In abdominal and vascular surgery anastomosis, the joining together of hollow structures, is an important goal. The ability to establish continuity between two hollow structures can relieve blockage due to cancer, inflammation or other pathology, can allow the removal of abnormal tissue or organs, and, by bypassing a blocked segment, can allow the unimpeded movement of food or facilitate the flow of blood or bile through the body.
Anastomoses are most commonly formed at open abdominal surgery (laparotomy). Hand sewn anastomoses, usually in two or even three layers, are widely performed but are time consuming and require large incisions for hand access. Stapled anastomoses became widely performed especially in colonic surgery since they allowed surgeons to remove low rectal tumours. The short rectal remnant could be joined to the colon above the tumour at a site where it was difficult to place stitches by hand, and in consequence allowed patients to recover without needing a permanent colostomy. The advent of laparoscopic surgery staplers allowed anastomoses to be formed through incisions of 1-2 cm or so that were just large enough to allow passage of these instruments inside the abdominal or thoracic cavity.
Some aids to form anastomoses have been developed. J. B. Murphy, an American surgeon working in Chicago in the 1880's, popularized surgical anastomoses by creating a compression button device for anastomosis. The device had two mushroom-shaped buttons, which could be placed in the two organs to be joined. The buttons could be pressed together by an internal spring in the stalk of the mushroom and the organs would be welded together by the consequent ischaemia (lack of blood supply) at the sites where the buttons were pressed together. Eventually the button device would fall through into the gut, leaving an anastomosis or hole and be passed through the body into the toilet. Compression button anastomoses are still used at open colonic surgery. The use of magnets to compress tissue to form an anastomosis has also been described, and a spring compression button method using a biofragmentable ring has been employed, especially in the rectum.
An anastomosis procedure has been described in an article entitled “Anastomosis at Flexible Endoscopy: an experimental study of compression button gastrojejunoscopy”, P Swain and N Mills, Gastrointestinal Endoscopy 1991, 37: 625-631, in which, as its title implies, a method is described of forming anastomoses using a flexible endoscope. The method described there involved introducing a flexible endoscope into one of the two structures to be joined (in this case the stomach), and entering the second of the two structures (in this case the small bowel) by forming an incision in the abdomen of the subject. The present invention is directed, in one aspect thereof, to the formation of anastomoses without the need to make such external incisions, though in other aspects thereof the means described herein which make this possible are applied to anastomoses in the formation of which such incisions are made.
The ability to form anastomoses using flexible endoscopic or percutaneous procedures without opening the abdomen or chest or using laparoscopic methods might offer advantages especially to patients with advanced cancer or in elderly or sick patients, who might withstand conventional surgery poorly. In particular, flexible endoscopy might allow anastomoses to be formed from stomach to small bowel, duodenum to gallbladder, and small bowel to colon.
Flexible endoscopy allows access to many hollow organs including oesophagus, stomach, duodenum, small intestine and colon, and most flexible endoscopes have a channel through which instruments can be passed. Although the flexible endoscopes employed for most conventional purposes do not provide information on the location of tubular structures outside the organ, modified flexible endoscopes employing ultrasound are available which do. Endoscopic ultrasound is a hybrid method, which uses ultrasound imaging at the tip of the endoscope but retains the optical imaging and internal instrument channel of a conventional endoscope. Some such endoscopes have their imaging array constructed in a linear fashion, which allows good ultrasound visualization of organs adjacent to the organ in which the tip of the endoscope lies.