Development of a new access device for transgastric surgery

Abstract

Flexible endoscope-based endoluminal and transgastric surgery for cholecystectomy, appendectomy, bariatric, and antireflux procedures show promise as a less invasive form of surgery. Current endoscopes and instruments are inadequate to perform such complex surgeries for a variety of reasons: they are too flexible and are insufficient to provide robust grasping and anatomic retraction. The lack of support for a retroflexed endoscope in the peritoneal cavity makes it hard to reach remote structures and makes vigorous retraction of tissues and organs difficult. There is also a need for multiple channels in scopes to allow use of several instruments and to provide traction/countertraction. Finally, secure means of tissue approximation are critical. The aim was to develop and test a new articulating flexible endoscopic system for endoluminal and transgastric endosurgery. A multidisciplinary group of gastrointestinal physicians and surgeons worked with medical device engineers to develop new devices and instruments. Needs assessments and design parameters were developed by consensus. Prototype devices were tested using inanimate models until usable devices were arrived at. The devices were tested in nonsurvival pigs and dogs. The devices were accessed through an incision in the wall of the stomach and manipulated in the peritoneal cavity to accomplish four different tasks: right upper quadrant wedge liver biopsy, right lower quadrant cecal retraction, left lower quadrant running small bowel, and left lower quadrant exposure of esophageal hiatus. In another three pigs, transgastric cholecystectomy was attempted. The positions of the device, camera, and endosurgical instruments, with and without ShapeLock technology, were recorded using laparoscopy and endoscopy and procedure times and success rates were measured. Instrument design parameters and their engineering solutions are described. Flexible multilumen guides which could be locked in position, including a prototype which allowed triangulation, were constructed. Features of the 18-mm devices include multidirectional mid body and/or tip angulation, two 5.5-mm accessory channels allowing the use of large (5-mm) flexible endosurgical instruments, as well as a 4-mm channel for an ultraslim prototype video endoscope (Pentax 4 mm). Using the resulting devices, the four designated transgastric procedures were performed in anesthetized animals. One hundred percent of the transgastric endosurgical procedures were accomplished with the exception of a 50% success for hiatal exposure, a 90% success rate for wedge liver biopsy, and a 33.3% success rate for cholecystectomy. A new endosurgical multilumen device and advanced instrumentation allowed effective transgastric exploration and procedures in the abdominal cavity including retraction of the liver and stomach to allow exposure of the gallbladder, retraction of the cecum, manipulation of the small bowel, and exposure of the esophageal hiatus. This technology may serve as the needed platform for transgastric cholecystectomy, gastric reduction, fundoplication, hiatus hernia repair, or other advanced endosurgical procedures.