WO2015193892A1

WO2015193892A1 - Illumination device for cholecystectomy

Info

Publication number: WO2015193892A1
Application number: PCT/IL2015/050610
Authority: WO
Inventors: Muhamad ADILA; Yaakov Nahmias; Asher SABAN; Gahl LEVY
Original assignee: Hadasit Medical Research Services and Development Co; Yissum Research Development Co of Hebrew University of Jerusalem
Current assignee: Hadasit Medical Research Services and Development Co; Yissum Research Development Co of Hebrew University of Jerusalem
Priority date: 2014-06-16
Filing date: 2015-06-16
Publication date: 2015-12-23
Anticipated expiration: 2016-12-16

Abstract

A system for aiding in the successful performance of laparoscopic cholecystectomy, by improving the optical identification of the elements of the bile duct system. The identification system utilizes the differential absorption of light in bile products, as compared with its absorption in blood based tissues. The bile bearing vessels can thus be distinguished optically from surrounding tissues and vessels. The region of the operation is imaged in the 600-700 nm range, where bile absorbs more strongly than blood, such that the bile-bearing vessels appear substantially darker than the surrounding tissues. The illuminated region is imaged by a laparoscopic camera system. The desired spectral region can be selected either by using illumination having that selected spectral range, or by using a camera sensitive to that spectral range. The spectral range can be selected by use of optical passband filters disposed either on the illuminating system or on the camera.

Description

ILLUMINATION DEVICE FOR CHOLECYSTECTOMY

FIELD OF THE INVENTION

The present invention relates to the field of laparoscopic cholecystectomy, especially to systems that reduce the likelihood of bile duct injury.

BACKGROUND

Laparoscopic cholecystectomy (LC) has become the standard of care for gallbladder removal, replacing open cholecystectomy. It is widely used in the treatment of cholelithiasis for its benefits of minimal invasiveness.

In a laparoscopic cholecystectomy procedure, several 0.5-1 cm incisions or ports are made in the abdomen, into each of which a trocar is inserted. At the beginning of the procedure, the abdomen is inflated with carbon dioxide gas to provide a working and viewing space for the surgeon. Specialized grasping and cutting instruments and a fiber optic laparoscope are passed through the trocars for the procedure. The laparoscope illuminates the tissue with white light and transmits images from the abdominal cavity to high-resolution video monitors in the operating room. As the operation continues, the surgeon grasps the gallbladder and exposes Calot's Triangle. Calot's Triangle is named after Jean-Frangois Calot. Calot's original description of the triangle in 1891 , was for an anatomic space bordered by the common hepatic duct medially, the cystic duct laterally/inferiorly and the cystic artery superiorly (not the inferior border of the liver as is commonly believed). The slightly larger area bound by the cystic duct, the common hepatic duct, and the liver margin is known as the Hepatocystic triangle.

After the cystic duct and cystic artery are identified, they are clipped. The gallbladder can then be carefully disconnected from the liver and removed from the body through one of the ports.

However, although this step by step procedure sounds simple, because of the nature of the anatomy within the region of Calot's triangle, it can be a formidable experience for the surgeon to perform successfully, because of the crowded surroundings and the proximity of sensitive organs and vessels. Calot' s triangle contains the cystic artery, but may also contain an accessory right hepatic artery or anomalous sectoral bile ducts. Furthermore, it has been estimated that the classically described anatomy of the biliary tree is present in only 30% of patients, such that anomalous structures and aberrant anatomy of the cystic and hepatic ducts and their junctions are the rule rather than the exception (paraphrased from Maingot's Abdominal Operations), and the viewed structure must therefore first be resolved. All of these vessels are surrounded by tendons, sinews, and other connecting tissue. Additionally, any inflammation of the gall bladder, of the Calot's triangle region or of hepatoduodenal ligament areas, resulting in edema, swelling or fibrosis, can make the identification process even more difficult. As a result until the lateral-most structures have been cleared and identification of the cystic duct is definitive, the surgeon should be wary of dissection in the triangle of Calot. According to SESAP 12 (published by the American College of Surgeons) dissection in the triangle of Calot is the most common cause of common bile duct injuries. The success of the LC procedure is thus highly dependent on the skill and experience of the surgeon, and his knowledge and awareness of the bile duct system and surrounding organs of the specific patient. Therefore, any system which can assist the surgeon in identifying the bile duct system will be advantageous to the successful performance of the procedure.

Although the incidence of bile duct injury is estimated to be no more than 0.6%, an estimated 97% of injuries during the LC procedure are caused due to misidentification of biliary anatomy. Such injuries are generally difficult to repair, often involving open surgery, such as when damage to the hepatic artery is caused. Also, hepatic bile is very toxic, such that bile leakage due to unintended duct injury can potentially cause serious infections, colestatis of the liver, and even end stage liver disease. Therefore, although the incidence of bile duct injury is low, the consequences can be very severe.

One common prior art method of identifying structures in the common bile duct (CBD) region is by the practice of intra-operative cholangiography (IOC). However, this involves the use of X-ray radiation to the patient, and the concomitant marginal exposure of the medical staff, and in some cases, an allergic reaction of the patient to the contrast materials used. Another method is an optical imaging method using an agent which is injected into the blood stream and which is broken down in the liver to a fluorescent, luminescent or phosphorescent material. Such breakdown products can be detected optically in the bile ducts about half an hour after the injection. However, this half-hour delay is costly in terms of operating room occupation, and in the additional total time per procedure, that otherwise averages only about twenty to thirty minutes. Furthermore, only very weak intensity is available for identifying the bile ducts since, at least in the case of fluorescence, the quantum efficiency of the fluorescent material is only a few percent at most, meaning that only that percentage of the exciting incident light is returned to the camera to be imaged in order to locate the biliary tree. That low return of light is furthermore limited to the signal generated in the layers of tissue into which the incident light manages to penetrate.

An alternative method of positively identifying the cystic and common bile ducts is described in US Patent Application published as US 2012/0271114 to Y-C. Chang et al, for "Choledochoilluminating Drainage Device". There is described therein a drainage device which includes a catheter incorporating an optical fiber with a light emitting structure at its distal end. When the catheter is inserted into the bile duct, light from the light-emitting structure passes through the walls of the duct, and the path of the duct can thus be clearly identified by a laparoscopic camera disposed to image the CBD region. This device uses light having a wavelength of between 520 and 540 nm, which is in the green part of the spectrum. However, this device is described as requiring either an incision in the gall bladder in order to gain access to the bile duct, or needs to be carefully inserted endoscopically via the stomach into the common bile duct from the opening in the sphincter of Oddi in the duodenum, taking care not to enter the pancreatic duct.

In view of the possible disadvantages of the prior art systems and methods, there therefore exists a need for a surgical system for decreasing the risk of accidental duct injuries during laparoscopic gallbladder excision surgery, and which overcomes at least some of the disadvantages of prior art systems and methods.

The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety. SUMMARY

The present disclosure describes new exemplary systems and methods for aiding in the successful performance of laparoscopic cholecystectomy, by more clearly identifying the elements of the bile duct system to the surgeon, thus reducing the likelihood of bile duct injury. The identification system utilizes the differential light absorption in bile products, as compared with its absorption in hemoglobin and other blood based tissues, or fat tissues. By this means, the bile bearing vessels can be readily distinguished optically from the surrounding adipose and vascular tissue. Bile shows a significant absorption peak in the red, ranging from about 600 to 700 nm, and centered at a wavelength of around 650 nm, while blood is essentially transparent at red wavelengths beyond 610 nm. Therefore, by illuminating or viewing the region of the operation in the 600-700 nm range, the bile- bearing vessels appear substantially darker in the camera image than the surrounding tissues, and can thus be more readily and clearly identified than those surrounding tissues and vessels. In prior art white light illumination systems, the entire region appears to have a monotonous miscellany of similar shades of red, making this identification procedure more difficult.

There are two ways in which this preferential imaging can be performed. According to a first method, the region is illuminated with a conventional broadband white light source, and the camera is equipped with a band pass filter within the approximately 600-700 nm range, allowing for the visible differentiation of the biliary tree in the camera images due to absorption. According to a second method, the region is illuminated with light within the approximately 600-700 nm range, and a conventional broadband visible light imaging camera is used. In the second method, light in the 600-700 nm range can be produced using a band pass filter mounted on a white light source, or alternatively a specific wavelength light source emitting within that band. Such a specific wavelength light sources are light emitting diodes (LED) or laser diodes. An advantage of these systems is that the detection technology can be implemented using current laparoscopic equipment, with the above mentioned modifications to utilize the defined spectral range for the images.

There are also different illumination configurations which can be used for the imaging process, regardless of which of the two above -described methods of spectral discrimination is used. The simplest configuration is to illuminate the region of interest frontally, and to image the frontally reflected light from the region. Though this is the simplest configuration, it is also the least effective, since only a few percent of the incident light is reflected, and that too is reflected only from the surface or close-to-surface layers of the operation region. The most effective illumination configuration is to use backlit illumination from the rear of the region. In this configuration, all of the light imaged passes through the tissues and the vessels of interest, and the spectral discrimination is thus maximal, providing the highest contrast images. However, this configuration is difficult to implement in practice, because the adjacent organs make it difficult, if at all possible, to position the light source behind vessels or organs within the region of the triangle of Calot. Use of a fiber optical light emitter, or a miniature LED device, may make this configuration feasible. The third configuration uses side illumination. This configuration has the advantage of ease of positioning of the light source in the abdominal cavity, coupled with at least some of the advantages of imaging light transmitted through the organs and vessels, rather than reflected therefrom. Of the light incident laterally on the region of interest, part of it is diffusively reflected at oblique angles, but part of it penetrates the organs or vessels, and can then be viewed as dispersed light from the interior of the tissue or vessels, with the associated contrast advantages which imaging of such transmitted light provides.

The systems and methods of the present application thus have the advantages over prior art illumination systems and methods in that:

(i) They can use available laparoscopic camera to view the absorption of the light;

(ii) They can use available strong white light sources to provide higher contrast images; and

(iii) The luminous efficiency is high since all the incident light within the wavelength band selected is used in the imaging process.

The systems and methods of this disclosure can be characterized in that the optical imaging system is adapted to selectively generate images of the surgical region of interest within a limited and preselected spectral range. This limited and preselected spectral range is generically described in this disclosure, and may be thuswise claimed, in two different ways - either in that the optical system has increased sensitivity or responsivity over that range, or that it has reduced sensitivity or responsivity outside of that spectral range. It is to be understood that these two ways of describing the spectral response of the system are intended to be optically equivalent, and no patentable distinction is intended by these different manners of description.

There is thus provided in accordance with an exemplary implementation of the devices described in this disclosure, a laparoscopic system for identifying elements of a biliary tree of a subject in the performance of laparoscopic cholecystectomy, the system comprising an optical system adapted to provides images of a region in which the biliary tree is situated, the optical system comprising:

(i) an illuminating source projecting illumination onto the region, and

(ii) an imaging system adapted to generate images of the illuminated region,

wherein the optical system has reduced sensitivity outside of a spectral range where the optical absorption of the contents of the bile tree is substantially higher than that of surrounding tissues.

In such a system, the illuminating source may have an emittance primarily in the wavelength region of between 600 and 700 nanometers, thereby generating the spectral range where the sensitivity of the optical system is not reduced. In such a case, the illuminating source may comprise a broadband source and a filter having a passband in the wavelength region of between 600 and 700 nanometers. In certain implementations, the illuminating source may comprise either a Light Emitting Diode or a laser diode having emittance in the wavelength region of between 600 and 700 nanometers.

Any of the above described systems may further comprise a fiber optical assembly for conveying the illumination onto the region, and this fiber optical assembly may advantageously be integral to a laparoscopic surgical instrument. In that case, the fiber optical assembly may be incorporated within the shaft of a laparoscopic surgical instrument. Additionally, the laparoscopic surgical instrument may comprise a beam splitting unit disposed at the distal end of the fiber optical assembly, such that the illumination can be directed onto at least part of an element of a biliary tree held in the surgical instrument from an orientation other than frontal. That beam splitting unit thus may deliver at least part of such illumination as back-lit illumination. Another example implementation can involve any of the above described systems, wherein the imaging system has reduced sensitivity outside of the wavelength region of between 600 and 700 nanometers, thereby generating the spectral range where the sensitivity of the optical system is not reduced. This above described imaging system may comprise a broadband detector array and a filter having a passband in the wavelength region of between 600 and 700 nanometers. Such a system may further comprise a fiber optical assembly for conveying illumination returned from the region to the imaging system. In that case, the fiber optical assembly may be integral to a laparoscopic surgical instrument, and if so it may be incorporated within the shaft of the laparoscopic surgical instrument.

In all of the above described systems, the spectrally reduced sensitivity of the optical system outside of the spectral range should enable improved identification of the bile tree.

Other exemplary implementations of such systems may further comprise an illuminating source emitting in the near infra-red region where hemoglobin has an increased absorbance, such that blood vessels can be more readily detected.

Additionally, in any such systems, the illuminating source may be an autonomous source, which can be positioned in the abdominal cavity to provide illumination, or it may be a strip source, so that the source can be positioned on the distal side of a body part being imaged.

Finally, any of the above described systems may incorporate an endoscopic illumination source adapted to be inserted through the patient's mouth and stomach.

Yet other implementations perform a method of identifying elements of a biliary tree of a subject in the performance of laparoscopic cholecystectomy, the method comprising imaging a region in which the biliary tree is situated, by projecting illumination onto the region from a light source, and generating images of the illuminated region,

wherein the imaging is performed with spectrally increased sensitivity in a spectral region where the optical absorption of the contents of the bile tree is substantially higher than that of surrounding tissues.

In such a method, the spectrally increased sensitivity may be generated by projecting the illumination primarily in the wavelength region of between 600 and 700 nanometers. Such illumination may be produced using a filter having a passband in the wavelength region of between 600 and 700 nanometers with a broadband source. Alternatively, the illuminating source may comprise a LED or a laser diode having emittance in the wavelength region of between 600 and 700 nanometers.

Any of the above described methods may further comprise projecting the illumination onto the region by means of a fiber optical assembly. Such a fiber optical assembly may be integral to a laparoscopic surgical instrument, in which case the fiber optical assembly may be incorporated within the shaft of a laparoscopic surgical instrument. Additionally, the laparoscopic surgical instrument may comprise a beam splitting unit disposed at the distal end of the fiber optical assembly, such that the illumination can be directed onto at least part of an element of a biliary tree held in the surgical instrument from an orientation other than frontal. That beam splitting unit thus may deliver at least part of such illumination as back-lit illumination.

Another exemplary implementation can involve any of the above described methods, wherein the spectrally increased sensitivity is achieved by generating the images of the illuminated region in the wavelength region of between 600 and 700 nanometers. This can be achieved by using a filter having a passband in the wavelength region of between 600 and 700 nanometers with a broadband detector array.

Such methods may further comprise conveying illumination returned from the surgical region to the imaging system by means of a fiber optical assembly. Such a fiber optical assembly may be integrated into a laparoscopic surgical instrument, and if so, it may be incorporated within the shaft of a laparoscopic surgical instrument.

According to yet further implementations of the methods of this disclosure, the illumination may also projected in a broadband region other than between 600 and 700 nanometers, such that illumination can be switched from broadband to 600-700 nm. In such a situation, an image of the bile duct area imaged in the 600-700 nm range can be displayed overlaid on a broadband optical image.

Finally, in any of the above described methods, the illumination may be conveyed endoscospically to the patient's duodenum.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

Fig. l illustrates schematically the organs of the upper abdomen and upper gastrointestinal system, showing the positions of the components of the bile system to be operated on using the system of the present application;

Fig. 2 illustrates schematically an enlarged region of the anatomy shown in Fig. 1, showing the vessels running through the triangle of Calot;

Fig. 3 is a graphic plot of the spectral absorbance of bile, blood and fat over the visible and near infra-red regions of the spectrum;

Fig. 4 is a schematic rendering of one exemplary implementation of the apparatus for performing the novel laparoscopic cholecystectomy method of the present disclosure;

Fig. 5 is a schematic rendering of an alternative exemplary implementation of the apparatus of Fig. 4;

Fig. 6 illustrates schematically an exemplary surgical clip applicator, incorporating a built-in illumination source, for use in the systems shown in Figs. 4 or 5;

Fig. 7 is a schematic representation of the working end of a surgical clip applier of the jaw and shaft type, incorporating its own fiber optical illumination assembly for use in the various systems of this application; and

Fig. 8 is a schematic representation of the working end of a modified grasper or clip applier of the jaw and shaft type, with an integral fiber optical illuminator system;

Fig. 9 shows a surgical tool of the type shown in Fig. 8, incorporating an optical beam splitter and bender accessory for enabling illumination both to the sides of the tissue or vessel being held in the grasper jaws, and through the tissue or vessel itself, providing back-light illumination;

Fig. 10 shows an independent light source in the form of a LED strip emitting within the range of 600-700 nm;

Fig. 11 shows an independent light source that includes an attachment mechanism to anchor it to tissues in the cavity; and

Fig. 12 shows schematically an endoscopic implementation of the systems of this disclosure. DETAILED DESCRIPTION

Reference is now made to Fig. 1, which illustrates schematically the organs of the upper abdomen and upper gastro-intestinal system, showing the positions of the components of the bile system relative to its associated organs, starting with the stomach 100 leading into the duodenum 101. The gallbladder 103 situated inferior to the right lobe of the liver 102, stores and transfers bile through the biliary cystic duct 104, which lead into the common bile duct 105 and from there into the duodenum 101. Bile from the liver 102 flows through the right hepatic duct 106 and the left hepatic duct 107 into the common hepatic duct 108 and from there through the common bile duct 105 into the duodenum through the sphincter of Oddi 109, through which the pancreatic secretions also flow into the duodenum. In the LC procedure, the gall bladder 103 and its biliary cystic duct 104 must be excised without harming the closely disposed common hepatic duct 108 and common bile duct 105.

However, in addition to the crowded environment of the biliary tree, which must not be injured inadvertently, there are also blood vessels passing through the region, as shown in Fig. 2, which illustrates schematically an enlarged region of the anatomy shown in Fig. 1. Fig. 2 further illustrates the complexity of the operation region of the LC procedure. In Fig. 2, there is shown the inferior surface of the liver 102 with the common hepatic duct 108 and the cystic duct 104 and their junction at the top end of the common bile duct 105. In addition to these biliary tree ducts, a number of arteries cross through this region, including the cystic artery 201 and the right hepatic artery 202, as supplied by the aorta 203. The region marked with the dashed lines is that known as Calot's triangle 204, and it is vital that no injury be sustained during the LC procedure, by the cystic artery 201 and the right hepatic artery 202, both of which run through Calot's triangle. In the LC procedure, surgical graspers are used to hold and manipulate the bile ducts or other vessels or organs which it is necessary to manipulate, and surgical pliers, clampers and cutters are used in order to perform the dissecting and excising of the desired organs or vessels. The surgical procedure of the present application thus being essentially identical to prior art LC procedures, the difference being in the manner in which the relevant bile ducts are differentiated from other vessels and tissues within the patient,

Reference is now made to Fig. 3, which is a graphic plot of the spectral absorbance in arbitrary units of bile, blood and fat over the visible and near infra-red regions of the spectrum. As is observed, blood is essentially transparent from about 610 nm into the NIR, which is the reason for the red color of blood. On the other hand, bile shows an absorption region approximately between the wavelengths 600 to 700 nm. (Bile also has an absorption minimum in the region of 550 nm., which is the reason why bile has a greenish color.) Therefore, by viewing the light transmitted through the region of the operation in the approximately 600-700 nm range, since the bile-bearing vessels absorb these wavelengths substantially more than blood or fat does, they appear much darker in the camera images than the surrounding tissues, appearing even black if the optical passage through the bile is long enough, and can thus be more readily and clearly identified from the surrounding tissues and vessels, than would be possible if white light were to be used for this viewing process.

Reference is now made to Fig. 4 which is a schematic rendering of one exemplary implementation of the apparatus for performing the novel laparoscopic cholecystectomy method of the present disclosure. Fig. 4 shows four laparoscopic incisions executed in the patient's upper abdomen, with trocars inserted in each. The first port 40 is used for insertion of a laparoscopic camera 41, which can be a standard CMOS or CCD visible light laparoscopic camera. The camera may have its conventional broadband light source integrated therein for frontal illumination of the surgical site, so that comparisons can be made between the conventionally viewed laparoscopic images, and those generated using the novel illumination schemes of the present disclosure. A second port 42 is used to insert a surgical grasper 43, used to manipulate organs or tissues at the operation site. In the exemplary implementation of Fig. 4, the grasper 43 in this port is shown with a fiber optic light source 44, for illuminating the operation site within the abdomen, with light of the required wavelength - in the preferred band around 650nm. The detailed construction of such an instrument is shown in the examples illustrated in Figs. 6 to 8 hereinbelow. The light can either be generated by a wavelength specific source, or can be provided from a broadband source with a band pass filter, all located outside the body. Since the grasper jaws are able to access the posterior side of the vessel or organ which they are grasping, the instrument can be constructed so that the illumination is emitted from the rear of the vessel or organ, relative to the camera, so that backlit illumination transmitted through the vessel or organ can be imaged by the camera 41. This backlit illumination method is therefore advantageous over the previously mentioned illumination provided through the camera port A third port 45 is shown having another grasper 46 inserted into its trocar, and a fourth port 47 may have a clamping or clipping instrument 48 for completing the operation once the relevant bile duct has been identified and separated.

Reference is now made to Fig. 5 which is a schematic rendering of an alternative exemplary implementation of the apparatus for performing a laparoscopic cholecystectomy procedure according to the methods of the present disclosure. The surgical instruments used are essentially the same, as those of the implementation of Fig. 4, and are so numbered, but this method differs from that shown in Fig. 4 in that the wavelength discrimination to limit the image data to wavelengths in the preferred band between approximately 600 and 700 nm is performed at the imaging module, and not at the illuminating module. Thus, broadband illumination can be applied through a conventional laparoscopic illuminator, which could be camera integrated, or at a separate port, and the detected light from the operation scene is filtered at the camera 41 to image only the desired wavelength range within the approximately 600 to 700 nm region. The band pass filter (not shown separately in Fig. 5) can be computer controlled and can be added on the camera itself 41, or on the optical fiber extending from the camera itself into the abdominal cavity. A switch may be used to switch between filtered light and broadband light, in order to compare the standard broadband view with the absorbance enhanced view in the 600- 700 nm band.

Reference is now made to Fig. 6, which illustrates schematically an example surgical clip applicator 60, similar in optical operation to that shown as item 43 in the system of Fig. 4 above, according to another implementation of the devices of the present disclosure. The device differs from conventional surgical clippers or cutters in that it incorporates the light source required to implement the methods of this application. In the clip applicator 60 of Fig. 6, the source 61 is built into the handle of the device, and it may conveniently be a LED source emitting at the desired wavelength around the 650 nm region. As the surgical region also contains blood vessels, according to a further implementation, the source can also be constructed to provide emission in the Near Infra-Red (NIR) region of the spectrum, in a region where there is preferential absorption by oxygenated hemoglobin in the blood. Then, blood vessels in the region can be more readily viewed, and even further distinguished from the bile vessels. A switchable illumination between the broadband visible, and the red light (600-700 nm), and the selected NIR region thus provides the surgeon with the optimum tools for differentiating the various organs and vessels in the surgical region of interest. In these implementations, the sensitivity of the imaging system must be adapted to be sensitive also in the spectral range of the selected NIR region.

Furthermore, the imaging system can be adapted to provide a composite image of the bile tree system obtained using the 600 to 700nm red illumination overlaid on a broadband optical image displayed on the system monitor. In this manner, the surgeon is able to relate the spectrally selected bile tree image to the conventional white light image to which he/she is accustomed.

An optical fiber 62 conveys the illuminating light from the source 61 down the shaft assembly 63 into the patient's abdomen. The clipper can have a squeezable trigger assembly 64, to enable the surgeon to perform the duct clipping at the right moment that the duct is correctly positioned using the grasper(s), and this handle may have a built in switch 65, to enable the selected spectral illumination to be applied or to switch between broadband illumination and the selected wavelength illumination and NIR illumination, if supplied. The illumination switch may alternatively be positioned 66 on the body of the clipper, or at any location which the surgeon' s finger can readily access.

Reference is now made to Fig. 7, which is a schematic representation of the distal (working) end of a surgical clip applier of the jaw and shaft type 70, similar to that shown in Fig. 6, except that the illumination is conveyed to the operation site through an optical fiber assembly 71 attached to the main shaft 72, and which may be detachable or integral. The light emitting end of the fiber 73 is visible near the stowed working tool 74 of the instrument.

Reference is now made to Fig. 8, which is a schematic representation of the working end of a modified grasper or clip applier 80, of the jaw and shaft type, with an integral fiber optical illuminator system. The fiber optic assembly may be installed on the main shaft and may be detachable or integral, as previously described. The light emitting end 81 of the optical fiber can be seen when the jaws 82 are in the open position. On either side of the main emission port 81, there is seen two additional fiber ports, and their function is now described with reference to Fig. 9.

Fig. 9 shows how the surgical tool 80 of the type shown in Fig. 8, incorporates an optical beam splitter accessory 91 for enabling the grasper to illumination through and to the sides of the grasped tissue providing back-light illumination. Fig. 9 shows a disassembled view of the optical illumination end of the instrument, with the optical fiber or a thin tube carrying the optical fiber extended 92 out of the grasper. The beam splitter head directs part of the illuminating beam to the two side ports. When the jaws 82 grasp an organ or a vessel, part of the grasped vessel or organ overflows out of the jaws, and can then be illuminated by light from the side ports which pass through the organ or vessel in a back-lit configuration. Such a back-lit transmission image is the most effective method of increasing the image contrast of the bile carrying features which the system is intended to identify.

However, this configuration is unable to perform back-lit imaging of organs or vessels which are not being grasped or excised, because of the cramped space within the surgical region of interest. Reference is now made to Fig. 10, which shows an independent light source in the form of a light-emitting strip 100 which can provide illumination in the range of 600-700 nm. In the example shown, the illumination strip can take the form of a thin LED strip with its associated LED devices and associated power supply elements, encased in transparent or semi-transparent material. Because of its thin dimensions, it can be maneuvered behind or inserted between tissues to provide regular or back-lit illumination, depending on its position.

Reference is now made to Fig. 11, which shows another independent light source in the form of a single LED device 110 encapsulated within a plastic housing 111. It can be inserted through a trocar and includes an attachment mechanism, such as a number of hooks 112 to anchor it to tissues in the abdominal cavity.

The above described systems and methods use incisions in the patient's abdomen to access the bile system organs. Reference is now made to Fig. 12 which illustrates an endoscopic device 120 for use in a procedure that needs to identify the bile duct. Use of such an endoscopic device enables at least one incision in the patient to be replaced by an endoscopic insertion. This procedure is similar to the endoscopic retrograde cholangio pancreatography (ERCP) procedure, where the clinicians face the same problem of identity as in LC. In ERCP procedures, an endoscope 120 is inserted through the mouth, down the esophagus, into the stomach, through the pylorus and into the duodenum, where entrance to the bile ducts can be accomplished. For conventional ERCP, broadband light is used for this this procedure. According to the present described implementation, if an illumination source having the selected spectral range described in the previous embodiments - 600 to 700 nm - is used as the illumination source emitted from the end 121 of the endoscope, it becomes possible to more readily detect bile bearing organs and vessels from the end of the endoscope, thereby saving at least one incision for the illumination source.

It is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.

Claims

CLAIMS We claim:

1. A laparoscopic system for identifying elements of a biliary tree of a subject in the performance of laparoscopic cholecystectomy, said system comprising:

an optical system adapted to provides images of a surgical region in which said biliary tree is situated, said optical system comprising:

an illuminating source projecting illumination onto said region; and an imaging system adapted to generate images of said illuminated region,

wherein said optical system has reduced sensitivity outside of a spectral range where the optical absorption of the contents of said bile tree is substantially higher than that of surrounding tissues.

2. A system according to claim 1, wherein said illuminating source has an emittance primarily in the wavelength region of between 600 and 700 nanometers, thereby generating said spectral range where said sensitivity of said optical system is not reduced.

3. A system according to claim 2, wherein said illuminating source comprises a broadband source and a filter having a passband in the wavelength region of between 600 and 700 nanometers.

4. A system according to claim 2, wherein said illuminating source comprises a LED or a laser diode having emittance in the wavelength region of between 600 and 700 nanometers.

5. A system according to any of the previous claims further comprising a fiber optical assembly for conveying said illumination onto said region.

6. A system according to claim 5, wherein said fiber optical assembly is integral to a laparoscopic surgical instrument.

7. A system according to claim 6, wherein said fiber optical assembly is incorporated within the shaft of a laparoscopic surgical instrument.

8. A system according to either of claims 6 and 7, wherein said laparoscopic surgical instrument comprises a beam splitting unit disposed at the distal end of said fiber optical assembly, such that said illumination can be directed onto at least part of an element of a biliary tree held in said surgical instrument from an orientation other than frontal.

9. A system according to claim 8, wherein said beam splitting unit delivers at least part of such illumination as back-lit illumination.

10. A system according to claim 1, wherein said imaging system has reduced sensitivity outside of the wavelength region of between 600 and 700 nanometers, thereby generating said spectral range where said sensitivity of said optical system is not reduced.

11. A system according to claim 10 wherein said imaging system comprises a broadband detector array and a filter having a passband in the wavelength region of between 600 and 700 nanometers.

12. A system according to either of claims 11 and 12 further comprising a fiber optical assembly for conveying illumination returned from said surgical region to said imaging system.

13. A system according to claim 12, wherein said fiber optical assembly is integral to a laparoscopic surgical instrument.

14. A system according to claim 12, wherein said fiber optical assembly is incorporated within the shaft of a laparoscopic surgical instrument.

15. A system according to any of the previous claims wherein said spectrally reduced sensitivity of said optical system outside of said spectral range enables improved identification of said bile tree.

16. A system according to any of the previous claims, further comprising an illuminating source emitting in the near infra-red region where hemoglobin has an increased absorbance, such that blood vessels can be more readily detected.

17. A system according to any of the previous claims, wherein said illuminating source is an autonomous source, which can be positioned in the abdominal cavity to provide illumination.

18. A system according to any of the previous claims, wherein said illuminating source is a strip source, such that said source can be positioned on the distal side of a body part being imaged.

19. A system according to any of the previous claims, wherein said illuminating source is an endoscopic illumination source adapted to be inserted through the patient's mouth and stomach.

20. A method of identifying elements of a biliary tree of a subject in the performance of laparoscopic cholecystectomy, said method comprising:

imaging a region in which said biliary tree is situated, by projecting illumination onto said region from a light source, and generating images of said illuminated region,

wherein said imaging is performed with spectrally increased sensitivity in a spectral region where the optical absorption of the contents of said bile tree is substantially higher than that of surrounding blood-containing tissues.

21. A method according to claim 20, wherein said spectrally increased sensitivity is generated by projecting said illumination primarily in the wavelength region of between 600 and 700 nanometers.

22. A method according to claim 21, wherein said illumination is produced using a filter having a passband in the wavelength region of between 600 and 700 nanometers with a broadband source.

23. A method according to claim 21, wherein said illuminating source comprises a LED or a laser diode having emittance in the wavelength region of between 600 and 700 nanometers.

24. A method according to any of claims 20 to 23, wherein said illumination is projected onto said region by means of a fiber optical assembly.

25. A method according to claim 24, wherein said fiber optical assembly is integral to a laparoscopic surgical instrument.

26. A method according to claim 25, wherein said fiber optical assembly is incorporated within the shaft of a laparoscopic surgical instrument.

27. A method according to any of claims 24 to 26, wherein said illumination is projected onto at least part of said region by using a beam splitting unit disposed at the distal end of said fiber optical assembly, such that said illumination can be directed onto at least part of an element of a biliary tree held in said surgical instrument from an orientation other than frontal..

28. A method according to claim 27, wherein said beam splitting unit delivers at least part of such illumination as back-lit illumination.

29. A method according to claim 20, wherein said spectrally increased sensitivity is achieved by generating said images of said illuminated region in the wavelength region of between 600 and 700 nanometers.

30. A method according to claim 29 wherein said images are generated by using a filter having a passband in the wavelength region of between 600 and 700 nanometers with a broadband detector array.

31. A method according to either of claims 29 and 30, comprising the further step of conveying illumination returned from said surgical region to said imaging system by means of a fiber optical assembly.

32. A method according to claim 31, wherein said fiber optical assembly is integrated into a laparoscopic surgical instrument.

33. A method according to claim 31, wherein said fiber optical assembly is incorporated within the shaft of a laparoscopic surgical instrument.

34. A method according to claim 21, wherein said illumination is also projected in a broadband region other than between 600 and 700 nanometers, such that illumination can be switched from broadband to 600-700 nm.

35. A method according to claim 34, wherein an image of the bile duct area imaged in the 600-700 nm range can be displayed overlaid on a broadband optical image.

36. A method according to any of claims 20 to 35, wherein said illumination is conveyed endoscospically to the patient's duodenum.