The Future of Endoscopic Technology
The Future of Endoscopic Technology
New Orleans, Wednesday, May 19, 2004 -- The plenary session of the American Society for Gastrointestinal Endoscopy (ASGE) featured reports on new and emerging endoscopic technologies and provided a glimpse into the future. Two of the key areas of focus were: (1) new technologies that may allow advanced endoscopic surgeries either within or outside of the lumen of the gastrointestinal tract, and (2) advances in the instrumentation for performing colonoscopy.
This report explores both of these topical issues, as discussed during this key session at Digestive Disease Week (DDW) 2004, and frames their relevance in the appropriate clinical context.
Background and Context
One of the main limitations of current endoscopic technique is the barrier of remaining within the gastrointestinal lumen. The currently available equipment is excellent for probing and viewing the lumen of the upper and lower gastrointestinal tract, however, it cannot provide diagnostic information or therapeutic applications for structures outside of the gastrointestinal tract. The first endoscopic technology capable of providing diagnostic information beyond the lumen of the gastrointestinal tract was endoscopic ultrasound. This technology merges the focused access into the gastrointestinal tract that endoscopy provides, along with imaging information obtained from a high-frequency ultrasound transducer. The indications for (and the impact of) endoscopic ultrasound are now widely appreciated. The availability of linear-array ultrasonography with fine-needle aspiration has firmly established endoscopic ultrasonography as part of our endoscopic armamentarium. This ability to accurately image and sample the gastrointestinal tract outside of the gastrointestinal lumen stimulated great interest regarding the further diagnostic -- and especially therapeutic -- extragastrointestinal applications of endoscopic technology.
The concept of placing an endoscope into the gastrointestinal tract and creating access through the gastrointestinal wall to allow for visualization, diagnosis, and therapeutic intervention is relatively simple in concept but very difficult in practice. Some of the challenges that exist are: the creation of a transmural access point with sufficient diameter to allow endoscopes and endoscopic instruments to advance; maintaining sterility of the peritoneal cavity despite per-oral instruments and the bacteria that colonize the gastrointestinal tract; creation of pneumoperitoneum to distend the peritoneal cavity to permit adequate visualization; the availability of endoscopes and endoscopic equipment to perform therapeutic procedures; and at completion of the procedure, to close the transmural access point in a secure manner. Despite all of these barriers, there is intense interest in achieving these goals because the end result would be the ability to perform abdominal surgery without an abdominal incision, thus potentially reducing complications associated with traditional and laparoscopic surgery.
These concepts are not futuristic and are feasible in the practice of gastrointestinal endoscopy; this technique already exists in humans in the setting of pancreatic necrosis. At DDW 2003, in fact, it was reported that pancreatic necrosectomy was performed endoscopically in patients with a history of pancreatitis and pancreatic necrosis. In a procedure similar to standard endoscopic cyst-gastrostomy, the endoscope was placed into the retroperitoneal cavity, and under direct visualization using available endoscopic equipment such as directed lavage and basket devices, endoscopic necrosectomy was successfully performed. Several of the studies presented during this year's ASGE plenary session expand on this concept and report on emerging technologies.
Endoscopic Transgastric Ligation
The "Apollo Group" is a group of investigators whose goal is to develop new endoscopic technologies to successfully perform extragastrointestinal endoscopic surgeries. Investigators comprising the Apollo Group include Sydney Chung, Peter Cotton, Christopher Gostout, Robert Hawes, Anthony Kalloo, Sergey Kantsevoy, and Pankaj Pasricha, among others.
During this year's DDW meeting, Sergey Kantsevoy and coinvestigators presented a study reporting the successful performance of per-oral transgastric ligation of fallopian tubes with long-term survival in a porcine model. These investigators used 5 female 50-kg pigs whose stomachs were first irrigated with an antibiotic solution. Transluminal gastric access was achieved by puncture with a needle knife followed by TTS (through-the-scope) balloon dilation of the track to 20 mm. The investigators then advanced standard endoscopes that had undergone high-level disinfection and gas sterilization into the peritoneal cavity through a sterilized overtube. In the pig model, the fallopian tubes are relatively easy to identify and 1 tube in each pig was ligated using an endoloop device (the other fallopian tube was not instrumented and served as a control). The patency of the tubes was assessed by hysterosalpingograms before and after ligature, and pigs were survived for 2-3 weeks.
The tubal ligation was successful in all animals and no complications were observed. There was no evidence of peritonitis or intra-abdominal adhesions on necropsy. This well-designed and -executed study serves as a proof of concept that transgastric abdominal surgery can be safely performed. However, the application of tubal ligation was chosen for its technical ease and it is unlikely that this endoscopic treatment will be used in humans.
Transgastric Biliary Surgery
Per-Ola Park, Maria Bergstrom, and Paul Swain, presented the results of their experimental studies in transgastric biliary surgery. The studies were performed in 13 30-kg pigs (including 5 survival pigs) and involved the placement of 2 endoscopes into the stomach (the second was placed over a guidewire). Two separate transgastric incisions were made using a needle knife, followed by guidewire placement and incision extension using a sphincterotome until the opening was of sufficient diameter to allow transgastric placement of the endoscope. In this way, the placement of 2 transgastric endoscopes (which simulates the techniques of the laparoscopic surgeons with pneumoperitoneum) is achieved and each endoscope can be independently manipulated and used to view the other instrument.
The investigators viewed the gallbladder and then dissected the base of the gallbladder bed using a needle knife. The cystic duct could be identified, clipped, and transected to allow for gallbladder removal. The study authors also were able to pull the gallbladder into a gastric incision and tack it to the gastric wall using clips and then perform an incision into the gallbladder to allow for a cholecystogastrostomy.
Swain and colleagues continue to push the boundaries and limitations of endoscopy and challenge us with the possibilities of this technology. This impressive demonstration shows the feasibility of performing procedures that would be directly beneficial to patients. However, there were limitations noted in this study, including the fact that it was difficult to assess the force generated by the instruments and that there was limited exposure of the instruments -- clearly there is a need for better instrumentation.
Endoscopic Robot System
Another ASGE plenary presentation directly addressed the limitations of the current equipment and the need to develop new endoscopic technologies to facilitate transgastric endoscopic surgery. Richard Rothstein and colleagues reported on the development of a computer-assisted robot system for advanced therapeutic procedures. They developed a robotic system to telerobotically control interchangeable instruments attached (but not through) the endoscope. Robotic instruments allow multiarticulating arms to manipulate tissue in various directions. Under computer control, the physician manages a console with a pair of handles mounted on movable arms that allows the operator to directly control the movement and activities of the endoscopic equipment. A variety of surgical tools were devised including tissue graspers, scissors, needle drivers, and a needle knife. The concept of robotically-controlled endoscopic surgery is similar to already existing robotic laparoscopic surgical technology, such as the da Vinci and Zeus systems. These investigators were able to perform a telerobotically controlled endoscopic gastric mucosal resection (EMR) using a porcine stomach in an ex vivo model. They were then able to perform a gastric EMR in a live anesthetized pig without complications. This computer-based robotic technology and new instrumentation may allow for endoscopically directed advanced endoscopic procedures.
Endoscopic Suturing
Bing Hu and colleagues reported on endoscopic suturing without extracorporeal knots and a prototype device called the Eagle Claw V. This device uses a curved needle that is placed under direct endoscopic view, and this places a suture with a relatively deep "bite" that allows for intracorporeal knotting. One of the difficulties with the currently available endoscopic suturing techniques is that after the sutures have been placed, the suturing instruments must be removed from the gastrointestinal tract and a knot tying/suture cutting device must be passed from outside the body to the site of the suture. Clearly, less cumbersome techniques are needed if endoscopic suturing is to be applied to broader applications.
These investigators used a prototype device called the Eagle Claw V, which can place sutures and knot the suture (using a "tail" device, and the sutures are then cut using standard endoscopic scissors) to ligate the splenic artery (mean diameter, 3 mm) of pigs employing a perfused Erlangen endoscopic training model (simulation for diagnostic and interventional endoscopy). The depth of the placed sutures was consistently within the muscularis propria layer and occasionally penetrated to the serosa (other endoscopic devices rarely penetrate the muscular layer). However, there were some device failures and other problems in this preliminary experience.
The development of a complete endoscopic suturing system that is effective and safe would greatly facilitate new applications of endoscopic suturing, such as in the control of gastrointestinal bleeding, and would represent a substantial contribution to the field of extragastrointestinal surgery.
Advances in Colonoscopy
Another major topic area addressed during the ASGE plenary session at this year's DDW meeting was new technology offering potential improvements in the ability to perform colonoscopy. Colonoscopy has become the major endoscopic procedure performed in gastrointestinal endoscopy given the increasing awareness of the importance of colorectal cancer screening. Although the instrumentation to perform colorectal cancer screening has improved in recent years, both in the mechanical characteristics of the instruments as well as in the optics, there is clearly the need for additional improvements to facilitate the passage of the instrument to the cecum and to diminish the discomfort felt by patients during exam.
Shike and colleagues presented the results of a study with a novel instrument, the ColonoSight, a pull-powered assisted, disposable, and non-fiber-optic colonoscope. This device uses air-pressure assisted pull technology to pull the colonoscope rather than the traditional technique of pushing the instrument for advancement. In order to achieve this goal, the system uses a pneumatic mechanism that generates a forward force (0.5 kg compared with maximal forces used during standard colonoscopy examinations of up to 4.4 kg) just below the tip of the scope that decreases the need to push the instrument. As the instrument advances, a protective disposable sheath is advanced. This facilitates instrument advancement and decreases user work because only manipulation of the handles is needed to navigate. This instrument also uses a disposable sheath that contains the working channels (3.7 mm diameter), which eliminates the need for disinfection between applications. The light source is also new, using an integrated LED (light-emitting diode) light source in the tip that eliminates the need for a light transmitted through the scope from a box at the base of the scope. These investigators evaluated the prototype in pigs and sheep and then described a clinical trial. Screening (and volunteer) colonoscopies were performed using this device in 72 patients, with a success rate of reaching the cecum in 88% of cases; mean time to reach the cecum was 12.3 minutes (including 9 patients in whom the cecum was reached in less than 5 minutes). They were able to perform therapeutic interventions, including biopsy, polypectomy, and argon plasma coagulation, without difficulty. The sheath barrier was an effective protection against infection. This study demonstrates some of the possibilities for improvements in the current colonoscopic equipment and highlights the potential of a pull instrument. However, the instrument's cecal intubation rate and time to reach cecum do not represent improvements over our currently available instruments, although this may be due to patient selection (some with previously failed colonoscopies) as well as to the physician learning curve involved with using the device.
Paul Swain and colleagues reported on a device called the "cath-cam," which represents another new concept in colonoscopic technology. This guidewire/catheter device uses advances in CCD (charge-coupled device) technology that reduce the pixel size such that the image-capturing device is much smaller. These investigators developed a light, flexible catheter that could carry an ultraslim, flexible video endoscope of 3 mm in diameter with a pixel number equivalent to conventional endoscopes. This catheter was disposable and much lighter than the traditional endoscope, but could develop torque and featured a light-emitting diode, increased tip flexibility, an accessory channel, lens irrigation and air insufflation, as well as a hydrophilic coating (a new concept). The catheter tip was attached to the miniature camera. Bench tests showed that looped guidewires could be passed through the accessory channel and the wire-guided catheters exerted significantly average (reduced force about 40% overall compared with standard colonoscopy) and less peak force on the wall of the colon than a standard colonoscope. In addition, the distal tip bend stiffness was 5 times less than that of a standard colonoscope. The investigators then performed studies in 11 live pigs (whose colons are approximately twice as long as humans) and showed that the lumen could be held in view and the cath-cam could be advanced as far as the colonoscope (and usually further). It was reported that the looped guidewire was used in 2 patients to help advance a conventional colonoscope, although no specific data were presented; a larger human study is planned. Thus, looped guidewires have the potential to allow advancement through long distances of tortuous colons and assist endoscopists in performing colonoscopies.
Concluding Remarks
It is hoped that this discussion of these key presentations provides a view toward the future of endoscopy. Major advances in endoscopic technology have occurred over the past 30 years -- advances that have transformed the field from one of purely diagnostic applications to one including therapeutic applications. Technologic innovations will facilitate advances in our ability to perform minimally invasive endoscopic surgery, optimize patient comfort during procedures, and ultimately lead to improved outcomes in patients with gastrointestinal disorders.
References
New Orleans, Wednesday, May 19, 2004 -- The plenary session of the American Society for Gastrointestinal Endoscopy (ASGE) featured reports on new and emerging endoscopic technologies and provided a glimpse into the future. Two of the key areas of focus were: (1) new technologies that may allow advanced endoscopic surgeries either within or outside of the lumen of the gastrointestinal tract, and (2) advances in the instrumentation for performing colonoscopy.
This report explores both of these topical issues, as discussed during this key session at Digestive Disease Week (DDW) 2004, and frames their relevance in the appropriate clinical context.
Background and Context
One of the main limitations of current endoscopic technique is the barrier of remaining within the gastrointestinal lumen. The currently available equipment is excellent for probing and viewing the lumen of the upper and lower gastrointestinal tract, however, it cannot provide diagnostic information or therapeutic applications for structures outside of the gastrointestinal tract. The first endoscopic technology capable of providing diagnostic information beyond the lumen of the gastrointestinal tract was endoscopic ultrasound. This technology merges the focused access into the gastrointestinal tract that endoscopy provides, along with imaging information obtained from a high-frequency ultrasound transducer. The indications for (and the impact of) endoscopic ultrasound are now widely appreciated. The availability of linear-array ultrasonography with fine-needle aspiration has firmly established endoscopic ultrasonography as part of our endoscopic armamentarium. This ability to accurately image and sample the gastrointestinal tract outside of the gastrointestinal lumen stimulated great interest regarding the further diagnostic -- and especially therapeutic -- extragastrointestinal applications of endoscopic technology.
The concept of placing an endoscope into the gastrointestinal tract and creating access through the gastrointestinal wall to allow for visualization, diagnosis, and therapeutic intervention is relatively simple in concept but very difficult in practice. Some of the challenges that exist are: the creation of a transmural access point with sufficient diameter to allow endoscopes and endoscopic instruments to advance; maintaining sterility of the peritoneal cavity despite per-oral instruments and the bacteria that colonize the gastrointestinal tract; creation of pneumoperitoneum to distend the peritoneal cavity to permit adequate visualization; the availability of endoscopes and endoscopic equipment to perform therapeutic procedures; and at completion of the procedure, to close the transmural access point in a secure manner. Despite all of these barriers, there is intense interest in achieving these goals because the end result would be the ability to perform abdominal surgery without an abdominal incision, thus potentially reducing complications associated with traditional and laparoscopic surgery.
These concepts are not futuristic and are feasible in the practice of gastrointestinal endoscopy; this technique already exists in humans in the setting of pancreatic necrosis. At DDW 2003, in fact, it was reported that pancreatic necrosectomy was performed endoscopically in patients with a history of pancreatitis and pancreatic necrosis. In a procedure similar to standard endoscopic cyst-gastrostomy, the endoscope was placed into the retroperitoneal cavity, and under direct visualization using available endoscopic equipment such as directed lavage and basket devices, endoscopic necrosectomy was successfully performed. Several of the studies presented during this year's ASGE plenary session expand on this concept and report on emerging technologies.
Endoscopic Transgastric Ligation
The "Apollo Group" is a group of investigators whose goal is to develop new endoscopic technologies to successfully perform extragastrointestinal endoscopic surgeries. Investigators comprising the Apollo Group include Sydney Chung, Peter Cotton, Christopher Gostout, Robert Hawes, Anthony Kalloo, Sergey Kantsevoy, and Pankaj Pasricha, among others.
During this year's DDW meeting, Sergey Kantsevoy and coinvestigators presented a study reporting the successful performance of per-oral transgastric ligation of fallopian tubes with long-term survival in a porcine model. These investigators used 5 female 50-kg pigs whose stomachs were first irrigated with an antibiotic solution. Transluminal gastric access was achieved by puncture with a needle knife followed by TTS (through-the-scope) balloon dilation of the track to 20 mm. The investigators then advanced standard endoscopes that had undergone high-level disinfection and gas sterilization into the peritoneal cavity through a sterilized overtube. In the pig model, the fallopian tubes are relatively easy to identify and 1 tube in each pig was ligated using an endoloop device (the other fallopian tube was not instrumented and served as a control). The patency of the tubes was assessed by hysterosalpingograms before and after ligature, and pigs were survived for 2-3 weeks.
The tubal ligation was successful in all animals and no complications were observed. There was no evidence of peritonitis or intra-abdominal adhesions on necropsy. This well-designed and -executed study serves as a proof of concept that transgastric abdominal surgery can be safely performed. However, the application of tubal ligation was chosen for its technical ease and it is unlikely that this endoscopic treatment will be used in humans.
Transgastric Biliary Surgery
Per-Ola Park, Maria Bergstrom, and Paul Swain, presented the results of their experimental studies in transgastric biliary surgery. The studies were performed in 13 30-kg pigs (including 5 survival pigs) and involved the placement of 2 endoscopes into the stomach (the second was placed over a guidewire). Two separate transgastric incisions were made using a needle knife, followed by guidewire placement and incision extension using a sphincterotome until the opening was of sufficient diameter to allow transgastric placement of the endoscope. In this way, the placement of 2 transgastric endoscopes (which simulates the techniques of the laparoscopic surgeons with pneumoperitoneum) is achieved and each endoscope can be independently manipulated and used to view the other instrument.
The investigators viewed the gallbladder and then dissected the base of the gallbladder bed using a needle knife. The cystic duct could be identified, clipped, and transected to allow for gallbladder removal. The study authors also were able to pull the gallbladder into a gastric incision and tack it to the gastric wall using clips and then perform an incision into the gallbladder to allow for a cholecystogastrostomy.
Swain and colleagues continue to push the boundaries and limitations of endoscopy and challenge us with the possibilities of this technology. This impressive demonstration shows the feasibility of performing procedures that would be directly beneficial to patients. However, there were limitations noted in this study, including the fact that it was difficult to assess the force generated by the instruments and that there was limited exposure of the instruments -- clearly there is a need for better instrumentation.
Endoscopic Robot System
Another ASGE plenary presentation directly addressed the limitations of the current equipment and the need to develop new endoscopic technologies to facilitate transgastric endoscopic surgery. Richard Rothstein and colleagues reported on the development of a computer-assisted robot system for advanced therapeutic procedures. They developed a robotic system to telerobotically control interchangeable instruments attached (but not through) the endoscope. Robotic instruments allow multiarticulating arms to manipulate tissue in various directions. Under computer control, the physician manages a console with a pair of handles mounted on movable arms that allows the operator to directly control the movement and activities of the endoscopic equipment. A variety of surgical tools were devised including tissue graspers, scissors, needle drivers, and a needle knife. The concept of robotically-controlled endoscopic surgery is similar to already existing robotic laparoscopic surgical technology, such as the da Vinci and Zeus systems. These investigators were able to perform a telerobotically controlled endoscopic gastric mucosal resection (EMR) using a porcine stomach in an ex vivo model. They were then able to perform a gastric EMR in a live anesthetized pig without complications. This computer-based robotic technology and new instrumentation may allow for endoscopically directed advanced endoscopic procedures.
Endoscopic Suturing
Bing Hu and colleagues reported on endoscopic suturing without extracorporeal knots and a prototype device called the Eagle Claw V. This device uses a curved needle that is placed under direct endoscopic view, and this places a suture with a relatively deep "bite" that allows for intracorporeal knotting. One of the difficulties with the currently available endoscopic suturing techniques is that after the sutures have been placed, the suturing instruments must be removed from the gastrointestinal tract and a knot tying/suture cutting device must be passed from outside the body to the site of the suture. Clearly, less cumbersome techniques are needed if endoscopic suturing is to be applied to broader applications.
These investigators used a prototype device called the Eagle Claw V, which can place sutures and knot the suture (using a "tail" device, and the sutures are then cut using standard endoscopic scissors) to ligate the splenic artery (mean diameter, 3 mm) of pigs employing a perfused Erlangen endoscopic training model (simulation for diagnostic and interventional endoscopy). The depth of the placed sutures was consistently within the muscularis propria layer and occasionally penetrated to the serosa (other endoscopic devices rarely penetrate the muscular layer). However, there were some device failures and other problems in this preliminary experience.
The development of a complete endoscopic suturing system that is effective and safe would greatly facilitate new applications of endoscopic suturing, such as in the control of gastrointestinal bleeding, and would represent a substantial contribution to the field of extragastrointestinal surgery.
Advances in Colonoscopy
Another major topic area addressed during the ASGE plenary session at this year's DDW meeting was new technology offering potential improvements in the ability to perform colonoscopy. Colonoscopy has become the major endoscopic procedure performed in gastrointestinal endoscopy given the increasing awareness of the importance of colorectal cancer screening. Although the instrumentation to perform colorectal cancer screening has improved in recent years, both in the mechanical characteristics of the instruments as well as in the optics, there is clearly the need for additional improvements to facilitate the passage of the instrument to the cecum and to diminish the discomfort felt by patients during exam.
Shike and colleagues presented the results of a study with a novel instrument, the ColonoSight, a pull-powered assisted, disposable, and non-fiber-optic colonoscope. This device uses air-pressure assisted pull technology to pull the colonoscope rather than the traditional technique of pushing the instrument for advancement. In order to achieve this goal, the system uses a pneumatic mechanism that generates a forward force (0.5 kg compared with maximal forces used during standard colonoscopy examinations of up to 4.4 kg) just below the tip of the scope that decreases the need to push the instrument. As the instrument advances, a protective disposable sheath is advanced. This facilitates instrument advancement and decreases user work because only manipulation of the handles is needed to navigate. This instrument also uses a disposable sheath that contains the working channels (3.7 mm diameter), which eliminates the need for disinfection between applications. The light source is also new, using an integrated LED (light-emitting diode) light source in the tip that eliminates the need for a light transmitted through the scope from a box at the base of the scope. These investigators evaluated the prototype in pigs and sheep and then described a clinical trial. Screening (and volunteer) colonoscopies were performed using this device in 72 patients, with a success rate of reaching the cecum in 88% of cases; mean time to reach the cecum was 12.3 minutes (including 9 patients in whom the cecum was reached in less than 5 minutes). They were able to perform therapeutic interventions, including biopsy, polypectomy, and argon plasma coagulation, without difficulty. The sheath barrier was an effective protection against infection. This study demonstrates some of the possibilities for improvements in the current colonoscopic equipment and highlights the potential of a pull instrument. However, the instrument's cecal intubation rate and time to reach cecum do not represent improvements over our currently available instruments, although this may be due to patient selection (some with previously failed colonoscopies) as well as to the physician learning curve involved with using the device.
Paul Swain and colleagues reported on a device called the "cath-cam," which represents another new concept in colonoscopic technology. This guidewire/catheter device uses advances in CCD (charge-coupled device) technology that reduce the pixel size such that the image-capturing device is much smaller. These investigators developed a light, flexible catheter that could carry an ultraslim, flexible video endoscope of 3 mm in diameter with a pixel number equivalent to conventional endoscopes. This catheter was disposable and much lighter than the traditional endoscope, but could develop torque and featured a light-emitting diode, increased tip flexibility, an accessory channel, lens irrigation and air insufflation, as well as a hydrophilic coating (a new concept). The catheter tip was attached to the miniature camera. Bench tests showed that looped guidewires could be passed through the accessory channel and the wire-guided catheters exerted significantly average (reduced force about 40% overall compared with standard colonoscopy) and less peak force on the wall of the colon than a standard colonoscope. In addition, the distal tip bend stiffness was 5 times less than that of a standard colonoscope. The investigators then performed studies in 11 live pigs (whose colons are approximately twice as long as humans) and showed that the lumen could be held in view and the cath-cam could be advanced as far as the colonoscope (and usually further). It was reported that the looped guidewire was used in 2 patients to help advance a conventional colonoscope, although no specific data were presented; a larger human study is planned. Thus, looped guidewires have the potential to allow advancement through long distances of tortuous colons and assist endoscopists in performing colonoscopies.
Concluding Remarks
It is hoped that this discussion of these key presentations provides a view toward the future of endoscopy. Major advances in endoscopic technology have occurred over the past 30 years -- advances that have transformed the field from one of purely diagnostic applications to one including therapeutic applications. Technologic innovations will facilitate advances in our ability to perform minimally invasive endoscopic surgery, optimize patient comfort during procedures, and ultimately lead to improved outcomes in patients with gastrointestinal disorders.
References
Kantsevoy S, Jagannath S, Vaugh CA, et al. Per-oral transgastric endoscopic ligation of fallopian tubes with long-term survival in a porcine model. Gastrointest Endoscp. 2004;59:AB112.
Park P-E, Bergstrom M, Swain P. Experimental studies in transgastric biliary surgery. Gastrointest Endosc. 2004;59:AB113.
Rothstein R, Ailinger R, Peine W. Computer-assisted robot system for advanced therapeutic procedures. Gastrointest Endosc. 2004;59:AB113.
Bing Hu, et al. Endoscopic suturing without extracorporeal knots: The Eagle Claw V. Gastrointest Endoscop. 2004;59:AB114.
Shike M, Repici A, Cohen LB, Goldfarb-Albak S, Fireman Z. Major advances in colonoscopic technology: The ColonoSight(R) a pull-powered assisted disposable, non fiber-optic colonoscope. Gastrointest Endosc. 2004;59:AB113.
Swain P, Fritscher-Ravens A, Long G, Fox G. The Cath-Cam. A new concept in colonoscopy. Gastrointest Endosc. 2004;59:AB114.
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