialysis alone. The results of liver resection were as follows: the average blood loss with ILRFA was 43.2±36 milliliters (ml); the average blood loss without ILRFA was 221.8±147 ml; P value 0.005. The results of nephrectomy were as follows: the average blood loss with ILRFA was 86.4±106ml; the average blood loss without ILRFA was 388.2±152ml; P value 0.02. The results of splenectomy were as follows: the average blood loss with ILRFA was 33.1±17ml; the average blood loss without ILRFA was 123.4±72ml, P value 0.005.

Following the above study on the effect of blood loss during liver, kidney and splenectomy in sheep, studies in humans were carried out. Eight patients were used in the study and all procedures were performed under general anesthesia after liver mobilization and intraoperative ultrasound. No attempt was made to generate a lower central venous pressure ("CVP"), and no Pringle inflow occlusion maneuver was performed. During surgery, mark the resection plane with thermodiathermy. A limb of the resection plane was then excised with ILRFA and resected with an ultrasonic aspirator (Selector, Integra Neurosciences, UK). Ultrasonic aspirator was used to resect the remaining part of the liver resection surface, which was used as a control for ILRFA.

The ILRFA device used in the study was a 5 cm long device that included 6 electrodes, each 10 cm long, distributed along the device. Each electrode can be inserted to a variable depth into the liver parenchyma. Connect the ILRFA unit to the RITA 1500 generator. Power was applied to the ILRFA device according to the depth of electrode insertion as follows: 25 W when the electrode was inserted to a depth of 1 cm; 35 W when the electrode was inserted to a depth of 2 cm; 45 W when the electrode was inserted to a depth of 3 cm; 55 watts were applied at a depth of 4 cm; 60 watts were applied when the electrode was inserted to a depth of 5 cm.

All operations were carried out as planned without morbidity or death. Recovery is 9 to 12 days after surgery. The average hemorrhage volume per square centimeter with ILRFA was 6.5±3.7ml, while the average hemorrhage volume per square centimeter with ultrasonic aspirator alone was 20.4±8.7ml. ILRFA therefore significantly reduced bleeding per square centimeter (p=0.004). Argon beam coagulation was required for all non-ILRFA resected surfaces, whereas argon beam coagulation was not required for surfaces treated with the ILRFA device.

The tissue coagulation system described above includes: an energy source, two or more pairs of bipolar energy directors configured for insertion into a volume of biological tissue, and the energy directors configured to An energy director guide for producing at least one coagulated tissue plane in a volume, wherein the energy director configuration results in a substantially uniform energy distribution in the tissue volume; wherein the guide comprises a series of channels receiving the energy director in an alternating polarity series, wherein varying the channel spacing according to the number of pairs of energy directors accepted at the energy director guides such that the relative spacing of the centermost channels is maximized and the relative spacing of the endmost channels is minimized; and wherein the guides independently couple the energy source to each energy controller.

In one embodiment, the tissue coagulation system comprises an energy source comprising a radio frequency generator.

In one embodiment, the energy director guide further ensures a selected depth location of the energy director within the tissue volume.

In one embodiment, the two or more pairs of bipolar energy directors include 3 pairs of bipolar energy directors. Alternatively, in one embodiment said two or more pairs of bipolar energy directors comprise 4 pairs of bipolar energy directors.

In one embodiment, the energy director further comprises at least one component selected from the group consisting of a temperature sensor, a thermocouple, an infusion set, and an optical tissue monitor.

In one embodiment, the tissue coagulation system further comprises at least one controller coupled between the energy source and the bipolar energy directors, wherein the controller supports automatic control of energy delivery to each bipolar energy director .

In one embodiment, the energy directors are inserted into the volume of biological tissue at independently varying depths.

In one embodiment, the energy director is internally cooled.

In one embodiment, the tissue coagulation system further comprises at least one support device, wherein the support device includes an energy director and is configured to be coupled to an energy director guide, wherein the energy director extends from the support device, and Inserted into a biological tissue volume.

In one embodiment, uniform energy distribution includes uniform current density.

In one embodiment, the series of alternating polarity includes at least one electrode of positive polarity in series with at least one electrode of negative polarity.

The above system for producing at least one plane of coagulated tissue in a volume of biological tissue comprising at least one guide means comprising a series of channels arranged in alternating polarity series of two or more sets of bipolar electrodes, wherein the channels are spaced apart varies according to the total number of bipolar electrodes received in the guide, such that the relative spacing of the most central channels is maximized and the relative spacing of the extreme channels is minimized, wherein the guide ensures a selected position of each electrode in the target biological tissue, And each bipolar electrode is coupled to at least one energy source.

A method of using the tissue coagulation system described above for producing at least one coagulated tissue plane in biological tissue comprises: positioning an electrode guide on the surface of a target tissue region comprising a target tissue volume, wherein the electrode guide comprises a series of channels arranged in alternating Polar series configurations of two or more pairs of bipolar electrodes, where the channel spacing varies according to the total number of bipolar electrodes to be accepted in the guide, such that the relative spacing of the most central channels is greatest and the relative spacing of the extreme channels is smallest; Using the electrode guide to ensure a selected depth of the bipolar electrode in the target tissue volume; using the electrode guide to couple at least one energy source to the bipolar electrode and provide a substantially uniform energy density distribution in the target tissue volume; and At least one coagulated tissue surface is generated in the tissue. In one embodiment the method for use with a tissue coagulation system further comprises infusing a solution into the target tissue volume via at least one of the bipolar electrodes, wherein the solution is a hypertonic solution, a hypotonic solution, a contrast agent, a sclerosing agent, and chemotherapy at least one of the agents.

A method for producing at least one coagulated tissue plane in a target tissue for use with the tissue coagulation system described above comprises: positioning an electrode guide adjacent to a target tissue volume; placing two or more pairs of bipolar electrodes through the electrode guide inserting into the target tissue volume in a series of alternating polarities; employing an assembly of electrode guides to ensure a selected depth of the bipolar electrode in the target tissue volume; coupling at least one energy source to the target tissue volume via the bipolar electrode; controlling delivering energy to achieve a substantially uniform distribution of energy within the target tissue volume, wherein a target temperature in the target tissue volume is above a temperature approximately in the range of 55 degrees Celsius to 60 degrees Celsius; and creating a coagulated tissue surface within the target tissue volume. The method further includes measuring the target temperature at the one or more electrodes. The method further includes measuring the target temperature at one or more points in the target tissue volume.

The above tissue coagulation device for tissue resection procedures in mammals comprises: a support having first and second end portions and a surface extending between the first and second end portions; and a plurality of at least first, second and third elongated radio frequency electrodes, wherein said electrodes extend from the surface at spaced locations between first and second end portions, the first and second electrodes being spaced apart by a first distance, The second and third electrodes are separated by a second distance different from the first distance, the first and second distances being selected such that when the first, second and third electrodes are placed in tissue, the first and second The energy distribution between the electrodes and between the second and third electrodes is substantially uniform.

In one embodiment, the first, second and third electrodes are parallel.

In one embodiment, the first, second and third electrodes are needle electrodes.

The above tissue coagulation device for tissue resection procedures in a mammalian body further comprises a fourth elongated radio frequency electrode spaced apart from the third electrode by a third distance different from the first and second distances, an appropriate third distance being selected, Such that when the second, third and fourth electrodes are positioned in the tissue, the energy distribution between the second and third electrodes and the energy distribution between the third and fourth electrodes are substantially uniform.

The above tissue coagulation device for tissue excision procedures in mammals further comprises a radio frequency generator coupled to the first and second electrodes for providing the first voltage to the first electrode and the second voltage to the second electrode.

The above tissue coagulation device for tissue excision procedures in mammals further includes a radio frequency generator coupled to the radio frequency electrodes for providing a first voltage to the first and second electrodes and a second voltage to the third and fourth electrodes.

Method for resection of a portion of a target organ in a mammal for use with the tissue coagulation system described above, wherein a support is employed having first and second end portions and a surface extending between the first and second end portions and a plurality of electrodes extending from the surface and sequentially spaced between the first and second end portions, the method comprising: positioning the electrodes adjacent to the target organ; extending the electrodes into the target organ; providing a first voltage of radiofrequency energy to the electrodes, and supplying a second voltage of radiofrequency energy to a second plurality of electrodes such that the radiofrequency energy propagates between the first and second sets of electrodes to form a wall of resected tissue in the target organ; and cutting into the target organ near the resected tissue wall to resect part of the target organ.

The method for resecting a portion of the target organ further includes estimating a transverse dimension of the target organ and sizing the electrode as a function of the transverse dimension to prevent the electrode from extending beyond the target organ when the surface is substantially flush with the target organ.

The method for resecting a portion of the target organ further includes separating the target organ from an adjacent organ to prevent the electrode from penetrating the adjacent organ when the electrode is extended into the target organ. In one embodiment the separation is by placing a barrier between the target organ and the adjacent organ to protect the adjacent organ from the electrodes.

The coagulation system for biological tissue described above comprises a handle, a radio frequency (RF) generator, and an electrode array comprising two or more pairs of bipolar electrodes slidably coupled in channels of the handle, wherein the electrodes are electrically coupled to The RF generator, electrode array is configured to deliver an equilibrium energy density into a target volume of biological tissue, wherein the equilibrium energy density causes thermal coagulation necrosis of a rectangular volume of biological tissue.

In one embodiment the rectangular tissue volume has an approximate width in the range of 0.5 cm to 1 cm.

In one embodiment each electrode of the electrode array is inserted at an independently variable depth into the target volume of biological tissue, and the handle secures the selected depth position.

In one embodiment the two or more pairs of bipolar electrodes comprise at least one of three pairs of bipolar electrodes and four pairs of bipolar electrodes.

In one embodiment the system further comprises at least one temperature sensor. In one embodiment the temperature sensor is an assembly of one or more bipolar electrodes, but is not limited thereto.

In one embodiment the system further comprises at least one thermocouple.

In one embodiment the system further comprises a controller coupled between the RF generator and the bipolar electrodes to provide automatic control of the delivery of energy to each bipolar electrode.

In one embodiment the one or more bipolar electrodes include at least one internal channel configured to carry a fluid.

In one embodiment the bipolar electrodes of the electrode array are arranged in an alternating polarity series comprising at least one electrode of positive polarity in series with at least one electrode of negative polarity.

Configuring an embodiment of the electrode array to deliver a balanced energy density includes: according to at least one of the total number of bipolar electrodes in the electrode array, the diameter of each bipolar electrode, and the selected insertion depth of each bipolar electrode to position the electrodes in the array.

In one embodiment the coagulation system comprises a radio frequency (RP) generator and an electrode array, wherein the electrode array comprises two or more pairs of bipolar electrodes slidably coupled in channels of the handle, and the electrodes are electrically coupled to an RF generator. device. The electrode array is configured to deliver an equilibrium energy density into a target volume of biological tissue using at least one irregular spacing between channels having one or more different diameters and electrodes, wherein the equilibrium energy density results in a rectangular shape of the biological tissue Volumetric thermal coagulation necrosis.

In one embodiment the spacing between bipolar electrodes decreases towards one or more ends of the electrode array.

In one embodiment the spacing between the bipolar electrodes varies according to at least one of the total number of bipolar electrodes in the electrode array, the diameter of the electrodes, and the selected insertion depth of each electrode.

In one embodiment, balanced energy density includes uniform energy distribution and uniform current density.

In one embodiment the system further comprises at least one sensor.

In one embodiment the rectangular volume of tissue has an approximate width in the range of 0.5 cm to 1 cm.

In one embodiment the tissue coagulation system comprises a radio frequency (RP) generator and an electrode array, wherein the electrode array comprises two or more pairs of bipolar electrodes slidably coupled in channels of the handle, wherein the electrodes are electrically coupled to the RF generator. The electrode array and RF generator are configured to deliver a uniform energy density in a target volume of biological tissue by delivering energy to the target tissue based on at least one of the time taken for delivery, the temperature of the target tissue volume, and the impedance of the target tissue volume One to control delivery, in which equilibrium energy density results in thermal coagulation and necrosis of a rectangular volume of biological tissue. In one embodiment the rectangular volume of tissue has a width approximately in the range of 0.5 cm to 1 cm.

The temperature of the target tissue volume includes at least one of: a temperature of at least one region of the target tissue volume, a temperature change of at least one region of the target tissue volume, and a rate of temperature change of at least one region of the target tissue volume.

In one embodiment the system further comprises at least one sensor for sensing at least one of temperature and impedance in the target tissue volume.

In the system of an embodiment, controlling delivery based on at least one of time taken for delivery, temperature of the target tissue volume, and impedance of the target tissue volume further comprises: increasing the rate of energy delivery to the target tissue volume by a first amount; when Increase the energy transfer rate when the temperature increase rate in the target tissue volume is equal to or less than the minimum rate; decrease the energy transfer rate when the temperature increase rate in the target tissue volume is equal to or greater than the maximum rate; decrease when the temperature in the target tissue volume is greater than the maximum temperature an energy delivery rate; increasing the energy delivery rate to the target tissue volume by a second amount when the temperature of the target tissue volume is below the maximum temperature; and terminating energy delivery to the target tissue volume when the elapsed time for delivery exceeds the maximum time.

In the system of an embodiment, controlling delivery based on at least one of time taken for delivery, temperature of the target tissue volume, and impedance of the target tissue volume further comprises: increasing the rate of energy delivery to the target tissue volume by a first amount; when maintaining a constant rate of energy delivery while the impedance of the target tissue decreases; and, terminating energy delivery to the target tissue volume when the impedance of the target tissue exceeds a maximum impedance. The rate of energy delivery to the target tissue volume is further increased by the first amount as the impedance of the target tissue increases or remains approximately constant.

In the system of one embodiment, controlling the delivery based on at least one of the time taken for delivery, the temperature of the target tissue volume, and the impedance of the target tissue volume further comprises: determining a first impedance of the target tissue volume; delivering energy to the tissue volume; monitoring a first impedance and delivering energy at a second rate when the decrease in the first impedance is below a first threshold; determining a second impedance of the target tissue volume in response to the decrease in the first impedance exceeding the first threshold; monitoring the second impedance and delivering energy at a third rate when the second impedance decreases below a second threshold; and, terminating energy delivery to the target tissue volume when the impedance of the target tissue exceeds the maximum impedance.

In the system of one embodiment, controlling the delivery based on at least one of the time taken for delivery, the temperature of the target tissue volume, and the impedance of the target tissue volume further comprises: determining the impedance of the target tissue volume; Delivering energy until the impedance stabilizes at a lower impedance; then delivering balanced energy to the target tissue volume at a second rate until the impedance exceeds a threshold impedance.

In one embodiment, the tissue coagulation system includes a method of applying energy to biological tissue to provide controlled hemostasis. The method includes configuring an electrode array to provide a uniform energy density into at least one target tissue volume using two or more pairs of electrodes including irregular spacing between the one or more pairs of electrodes. The method also includes positioning each electrode of the electrode array at a selected depth in the target tissue volume using the configuration. The method also includes generating a coagulated tissue surface in the target tissue volume by energy delivered into the target tissue volume from at least one energy source via electrodes, and based on at least one of the elapsed time, the temperature of the target tissue volume, and the impedance of the target tissue volume. One to control energy transfer.

In one embodiment, the irregular spacing includes a first spacing between central electrodes of the electrode array that is relatively larger than a second spacing between peripheral electrodes of the electrode array.

In one embodiment the delivered energy is controlled based on at least one of a predetermined property of the target tissue volume and the relationship of the electrode array to the target tissue volume.

In one embodiment the delivered energy is controlled based on the impedance of the target tissue volume, wherein the impedance of the target tissue volume is determined using multiple impedance measurements and the impedance is controlled by comparison to at least one predetermined impedance threshold.

In one embodiment the delivered energy is a critically damped waveform, wherein at least one property of the target tissue volume is used to determine at least one damping parameter of the waveform.

In one embodiment, the method includes using a change in at least one property of the target tissue volume during energy delivery to determine the desired level. In one embodiment the change comprises at least one of changes in target tissue volume impedance. In one embodiment the change in impedance is determined during one or more of the at least one dwell period and during energy delivery.

In one embodiment the energy transferred comprises electrical energy. The electrical energy in one embodiment includes at least one of high frequency electrical energy, radio frequency (RF) energy, and microwave energy.

In one embodiment, controlling energy delivery based on temperature includes one or more of: increasing the energy delivered to the target tissue by a first amount, determining the rate of temperature change in the target tissue, and determining when the rate of temperature change is less than or equal to the first amount At least one of the rates further increases the delivered energy beyond the first amount.

In one embodiment controlling energy transfer based on temperature includes reducing the transferred energy when the rate of temperature change is determined to be at least one of greater than and equal to the second rate. In one embodiment the method further comprises one or more of: determining that the rate of temperature change in the target tissue is within the range defined by the first rate and the second rate, determining the temperature of the target tissue, and when the temperature is determined to be Reduces delivered energy above maximum temperature. In one embodiment when the temperature is determined to be below the maximum temperature, the energy delivered into the target tissue is increased. When the time taken for energy delivery to the target tissue is higher than the maximum time, the energy delivery to the target tissue is terminated.

Controlling energy delivery based on impedance includes one or more of: increasing energy delivered to the target tissue by a first amount, determining a time taken to deliver energy to the target tissue, and determining an impedance of the target tissue. In one embodiment energy delivery to the target tissue is terminated when the elapsed time is above the maximum time and the impedance is above the maximum impedance. In one embodiment, the energy delivered is increased beyond a first amount when the elapsed time is approximately equal to or below the maximum time and the impedance is approximately constant or increasing. In one embodiment, the delivered energy is maintained at the first amount when the elapsed time is approximately at or below the maximum time and the impedance decreases. In one embodiment, energy delivery to the target tissue is terminated when the impedance is above the maximum impedance.

Controlling energy delivery based on impedance includes one or more of: setting an initial impedance level based on the target tissue type, increasing energy delivered to the target tissue by a first amount, and determining an impedance of the target tissue. In one embodiment the delivered energy is increased to a second amount greater than the first amount when the impedance is reduced to a first reduced impedance equal to or higher than the first threshold impedance. In one embodiment, the delivered energy is maintained at the first amount when the impedance decreases to a first reduced impedance that is less than a first threshold impedance.

In one embodiment, the method includes setting the first reduced impedance to a second threshold impedance.

In one embodiment, the method maintains the delivered energy at a second amount when the impedance decreases to a second reduced impedance that is less than a second threshold impedance.

In one embodiment, the method increases the delivered energy by a third amount greater than the second amount when the second reduced impedance is equal to or greater than the second threshold impedance.

In one embodiment, the method determines the total amount of energy delivered to the target tissue since the initial application of delivered energy.

In one embodiment, the method increases the energy delivered when the total amount of energy delivered is less than the maximum energy.

In one embodiment, the method maintains the delivered energy at a third amount when the total amount of delivered energy is at or above the maximum energy. In one embodiment the method determines the impedance of the target tissue. In one embodiment, the method determines the total amount of energy delivered to the target tissue since initial application of the delivered energy when the impedance is less than or equal to a third threshold impedance. The method terminates delivery of energy to the target tissue when the impedance is above a third threshold impedance.

In one embodiment, a tissue coagulation system includes a system for controlled hemostasis in biological tissue. A system in one embodiment includes at least one generator. The system includes an electrode array slidingly coupled into the channel of the handle and electrically coupled to the generator, the electrode array comprising two or more pairs of bipolar electrodes comprising irregularly spaced, the electrode array and generator configured to deliver a uniform energy density in a target volume of biological tissue by delivering energy to the target tissue, and the delivery is controlled according to at least one of the following parameters: time taken for delivery, target tissue volume temperature and impedance of the target tissue volume.

Irregular spacing in one embodiment includes a first spacing between central electrodes of the electrode array that is relatively larger than a second spacing between peripheral electrodes of the electrode array.

In one embodiment, the delivered energy is controlled based on the impedance of the target tissue volume, wherein the impedance of the target tissue volume is determined using multiple impedance measurements and controlled by comparison to at least one predetermined impedance threshold.

In one embodiment the delivered energy is a critically damped waveform, wherein at least one property of the target tissue volume is used to determine at least one damping parameter of the waveform.

In one embodiment the system comprises at least one electrode configured as at least one sensor, wherein a change in at least one property of the target tissue volume is used during energy delivery to determine the desired level is determined from information from the at least one sensor of hemostasis.

In one embodiment, the system includes a controller that controls the delivered energy based on at least one of a predetermined property of the target tissue volume and a relationship of the electrode array to the target tissue volume.

In one embodiment, the controlling includes controlling energy delivery as a function of temperature, comprising one or more of: increasing the energy delivered to the target tissue by a first amount, determining a rate of temperature change in the target tissue, and when the temperature Further increasing the delivered energy beyond the first amount when the rate of change is determined to be at least one of less than and equal to the first rate.

In one embodiment, the system reduces the delivered energy when the rate of temperature change is determined to be at least one of greater than and equal to the second rate.

In one embodiment, the system determines that the rate of temperature change in the target tissue is within a range defined by the first rate and the second rate, determines the temperature of the target tissue, reduces the delivered energy when the temperature is determined to be above a maximum temperature, Energy delivery to the target tissue is increased when the temperature is determined to be below the maximum temperature, and/or energy delivery to the target tissue is terminated when the time taken to deliver energy to the target tissue is above the maximum time.

In one embodiment, the controlling comprises controlling energy delivery based on impedance comprising one or more of: increasing the energy delivered to the target tissue by a first amount, determining the time taken to deliver energy to the target tissue, and determining The impedance of the target tissue.

In one embodiment, the system further comprises one or more of: terminating energy delivery to the target tissue when the elapsed time is above the maximum time and the impedance is above the maximum impedance, and when the elapsed time is approximately equal to or below the maximum time and The impedance is substantially constant or increases further increasing the delivered energy beyond the first amount.

In one embodiment, the system further comprises one or more of: maintaining the delivered energy at the first amount when the elapsed time is approximately equal to or below the maximum time and the impedance decreases, and terminating when the impedance is above the maximum impedance Deliver energy to target tissue.

In one embodiment said controlling further comprises controlling energy delivery based on impedance comprising one or more of: setting an initial impedance level based on the target tissue type, increasing the energy delivered to the target tissue by a first amount, and Determine the impedance of the target tissue.

In one embodiment the system further comprises one or more of: increasing the delivered energy to a second amount higher than a first amount when the impedance is lowered to a first reduced impedance equal to or higher than a first threshold impedance amount, and maintaining the delivered energy at the first amount when the impedance decreases to a first reduced impedance below a first threshold impedance.

In one embodiment the system further comprises one or more of: setting the first reduced impedance to a second threshold impedance, maintaining the delivered impedance when the impedance drops to a second reduced impedance below the second threshold impedance The energy is at a second amount, and the delivered energy is increased to a third amount above the second amount when the second reduced impedance is at or above the second threshold impedance.

In one embodiment the system further comprises one or more of: determining the total energy delivered to the target tissue since initial application of the delivered energy, increasing the delivered energy when the total delivered energy is below the maximum energy, and The delivered energy is maintained at the third amount when the total delivered energy is equal to or greater than the maximum energy.

In one embodiment the system further comprises one or more of: determining the impedance of the target tissue, determining the total energy delivered to the target tissue since the initial application of the delivered energy when the impedance is less than or equal to a third threshold impedance, and terminating delivery of energy to the target tissue when the impedance is above a third threshold impedance.

Unless the context clearly requires otherwise, in the specification and claims, the words "comprise", "comprising", etc. shall be construed as inclusive and not exclusive or exhaustive; i.e., its meaning is "including, but not limited to" . Words employing the singular or the plural also include the plural or singular respectively. Furthermore, the words "herein," "hereinafter," and words of similar import, when used in this application, should be read with reference to this application as a whole and not to any specific portions of this application. When the word "or" is used in a list of two or more items, the word overrides all of the following interpretations of that word: any item in the list, all items in the list, and any combination of items in the list .

The above description of exemplary embodiments of the tissue coagulation system should not be construed as exhaustive, nor as limiting the tissue coagulation system to the precise form disclosed. While specific embodiments of tissue coagulation systems and examples thereof are disclosed herein for illustrative purposes, various equivalent modifications can be made within the scope of tissue coagulation systems, as will be known to those of ordinary skill in the art. The teachings of the tissue coagulation systems provided herein can be applied to other coagulation systems, resection systems, and medical devices, not just the tissue coagulation systems described above.

The elements and acts of the various embodiments described above can be combined to provide further embodiments. These and other changes to the tissue coagulation system can be made in light of the above detailed description. Aspects of the tissue coagulation system can be adjusted, if necessary, to provide further embodiments of the tissue coagulation system utilizing the systems, functions and concepts of the various patents and applications described above.

In conclusion, in the following claims, the terms used should not be construed to limit the tissue coagulation system to the specific embodiments disclosed in the specification and claims, but should be construed to include all medical systems operating under the claims. Accordingly, the tissue coagulation system is not limited by the disclosure, but rather the scope of the tissue coagulation system is determined entirely by the claims.

Although certain aspects of the tissue coagulation system are provided below in certain claim forms, the inventors intend to include various aspects of the tissue coagulation system in any number of claim forms. Accordingly, the inventors reserve the right to add additional claims after filing the application to implement such additional claim forms for other aspects of the tissue coagulation system.

Claims (14)

1. carry out controlled hemostatic system in biological tissue, it comprises:

Generator,

Slip is coupled in the handle passage and is electrically coupled to the electrod-array of generator, this electrod-array comprises two pairs or many to bipolar electrode, described bipolar electrode comprises the irregular spacing between one or more pairs of electrodes, electrod-array and generator are configured to transmit uniform energy density in the target volume of biological tissue, its by transmit to target tissue energy and according at least a control transmission in the impedance of the temperature of transmitting used time, target volume and target volume realize and

Controller, it is according at least a institute's energy delivered of controlling in the relation of the predetermined character of target volume and electrod-array and target volume, wherein according to the impedance Control energy delivery, it comprises: will increase by first amount to the target tissue energy delivered, determine to transmit the used time of energy and the impedance of definite target tissue to target tissue; Wherein when the used time is higher than maximum time and impedance and is higher than maximum impedance, termination is transmitted energy to target tissue, with be substantially equal to when the used time or be lower than maximum time and impedance constant or when increasing, will further increase by first amount that surpasses to the target tissue energy delivered.

2. according to the system of claim 1, wherein irregular spacing comprises first between the electrod-array central electrode at interval, and the described first interval ratio electrode array periphery interelectrode second is bigger relatively at interval.

3. according to the system of claim 1, wherein control institute's energy delivered, wherein adopt repeatedly impedance measurement to determine the impedance of target volume according to the impedance of target volume, and by with relatively the controlling of at least one predetermined impedance threshold.

4. according to the system of claim 1, wherein institute's energy delivered is the waveform of critical damping, wherein adopts at least a character of target volume to determine at least a damping parameter of waveform.

5. according to the system of claim 1, further comprise at least one electrode that is configured at least one pick off, wherein during energy delivery, adopt the variation of at least a character of target volume to determine the hemostatic aspiration level according to determining from the information of at least one pick off.

6. according to the system of claim 1, wherein also transmit according to the temperature control energy, it comprises:

To increase by first amount to the target tissue energy delivered;

Determine the rate temperature change in the target tissue; With

When rate temperature change is confirmed as being less than or equal to first rate, institute's energy delivered is further increased above first amount.

7. according to the system of claim 6, further comprise when rate temperature change is confirmed as being greater than or equal to second speed, reduce institute's energy delivered.

8. according to the system of claim 7, further comprise:

Determine that rate temperature change is in by the first rate and the second speed restricted portion in the target tissue;

Determine the temperature of target tissue;

When temperature is confirmed as being higher than maximum temperature, reduce institute's energy delivered;

When temperature is confirmed as being lower than maximum temperature, increase to the target tissue energy delivered; With

When the target tissue transmission used time of energy is higher than maximum time, stop transmitting energy to target tissue.

9. according to the system of claim 1, further comprise:

When the used time is substantially equal to or be lower than maximum time and impedance reduction, will maintain first amount to the target tissue energy delivered;

When impedance is higher than maximum impedance, stop transmitting energy to target tissue.

10. according to the system of claim 1, wherein, comprising according to the impedance Control energy delivery:

Type according to target tissue is set the initial impedance level;

To increase by first amount to the target tissue energy delivered; With

Determine the impedance of target tissue.

11. the system according to claim 10 further comprises:

When impedance drop is low to moderate the first reduction impedance that is equal to or higher than the first threshold impedance, institute's energy delivered is further increased to second amount of first amount that is higher than;

When impedance drop is low to moderate the first reduction impedance that is lower than the first threshold impedance, institute's energy delivered is maintained first amount.

12. the system according to claim 11 further comprises:

Reducing impedance setting with first is second threshold impedance;

When impedance drop is low to moderate the second reduction impedance that is lower than second threshold impedance, institute's energy delivered is maintained second amount;

When the second reduction impedance is equal to or higher than second threshold impedance, institute's energy delivered is increased to the 3rd amount.

13. the system according to claim 12 further comprises:

Definite gross energy that has transmitted to target tissue since the energy that transmits from initially applying;

When the gross energy that is transmitted is lower than ceiling capacity, increase institute's energy delivered;

When institute's energy delivered total amount is equal to or higher than ceiling capacity, institute's energy delivered is maintained the 3rd amount.

14. the system according to claim 13 further comprises:

Determine the impedance of target tissue;

When the 3rd threshold impedance is less than or equal in impedance, determine the gross energy that has transmitted to target tissue since the energy that transmits from initially applying;

When impedance is higher than the 3rd threshold impedance, stop transmitting energy to target tissue.

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