WO2024236502A1

WO2024236502A1 - Cryoablation system, method and apparatus

Info

Publication number: WO2024236502A1
Application number: PCT/IB2024/054728
Authority: WO
Inventors: Kieran P. Murphy
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-05-15
Filing date: 2024-05-15
Publication date: 2024-11-21
Anticipated expiration: 2025-11-15

Abstract

The present specification provides a novel cryoablation system, apparatus and method that includes a needle with at least one working fluid cavity and a wicking structure. The needle can be parallel to the working fluid cavity. The needle can be hollow. The working fluid cavity is connected to a controller for cycling hot and cold working fluid into the cavity so that the distal tip of the needle can be used at a target site in a patient to provide cryoablation therapy.

Description

CRYOABLATION SYSTEM, METHOD AND APPARATUS

CROSS RELATED APPLICATIONS

[0001] The present disclosure claims priority to US provisional patent application 63/502398 filed May 15, 2023, US provisional patent application 63/472710 filed June 13, 2023 and US provisional patent application 63/521431 filed June 16, 2023, the contents of which are incorporated herein by reference.

FIELD

[0002] The present disclosure generally relates to cryoablation and more particularly relates to a cryoablation system, method and needle.

BACKGROUND

[0003] Cryoablation is an evolving percutaneous technique that can be used for a variety of interventions including pain therapy and tumour ablation. Prior art cryoablation medical equipment tends to be bulky and awkward, leading to decreased availability of cryoablation therapy. Prior art cryoablation equipment also tends to rely on liquid nitrogen, helium or liquid argon, which further increases the complexity and size of cryoablation medical equipment. Prior art cryoablation equipment includes attempts to reduce the size of the equipment, such as US7238184B2, (incorporated herein by reference) however, the probe is quite intricate and complex.

[0004] Cryoablation is also known as cryoneuroablation or cryoneurolysis. It is a medical procedure that uses cold temperatures to disrupt nerve function temporarily or permanently. This procedure is used to relieve chronic pain or to treat certain conditions, such as malignant tumors, by inducing localized cell death (necrosis). The prior art process involves the use of a cryoprobe, which is a small, needle-like device that can be inserted through the skin and directed to the targeted nerve, for example, under the guidance of imaging techniques such as ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI).

[0005] Once the cryoprobe is in place, the probe tip is cooled, creating a cold zone around the probe tip. This extreme cold causes the water in the nearby cells to freeze, leading to cell rupture and death. In the case of nerve cells, the cold temperatures interrupt the conduction of nerve signals, thereby numbing the area and providing pain relief.

[0006] The effects of cryoablation can be temporary or permanent, depending on the specific technique used and the duration of the treatment. When used for pain relief, the effects can last for several weeks to months as the nerve regenerates. In some cases, cryoablation is used as a permanent solution, such as when it's used to destroy cancerous tissues. Some cryoprobes rely on a source of a cryogenic substance, typically liquid nitrogen or argon gas, which can rapidly cool the probe tip to extremely low temperatures.

[0007] A dermatology probe that incorporates both a heat pipe and a thermoelectric device is disclosed in Hamilton A, Hu J. “An electronic cryoprobe for cryosurgery using heat pipes and thermoelectric coolers: a preliminary report”. J Med Eng Technol. 1993 May-Jun; 17(3): 104-9. Docket No. 56812-3036: 10.3109/03091909309016215. PMID: 8263903., the contents of which are incorporated herein by reference.

[0008] Accordingly, there is growing interest in cryoablation and its effective application.

BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 shows a system for cryoablation.

[0010] Figure 2 shows a block diagram of the controller of the system of Figure 1.

[0011] Figure 3 shows a side cross section of the distal tip of the needle of Figure [0012] Figure 4 shows an end cross section of the distal tip through the lines 4-4 of Figure 3.

[0013] Figure 5 shows an end cross section of the distal tip through the lines 5-5 of Figure 3.

[0014] Figure 6 shows a partial perspective view of the distal tip of Figure 3.

[0015] Figure 7 shows variant on the system of Figure 1.

[0016] Figure 8 shows a variant on the needle of Figure 3.

[0017] Figure 9 depicts the placement of the needle of Figure 8 during insertion into a target site.

[0018] Figure 10 shows a side sectional schematic view of a prior art needle which operates based on the Joule-Thomson effect.

[0019] Figure 11 shows a schematic representation of a variant of the needle of Figure 8.

[0020] Figure 12 shows a cross-section of the needle of Figure 11.

[0021] Figure 13 presents a graph depicting the test results obtained using the needle of Figure 11.

[0022] Figure 14, Figure 15, Figure 16 and Figure 17 help further elaborate on Peltier thermoelectric module.

[0023] Figure 16 shows a variant embodiment, how layers of modules of may be stacked within Peltier thermoelectric module 121a.

[0024] Figure 17 shows how reversing the polarity of the Peltier module is contemplated.

[0025] Figure 18 and Figure 19 respectively show schematic side sectional and plan views illustrating an example of a Peltier element 100z. [0026] Figure 20 shows another example of a heatpipe.

[0027] Figure 21 through Figure 29 shown another example implementation of a cryoprobe system 10z.

[0028] Figure 30 to Figure 35 illustrate an embodiment of a further cryoprobe system 10zA.

DETAILED DESCRIPTION

[0029] An aspect of the specification provides a cryoprobe system includes an elongated heat pipe terminating in a tissue penetrating end, a thermal device mounted to and in thermal communication with a region of the elongated heat pipe that is spaced apart from the tissue penetrating end, and a thermal controller coupled to the thermal device. The cryoprobe system also includes the elongated heat pipe, thermal device and thermal controller being co-operatively configured such that the thermal controller can control the thermal device to alternatively cool and heat the heat pipe to cause the tissue penetrating end of the heat pipe to alternatively cool and heat tissues surrounding tissue penetrating end.

[0030] An aspect of the specification provides a cryoablation needle including: a hollow shaft having a proximal end and a tip at a distal end opposite the proximal end; the tip for insertion into a target site of a patient; at least one working fluid cavity in parallel with the hollow shaft including a capillary structure for capillary action of a working fluid for thermal exchange between the working fluid and the target site; and, a thermoelectric module configured to cycle the working fluid between hot and cold temperatures for cryoablation of the target site.

[0031] An aspect of the specification provides a cryoablation needle, wherein the thermoelectric module includes a Peltier device configured to reverse polarity, enabling the rapid switch between heating and cooling cycles of the working fluid.

[0032] An aspect of the specification provides a cryoablation needle, wherein the working fluid includes one or more of ammonia and methanol. [0033] An aspect of the specification provides a cryoablation needle, wherein the capillary structure includes a plurality of micro-grooves on the inner surface of the working fluid cavity, enhancing the capillary action and thermal exchange efficiency.

[0034] An aspect of the specification provides a cryoablation needle, further including a sensor integrated with the thermoelectric module to monitor the temperature of the working fluid and adjust the cycling speed between hot and cold temperatures accordingly.

[0035] An aspect of the specification provides a cryoablation needle, wherein the hollow shaft is coated with an insulative material to minimize thermal loss to nontarget areas during the cryoablation process.

[0036] An aspect of the specification provides a cryoablation needle, wherein the thermoelectric module is configured to maintain the working fluid at temperatures ranging from about -40°C to about 10°C during the cryoablation cycles.

[0037] An aspect of the specification provides a cryoablation needle, further including a control unit external to the needle, which operates the thermoelectric module based on pre-set cryoablation protocols.

[0038] An aspect of the specification provides a cryoablation needle, wherein the working fluid cavity includes multiple separate cavities arranged parallel to the hollow shaft, each cavity having its own capillary structure to independently manage the temperature at different sections of the needle.

[0039] An aspect of the specification provides a cryoablation needle, wherein the at least one working fluid cavity includes a coaxial arrangement around the hollow shaft, and the capillary structure is integrated within the walls of each cavity to facilitate a uniform temperature distribution around the circumference of the needle.

[0040] An aspect of the specification provides a cryoablation needle, further including a feedback mechanism integrated with the thermoelectric module to dynamically adjust the thermal output based on real-time temperature data received from sensors located at strategic positions along the needle.

[0041] An aspect of the specification provides a cryoprobe system including: an elongated heat pipe terminating in a tissue penetrating end; a thermal device mounted to and in thermal communication with a region of the elongated heat pipe that is spaced apart from the tissue penetrating end; and a thermal controller coupled to the thermal device; the elongated heat pipe, thermal device, and thermal controller being co-operatively configured such that the thermal controller can control the thermal device to alternatively cool and heat the heat pipe to cause the tissue penetrating end of the heat pipe to alternatively cool and heat tissues surrounding tissue penetrating end.

[0042] An aspect of the specification provides a cryoprobe system wherein the thermal device is a thermoelectric device and thermal controller is an electrical control circuit electrically coupled to the thermoelectric device.

[0043] An aspect of the specification provides a cryoprobe system the thermoelectric device includes a plurality of Peltier elements arranged to surround an outer perimeter of the region of the elongated heat pipe.

[0044] An aspect of the specification provides a cryoprobe system wherein the plurality of Peltier elements circumferentially arranged about the outer perimeter of the region of the elongated heat pipe.

[0045] An aspect of the specification provides a cryoprobe system wherein the plurality of Peltier elements are circumferentially arranged in multiple thermally cooperating layers about the outer perimeter of the region of the elongated heat Pipe.

[0046] An aspect of the specification provides a cryoprobe system including a fluid flow conduit in thermal communication with the thermoelectric device and configured for transporting a heat exchange fluid that performs a heat exchange operation with the thermoelectric device. [0047] An aspect of the specification provides a cryoprobe system wherein the thermal device includes a fluid flow conduit wrapped about the region for causing a heat exchange fluid to circulate about the region, the thermal controller including a fluid flow control system for selectively routing hot or cool fluid through the fluid flow conduit.

[0048] An aspect of the specification provides a cryoprobe system wherein the elongated heat pipe, thermal device and thermal controller are co-operatively configured such that the thermal device can alternatively cool and heat the heat pipe to cause the tissue penetrating end of the heat pipe to cycle with a range of minus about 60 degrees Celsius to plus about 60 degrees Celsius.

[0049] An aspect of the specification provides a cryoprobe system wherein the elongated heat pipe, thermal device and thermal controller are co-operatively configured such that the thermal device can alternatively cool and heat the heat pipe to cause the tissue penetrating end of the heat pipe to cycle between minus about 40 degrees Celsius or lower and plus about 40 degrees Celsius or higher.

[0050] An aspect of the specification provides a cryoprobe system wherein the elongated heat pipe, thermal device and thermal controller are co-operatively configured such that the thermal device can alternatively cool and heat the heat pipe at a frequency of at least one heating and cooling cycle about every 120 seconds.

[0051] Figure 1 shows a system for cryoablation indicated generally at 100. System 100 includes an applicator unit 104 that connects to a controller 108.

[0052] The applicator unit 104 includes a needle 116, projecting from a valve body 120, and a pistol grip 124 disposed from valve body 120 at roughly ninety degree angles to the needle 116. An inlet working fluid line 128-1 and an outlet working fluid line 128-2 are disposed on the opposite side of valve body 120 from grip 124. (Collectively, working fluid line 128-1 and working fluid line 128-2 are referred to as working fluid lines 128, and generically, as working fluid line 128. This nomenclature is used elsewhere herein.) [0053] Working fluid lines 128 can be connected to any type of external heating and cooling energy source.

[0054] The configuration of applicator unit 104 is chosen to allow a medical practitioner to control unit 104 so as to direct needle 116 to a target site in a patient, and so the configuration is not particularly limited, but the example shown in Figure 1 represents a presently preferred embodiment at the time of preparation of this specification.

[0055] In a present embodiment, needle 116 is hollow and includes a distal tip 132. Thus a port 136 on valve body 120 is provided to communicate with a channel within valve body 120. The channel within valve body 120, in turn, communicates with the hollow shaft of the needle 116. In other words, port 136 is in communication with distal tip 132 via the channel and hollow shaft of needle 116.

[0056] A stylet 140 can be inserted into the port 136 and through the channel until a distal tip 144 of the stylet 140 aligns with the distal tip 132 of needle 116. Distal tip 144 and distal tip 132, when aligned, provide a contiguous piercing surface during its introduction to the target site 158 of a patient 162. (If it needs saying, the representation of patient 162 and target site 158 in Figure 1 is iconographic and not to scale. Further elaboration about target sites 158 will be discussed in greater detail below).

[0057] It is to be understood that the stylet 140 can be flexible or can be rigid in which case it may be referred to as an obturator. Needle 116 and stylet 140, when combined, may be referred to as a trocar, in which case needle 116 may be referred to as a cannula.

[0058] When stylet 140 is removed, a water line 166 connected to a water source 170 can optionally be connected to port 136 in order to deliver water to target site 158 via distal tip 132. [0059] Controller 108 is configured to provide signals to valve body 120 that direct working fluid to and from needle 116 via lines 128 so as to provide cyclic cooling and heating at the distal tip 132 of needle 116 and effect the cryoablation treatment. Controller 108 can also be used to deliver measured amounts of water from water source 170 when water line 166 is connected to port 136.

[0060] Figure 2 shows a schematic diagram of a non-limiting example of internal components of controller 108. In this example, controller 108 includes at least one input device 204. Input from device 204 is received at a processor 208 which in turn controls at least one output device 212. Input device 204 can be a traditional keyboard and/or mouse and/or touch screen to provide physical input. Likewise output device 212 can be a display and/or speakers. In variants, additional and/or other input devices 204 or output devices 212 are contemplated or may be omitted altogether as the context requires.

[0061] Processor 208 may be implemented as a plurality of processors or one or more multi-core processors. The processor 208 may be configured to execute different programing instructions responsive to the input received via the one or more input devices 204 and to control one or more output devices 212 to generate output on those devices.

[0062] To fulfill its programming functions, the processor 208 is configured to communicate with one or more memory units, including non-volatile memory 216 and volatile memory 220. Non-volatile memory 216 can be based on any persistent memory technology, such as an Erasable Electronic Programmable Read Only Memory (“EEPROM”), flash memory, solid-state hard disk (SSD), other type of hard-disk, or combinations of them. Non-volatile memory 216 may also be described as a non-transitory computer readable media. Also, more than one type of non-volatile memory 216 may be provided.

[0063] Volatile memory 220 is based on any random access memory (RAM) technology. For example, volatile memory 220 can be based on a Double Data Rate (DDR) Synchronous Dynamic Random-Access Memory (SDRAM). Other types of volatile memory 220 are contemplated.

[0064] Processor 208 also connects to a network 236 via a network interface 232, which in turn connects controller 108 to applicator unit 104. Network interface 232 can also be used to connect another computing device that has an input and output device, thereby obviating the need for input device 204 and/or output device 212 altogether.

[0065] Network 236 can be a simple physical cable connecting controller 108 to applicator 104 and nothing else. Network 236 may also be wireless, however, this may not be presently preferred due to the need for very precise control over unit 104 and such control may not tolerate radio frequency interference. Network 236 may also be a combination of wired and wireless, with a wire connecting to controller 104 and wired or wireless connection to a central server 240. Network 236 can thus include the Internet to provide additional network connectivity for controller 108, such as to the central server 240 that can monitor the functioning of unit 104 and/or a plurality of applicator units 104 (not shown) to gather usage data and to periodically adjust algorithms that control applicator units 104. A machine learning algorithm is also contemplated where the historic use of applicator unit 104 or applicator units 104 are used to train algorithms for different cryoablation procedures.

[0066] Programming instructions in the form of applications 224 are typically maintained, persistently, in non-volatile memory 216 and used by the processor 208 which reads from and writes to volatile memory 220 during the execution of applications 224. Various methods for controlling unit 104 discussed herein can be coded as one or more applications 224. One or more tables or databases 228 are maintained in non-volatile memory 216 for use by applications 224. Applications 224 can thus include methods to control unit 104 for different cryoablation procedures, while tables 228 can be used to store different parameters of different levels of temperature levels, cycle times and cycle rates to provide hot and cold temperatures at distal tip 132 of needle 116. Similarly, applications 224 and tables 228 can be used to deliver water from water source 170 to target site 158 according to different cryoablation procedures.

[0067] In Figure 1 , controller 108 is represented in the form factor of a laptop computer that is separate from applicator unit 104, but controller 108 can be implemented in any number of different form factors. For example, in a fully miniaturized version of system 100, controller 108 can be integrated into applicator unit 104, such as through integration into valve body 120 and/or grip 124.

[0068] Referring now to Figure 3, a sectional view of distal tip 132 of needle 116 is shown in greater detail. Stylet 140 is shown as almost completely inserted into the hollow shaft 304 of needle 116. (Note the scale of stylet 140 is exaggerated as the outside diameter of stylet 140 would be typically close to the inner diameter of shaft 304 so that distal tip 144 and distal tip 132 provide a contiguous piercing surface.

[0069] Notably, needle 116 also includes a plurality of working fluid cavities 308. In a present embodiment, two working fluid cavities 308 are shown, namely a first cavity 308-1 and a second cavity 308-2. In other embodiments, only one cavity 308 may be provided, or three, four or more cavities 308 may be provided within the limits of present or future manufacturability and the overall desired diameter of needle 116.

[0070] Each cavity 308 includes a core 312 and a capillary structure 316. The capillary structure 316 can be in the form of a wicking material, or a plurality of grooves, or any other structure that enable capillary action of working fluid along the length of cavity 308 when working fluid is introduced and/or removed as directed by valve body 120 from lines 128.

[0071] Figure 4, Figure 5 and Figure 6 needle 116 and distal tip 132 from different views than Figure 3, but generally include the same elements. Figure 4 is a sectional view according to the lines indicated at Figure 4 in Figure 3. Figure 5 is a sectional view according to the lines indicated at Figure 5 in Figure 3. Figure 6 is a partial perspective sectional view of the view in Figure 3.

[0072] It is to be understood that variations, combinations, and/or subsets of the embodiments discussed throughout are contemplated. For example, needle 116 can be used with additional instruments to allow needle 116 to be introduced to the target site by the Seidinger technique, to recognize that needle 116 may have a relatively large bore and so the Seidinger technique can introduce a relatively small opening into the target site 158 which can then be gently widened to accommodate the relatively larger diameter of the needle 116.

[0073] In another embodiment, a Peltier thermoelectric module may be incorporated into valve body 120 to provide additional heating and cooling of working fluid within cavities 308, beyond the heating and cooling provided via lines 128. In a further embodiment, lines 128 may be obviated using a Peltier thermoelectric module within valve body 120 to provide the energy transfer cycling to the working fluid for cavities 308. In another embodiment, lines 128 do not carry actual working fluid for cavities 308 only provide supplementary heating and cooling for the Peltier thermoelectric module, and the working fluid is entirely maintained within valve body 120 and is primarily heated and cooled by the Peltier thermoelectric module. The use of a Peltier thermoelectric module and/or external heating and cooling sources for lines 128 can be chosen according to the desired temperature operating ranges and cycle times at distal tip 132, taking into consideration any water that may or may not be introduced from water source 170.

[0074] Figure 7 shows a system for cryoablation indicated generally at 100a. System 100a is a variant on system 100 and so like elements bear like references except followed by the suffix “a”. System 100a includes a main unit 704a that houses the controller 108a as well as a heat exchanger for delivering coolant along lines 128a to applicator unit 104a. Main unit 704a can also incorporate water source 170. [0075] Main unit 704a can implement a high-efficiency cooling mechanism to manage heat in the tethered console, ensuring stable operation even under heavy usage. Main unit 704a can feature temperature control systems that continuously monitor and adjust internal temperatures, maintaining optimal performance and preventing overheating.

[0076] In system 100a, valve body 120a is omitted in favour of a Peltier thermoelectric module 121a. Peltier thermoelectric module 121a itself provides the working fluid for fluid cavities 308 (not shown) of needle 116a.

[0077] Lines 128a carry power to Peltier thermoelectric module 121a, and the cycling of electrical power by main unit 704a to peltier thermoelectric module 121a can be used to effect a cryoablation treatment cycle.

[0078] In other embodiments, lines 128a may also be provided with coolant lines in addition to, or in lieu of power, to provide supplementary heating and cooling for Peltier thermoelectric module 121a. Peltier thermoelectric module 121a can thus implement a high-efficiency liquid cooling mechanism cooperate with larger- scale heating and cooling functions in the tethered console of main unit 704a, to provide substantially stable operation of system 100a even under heavy usage.

[0079] In general, combined with controller 108, main unit 704a features a robust temperature control system that can continuously monitor and adjust internal temperatures of needle 116a (and/or its variants) to manage performance while reducing or eliminating likelihood overheating. Main unit 704a can provide power and/or coolant to Peltier thermoelectric module 121a, according to the design choice of a person skilled in the art.

[0080] Table I shows an example list of temperatures over time that can be achieved at distal tip 132a (without a resistive load of target site 158) using system 100a.

TABLE I

be made in the following gauges: 13, 12, 11, 10, 9, or 8 gauge. Other gauges can be provided based on desired heat transfer properties and the nature of a target site 158. If used with the Seidinger technique, then guide wires can have a diameter of about 0.14 mm, 0.18mm, 0.22mm, 035mm, and 0.38mm.

[0082] Within a 13 G needle it can be preferred to have one heat pipe (aka working fluid cavity). Within a 11G or 12 G needle it can be preferred to have one or two heat pipes. Within 10G needle it can be preferred to have two or three heat pipes. Within a 9G or 8 G needle it can be preferred to have two or three or four heat pipes. Despite these preferences, it is to be understood that the particular ratio of needle diameter or gauge to the number of heat pipes can be chosen based on manufacturing limitations and desired heat transfer properties.

[0083] It is to be understood that a plurality of needles can be included in a system, such as system 100 or system 100a. The plurality of needles 116 may be used in parallel to treat a particular target site 158. A target site may also include a plurality of sites, such as a rib cage. In the case of multiple rib fractures or bruising, a plurality of needles 116 may be deployed to a plurality of target sites or rib locations to allow for parallel cryoablation techniques.

[0084] Figure 8 shows a cross section of a needle 116b in accordance with another embodiment. Needle 116b is a variant of needle 116 and thus like characters bear like references except followed by the suffix “b”. In Figure 8, needle 116b contemplates a hollow shaft 304b that is functionally and structurally substantially equivalent to shaft 304. Needle 116b also contemplates a single working fluid cavity 308b that coaxially surrounds shaft 304b. Cavity 308b includes a core 326b surrounded by an outer capillary structure 316b-1 adjacent to the outer wall 804b of needle 116b, and an inner capillary structure 316b-2 that surrounds shaft 304b. Cavity 308b thus carries working fluid, aided by capillary structures 316b. in order to control the temperature of the distal tip of needle 116b.

[0085] Shaft 304b can thus carry water and/or pass a stylet (not shown) and/or guidewire (not shown) of a diameter of between about 0.36mm and about 0.41 mm.

[0086] Figure 9 depicts the placement of needle 116b during insertion into a target site, specifically an intercostal space 900 located between a first rib 908-1 and a second rib 908-2. Figure 9 shows the alignment of the needle in a minimally invasive procedure aimed at targeting nerve fibers for temporary pain relief. (Figure 9 is also applicable to variants on needle 116b, including needle 116 and needle 116a.) The intercostal space 900, positioned between the ribs 908, serves as a suitable site for accessing the nerve pathways along the rib cage, crucial for managing thoracic pain. [0087] As illustrated, needle 116b is positioned to administer cryoablation therapy, inducing a second-degree nerve injury by cooling the target area to temperatures between -20°C and -70°C. This controlled injury, achieved through a series of freeze-thaw cycles, is designed to temporarily deactivate the nerve fibers. The method can be effective in disrupting pain signaling without causing permanent damage, allowing the nerve to regenerate over a period of 6-8 weeks. Through this procedure, needle 116b facilitates pain relief by altering the nerve's capacity to transmit pain signals, thereby impacting pain at its physiological source.

[0088] Figure 10 shows a prior art side sectional schematic view of another needle 116c. Needle 116-PA operates based on the Joule-Thomson effect, employing a closed-loop system that contains a cryogen such as liquid nitrogen, argon gas, or CO2. Figure 10 shows the formation of an iceball 1004 at the distal tip needle 116-PA for cryoablation therapy. Needle 116-PA includes a hollow shaft 304-PA which delivers warm cryogen 1008 (i.e. a cryogen at a first temperature, typically in gaseous form) towards the distal tip of needle 116-PA. Hollow shaft 304-PA is surrounded by a hollow cavity 308-PA which carries cool cryogen 1012 (i.e. the cryogen at a second temperature that is lower than the first temperature)

[0089] The interior structure of needle 116-PA shows the flow dynamics. Hollow shaft 304-PA is in communication with hollow cavity 308-PA via a JT (Joule- Thomson) nozzle 1016, through which the cryogen undergoes a controlled expansion from high pressure to low pressure. This expansion allows the cryogen to absorb heat from the surrounding tissue, thereby reducing the temperature sharply at the tip of the needle 116-PA to form iceball 1004.

[0090] In addition to the size and complexity issues of systems involved with prior art needle 116-PA, there are other economic and operational challenges that complicate their use in clinical settings. Firstly, the significant procedural costs associated with the ongoing need for a continuous supply of cryogens for needle 116-PA, such as liquid nitrogen, helium, or liquid argon, are noteworthy. These cryogens are not only costly but also require frequent replenishment. Furthermore, cryoablation devices including needle 116-PA require dedicated storage and handling facilities for these cryogens, adding logistical challenges. Such requirements demand additional space within healthcare settings, which may not always be readily available and therefore limit the availability of cryogenic treatments. Additionally, the handling of volatile gases inherent can pose substantial risks. Any leaks or malfunctions can lead to pressure-related hazards, thus jeopardizing both patient safety and operational integrity.

[0091] Thus, needle 116, needle 116a and needle 116b can all mitigate at least some of the disadvantages of the prior art including needle 116-PA. Figure 11 shows a schematic representation of another needle 116c, a further variant on needle 116, needle 116a and needle 116b that can also mitigate disadvantages of needle 116-PA. Figure 12 shows a cross section of needle 116c as labelled in Figure 11.

[0092] As best seen in Figure 11 , needle 116c includes distal tip 132c, which is inserted into the target area of a patient. Needle 116c can be based on a heatpipe with a closed loop of working fluid. Needle 116c includes a hollow shaft 304c surrounded by a capillary structure 316c. As indicated at “1” in Figure 11 , at tip 132c the working fluid within the capillary structure 316c absorbs heat from the target site surrounding distal tip 132c. The relatively warmer working fluid then moves into cavity 304c, where, as indicated at “2”, it flows towards the proximal end of needle 116c, opposite to distal tip 132c. When needle 116c is implemented as a variant on needle 116, then the heat in the working fluid can be absorbed by valve body 120 (not shown in Figure 11), as indicated at “3” in Figure 11. Alternatively, when needle 116c is implemented as a variant on needle 116a then the heat in the working fluid can be absorbed by Peltier thermoelectric module 121a (not shown in Figure 11), as indicated at “3” in Figure 11. As indicated at “4”, the now-cooled working fluid passes back into capillary structure 316c where the working fluid again travels to distal tip 132c for the cycle to repeat. The opposite cycle is used to heat the target site surrounding the distal tip. [0093] Figure 13 shows a graph of the test results from Table I, from utilizing needle 116c with Peltier thermoelectric module 121a. The results showed High reversibility, allowing for rapid tissue freezing and thawing within the same procedure, providing greater control and adaptability during treatment.

[0094] Figure 14, Figure 15, Figure 16 and Figure 17 help further elaborate on Peltier thermoelectric module 121a.

[0095] Figures 14 and 15 illustrate the Peltier module 121a in greater detail, highlighting its role achieving cryogenic temperature-cycling for cryoablation. The Peltier module 121a functions as a small semiconductor device designed for temperature control within the overall system. The structure of the module includes alternate legs 1404 of P-type and N-type semiconductors, which are arranged in a matrix to facilitate temperature modulation. These semiconductor legs 1404 are sandwiched between thermally conductive ceramic plates 1408, which help in dissipating heat efficiently and maintaining the structural integrity of the module. A temperature difference necessary for the cryoablation process is created by an electric current that flows through these semiconductors, enabling the module to rapidly alternate between heating and cooling.

[0096] Figure 16 shows a variant embodiment, how layers of modules of may be stacked within Peltier thermoelectric module 121a. Figure 16 shows a multilayered arrangement of Peltier modules that creates a cascading temperature effect, progressively lowering the temperature to cryogenic levels. Different electrical configurations can be provided between layers to improve or maximize the temperature differential in order to sustain cryogenic temperatures.

[0097] Figure 17 shows how reversing the polarity of Peltier module 121a is contemplated, which switches their function from cooling to heating, enabling efficient freeze-thaw cycles in cryoablation and rapid transitions between freezing and thawing improves cryoablation performance,

[0098] By way of context, a Peltier element will be briefly disclosed. As known in the art, Peltier elements functions via the Peltier effect, where heat is absorbed or emitted when an electric current is passed through a junction of two different materials. Figure 18 and Figure 19 respectively show schematic side sectional and plan views illustrating an example of a Peltier element 100z that is formed by a series of P- and N-doped pellets coupled together via electrical connectors 110z (e.g, copper tabs). The illustrated Peltier element 100z comprises a pair of thin electrically insulating, thermally conductive wafers 104z, 102z (for example, wafers can be formed from ceramic or other electrically insulating material) between which the P- and N-doped pellets are sandwiched. The wafers 104z, 102z provide electrical insulation. The N-type pellets have an excess of electrons, while the P-type pellets has a deficit of electrons. The doped materials are preferably composed of bismuth-telluride semiconductor material.

[0099] The free (bottom) end of the P-type pellet is connected to a first potential 106z and the free (bottom) end of the N-type pellet is connected to a second potential 108z ground. In the case where first potential 106z is a positive potential and second potential 108z is a negative or ground potential, the positive charge carriers (i.e., the holes) in the P-type pellets are repelled by the positive voltage potential and attracted by the negative pole, whereas the negative charge carriers (electrons) in the N-type pellets are repelled by the negative potential and attracted by the positive pole. As the electrons move from a P-type pellet to an N- type pellet through an electrical connector 110z, the electrons jump to a higher energy state, thereby absorbing thermal energy on the side of that is shown at the bottom in Figure 18. Continuing through the lattice of material, the electrons flow from an N-type pellet to a P-type pellet through an electrical connector 110z, dropping to a lower energy state and releasing energy as heat. Reversing the polarity of first potential 106z and second potential 108z will cause the heat generating heat absorbing sides of Peltier element 100z to be reversed.

[00100] This, in operation, when an electric current is applied across the Peltier element 100z, heat is absorbed from one side of the Peltier module (the "cold" side) and emitted on the opposite side (the "hot" side), thereby creating a temperature difference across each Peltier module. In one example embodiment, as described below, this process is effectively multiplied with the stacking of Peltier elements.

[00101] By way of further context, a brief summary of a heat pipe 200z will be provided with reference to Figure 20. Heat pipes can be used as passive heat transfer components. They leverage phase transition to efficiently transfer thermal energy from one point to another. Heat pipe 200z comprises a hollow enclosure that is hermetically sealed. The enclosure is typically made from a thermally conductive metallic material (such as copper or aluminum or stainless steel), which provides high thermal conductivity and good mechanical strength. The heat pipe 200z includes a working fluid, contained within the enclosure. The working fluid can be selected based on the operational temperature range of the heat pipe. For instance, water, ethanol, or ammonia can be employed as the working fluid. The fluid is contained in an amount sufficient to enable phase transition (evaporation and condensation) within the operational temperature range of the heat pipe. The heat pipe 200z also comprises a wick structure that lines the inner surface of the enclosure. The wick structure can be made of a porous material, which enables capillary action for the return of the condensed working fluid from the condenser end to the evaporator end of the heat pipe.

[00102] In operation, when heat is applied to one end (e.g., the evaporator end) of the heat pipe, the working fluid absorbs the heat and evaporates. The generated vapor travels to the opposite end (e.g., the cooler condenser end) of the heat pipe, where it releases the heat and condenses back into the liquid phase. The condensed fluid then returns to the evaporator end via capillary action provided by the wick structure, completing the cycle and enabling continuous heat transfer.

[00103] With reference to Figure 21 through Figure 28, in one example implementation of the present disclosure, a cryoprobe system 10z is disclosed that includes an elongated heat pipe 300z terminating in a tissue penetrating end 302z. The cryoprobe system 10z includes a thermal device in the form of a Peltier thermoelectric device 304z mounted to and in thermal communication with a region 306z of the elongated heat pipe 300z that is spaced apart from the tissue penetrating end 302z, and a thermal controller 31 Oz coupled to the Peltier thermoelectric device 304z. The elongated heat pipe 300z, Peltier thermoelectric device 304z and thermal controller 31 Oz are co-operatively configured such that the thermal controller 31 Oz can control the Peltier thermoelectric device 304z to alternatively cool and heat the heat pipe to cause the tissue penetrating end 302z of the heat pipe to alternatively cool and heat tissues surrounding tissue penetrating end. Thermal controller 31 Oz can be an electrical control circuit electrically coupled to provide power to the Peltier thermoelectric device 304z. A temperature sensor 314z positioned at the tissue penetrating end 302z is operatively connected to provide a sensed temperature signal to the thermal controller 31 Oz.

[00104] In the illustrated example, the cryoprobe system 10z also includes a cooling system 312z that is configured to supply and remove a cooling fluid (for example, air or other cooling fluid) to the Peltier thermoelectric device 304z. As best seen in Figures 23, 26 and 27, the cooling system 312z can include at least one helical fluid conduit 316z that surrounds the Peltier thermoelectric device 304z. The helical fluid conduit 316z can be in fluid communication with a fluid flow inlet tubbing 320z and outlet tubing 322z that are respectively connected to a cooling fluid source and sink. In the illustrated example, the cooling system 312z can include a helically grooved inner component 318z that is surrounded by an outer housing of shield 320z that collectively define the helical fluid conduit 316z.

[00105] In the illustrated example, the hermetically sealed hollow enclosure that defines heat pipe 300z can be formed from surgical grade steel and has a diameter that enables the tissue penetrating end 302z to function as an probe that can be inserted through skin and into the internal tissue of a patient to perform cryoneurolysis. In some examples, tissue penetrating end 302z of heat pipe 300z can be chamfered to facilitate insertion. In some examples, heat pipe 300z will be substantially rigid to enable insertion into patient tissue to occur. In some examples, heat pipe 300z may have a degree of flexibility to enable it to be guided within tissue to a treatment location.

[00106] In example embodiments, the elongated heat pipe 300z, Peltier thermoelectric device 304z and thermal controller 31 Oz are co-operatively configured such that the tissue penetrating end 312z of the heat pipe can be controlled to cycle with a range of minus 60 degrees Celsius to plus 60 degrees Celsius. In example embodiments, the elongated heat pipe 300z, Peltier thermoelectric device 304z and thermal controller 31 Oz are co-operatively configured such that the tissue penetrating end 312z of the heat pipe can be controlled to cycle between a low of at least minus 40 degrees Celsius and a high of plus 40 degrees Celsius. In example embodiments, the elongated heat pipe 300z, Peltier thermoelectric device 304z and thermal controller 31 Oz are cooperatively configured such that repeated cooling and heating cycles can be carried out with an operating cycle period of 60 second to 120 seconds. In some, examples, operating cycle period is user configurable, along with maximum and minimum temperatures. Hot/cold operating cycle period, the respective durations of hot and cold time within such period, and the hot and cold temperatures are features that can be selected based on the application.

[00107] These temperatures and cycle times are illustrative and other temperature ranges and cycle durations are possible.

[00108] Figure 29 shows an end sectional view of heat pipe 300z surrounded by Peltier thermoelectric device 304z. In the illustrated example, heat pipe 300z has a circular cross-section and the Peltier thermoelectric device 304z extends as an annular, ring-like structure around the round outer perimeter (e.g., circumference) of the heat pipe 300z for the axial length of heat pipe region 306z. An electrically insulative, thermally conductive layer (e.g., wafer 102z) is provided between the Peltier thermoelectric device 304z and the heat pipe 300z. In the illustrate example, Peltier thermoelectric device 304z is a multi-stage or stacked module that is formed a first or inner layer 100z-1 of circumferentially arranged Peltier elements 100zA, 100zB, 100zC, etc, that are arranged side by side and extend around the circumference of the heat pipe 300z. The Peltier elements 100zA, 100zB, 100zC are electrically connected in series or parallel. In some examples, the individual Peltier elements 100zA, 100zB, 100zC are contoured to maximize contact contact the outer surface of the heat pipe. For example, the individual Peltier thermoelectric device 304z is a multi-stage or stacked module that is formed a first or inner layer 100z-1 of circumferentially arranged Peltier elements 100zA, 100zB, 100zC, etc, that are arranged side by side and extend around the circumference of the heat pipe 300z. are each shown as individual arc-shaped elements in the Figures. A second stage or layer of Peltier thermoelectric device 304z is formed by an outer layer 100z-2 of circumferentially arranged Peltier elements 100zD, 100zE, 100zF, etc, that are arranged side by side and extend around the outer circumference of the first layer 100z-1 of circumferentially arranged Peltier elements 100zA, 100zB, 100zC, etc,. In example embodiments, the Peltier elements of all layers are collectively electrically connected and controllable by thermal controller 31 Oz such that all Peltier elements can be controlled to all simultaneously have their respective cool sides facing the heat pipe 300z during a cooling portion of an operating cycle of the system 10z and to all simultaneously have their respective hot sides facing the heat pipe 300z during a heating portion of the operating cycle. The electrically insulative, thermally conductive layer located between the inner layer 100z-1 of circumferentially arranged Peltier elements 100zA, 100zB, 100zC may physically connect the elements of the layer together in some examples.

[00109] Although Peltier thermoelectric device 304z has been described above the thermal device for heating and cooling the heat pipe 300z, in alternative examples different thermal devices can be used for providing heating and cooling to heat pipe 300z. By way of example, Figure 30 to Figure 35 illustrate an embodiment of a further cryoprobe system 10zA that operates in a manner similar to cryoprobe system 10z except that Peltier thermoelectric device 304z has been replaced with fluid bused heat exchanging thermal device 404z that comprises a helical fluid passage 406z defined by tubing that is wrapped around region 306z of the heat pipe 300z. A thermal insulating sleeve 408z may be formed over the tubing. Thermal controller 41 Oz takes the form of a control circuit and valve arrangement that can alternatively provide hot or cold fluid, via tubing inlet and outlets 412z, 41 Oz to the helical fluid passage 406z. By such means, the thermal device 404z can be controlled to effect heating and cooling at the tissue penetrating end 302z of the heat pipe 300z to alternatively cool and heat tissues surrounding tissue penetrating end. Water, glycol or other suitable fluid can be used as the heat transfer fluid that is provided through helical fluid passage 406z.

[00110] Although heat pipe 300z has been shown as having a circular cross- sectional area, heat pipe 300z could take any number of hollow, sealed tubular configurations. For example, heat pipe 300z could have an oval cross-sectional area or a rectangular cross-sectional area. In some examples, multiple adjacent heat pipes with tissue penetrating ends could be included in the system.

[00111] In some examples, heat pipe 300z is disposable and can be removably inserted into the thermal device 304z, 404z to enable low cost replacement between procedures.

[00112] A person skilled in the art will now appreciate that the teachings herein can provide a relatively compact and efficient means of providing cryoablation therapies relative to the prior art.

[00113] It should be recognized that features and aspects of the various examples provided above can be combined into further examples that also fall within the scope of the present disclosure. In addition, the figures are not to scale and may have size and shape exaggerated for illustrative purposes.

Claims

1. A cryoablation needle comprising: a hollow shaft having a proximal end and a tip at a distal end opposite the proximal end; the tip for insertion into a target site of a patient; at least one working fluid cavity in parallel with the hollow shaft including a capillary structure for capillary action of a working fluid for thermal exchange between the working fluid and the target site; and, a thermoelectric module configured to cycle the working fluid between hot and cold temperatures for cryoablation of the target site.

2. The cryoablation needle of claim 1 , wherein the thermoelectric module comprises a Peltier device configured to reverse polarity, enabling the rapid switch between heating and cooling cycles of the working fluid.

3. The cryoablation needle of claim 2, wherein the working fluid includes one or more of ammonia and methanol.

4. The cryoablation needle of any preceding claim, wherein the capillary structure includes a plurality of micro-grooves on the inner surface of the working fluid cavity, enhancing the capillary action and thermal exchange efficiency.

5. The cryoablation needle of any preceding claim, further comprising a sensor integrated with the thermoelectric module to monitor the temperature of the working fluid and adjust the cycling speed between hot and cold temperatures accordingly.

6. The cryoablation needle of any preceding claim, wherein the hollow shaft is coated with an insulative material to minimize thermal loss to non-target areas during the cryoablation process.

7. The cryoablation needle of any preceding claim, wherein the thermoelectric module is configured to maintain the working fluid at temperatures ranging from about -40°C to about 10°C during the cryoablation cycles.

8. The cryoablation needle of any preceding claim, further comprising a control unit external to the needle, which operates the thermoelectric module based on pre-set cryoablation protocols.

9. The cryoablation needle of any preceding claim, wherein the working fluid cavity comprises multiple separate cavities arranged parallel to the hollow shaft, each cavity having its own capillary structure to independently manage the temperature at different sections of the needle.

10. The cryoablation needle of any preceding claim, wherein the at least one working fluid cavity includes a coaxial arrangement around the hollow shaft, and the capillary structure is integrated within the walls of each cavity to facilitate a uniform temperature distribution around the circumference of the needle.

13. The cryoablation needle of any one of claims 2-10, further comprising a feedback mechanism integrated with the thermoelectric module to dynamically adjust the thermal output based on real-time temperature data received from sensors located at strategic positions along the needle.

14. A cryoprobe system comprising: an elongated heat pipe terminating in a tissue penetrating end; a thermal device mounted to and in thermal communication with a region of the elongated heat pipe that is spaced apart from the tissue penetrating end; and a thermal controller coupled to the thermal device; the elongated heat pipe, thermal device, and thermal controller being cooperatively configured such that the thermal controller can control the thermal device to alternatively cool and heat the heat pipe to cause the tissue penetrating end of the heat pipe to alternatively cool and heat tissues surrounding tissue penetrating end.

15. The cryoprobe system of claim 14 wherein the thermal device is a thermoelectric device and thermal controller is an electrical control circuit electrically coupled to the thermoelectric device.

16. The cryoprobe system of claim 15 the thermoelectric device comprises a plurality of Peltier elements arranged to surround an outer perimeter of the region of the elongated heat pipe.

17. The cryoprobe system of claim 16 wherein the plurality of Peltier elements circumferentially arranged about the outer perimeter of the region of the elongated heat pipe.

18. The cryoprobe system of claim 16 wherein the plurality of Peltier elements are circumferentially arranged in multiple thermally cooperating layers about the outer perimeter of the region of the elongated heat pipe.

19. The cryoprobe system of claim 15 comprising a fluid flow conduit in thermal communication with the thermoelectric device and configured for transporting a heat exchange fluid that performs a heat exchange operation with the thermoelectric device.

20. The cryoprobe system of claim 14 wherein the thermal device comprises a fluid flow conduit wrapped about the region for causing a heat exchange fluid to circulate about the region, the thermal controller including a fluid flow control system for selectively routing hot or cool fluid through the fluid flow conduit.

21. The cryoprobe system of claim 14 wherein the elongated heat pipe, thermal device and thermal controller are co-operatively configured such that the thermal device can alternatively cool and heat the heat pipe to cause the tissue penetrating end of the heat pipe to cycle with a range of about minus 60 degrees Celsius to about plus 60 degrees Celsius.

22. The cryoprobe system of claims 14 wherein the elongated heat pipe, thermal device and thermal controller are co-operatively configured such that the thermal device can alternatively cool and heat the heat pipe to cause the tissue penetrating end of the heat pipe to cycle between minus about 40 degrees Celsius or lower and plus about 40 degrees Celsius or higher.

23. The cryoprobe system of any one of claims 14 wherein the elongated heat pipe, thermal device and thermal controller are co-operatively configured such that the thermal device can alternatively cool and heat the heat pipe at a frequency of at least one heating and cooling cycle about every 120 seconds.