Implantable endoscopic gastric bypass - device and experimental procedure.

Malabsorptive bariatric surgery is an effective treatment option for morbid obesity, but may be associated with complications and side effects. We have developed a new experimental approach to creating a gastric bypass through an intraluminal access. The goal is to reduce postoperative complications and to reduce mid-term side-effects of malabsorptive bypass food passage and to allow easy reversion of the procedure. The new procedure is based on an implantable gastric bypass device, installed by combined transoral flexible and minimally invasive abdominal access. The newly developed device and procedure were studied in a pilot experimental trial in the porcine animal model (n=8). Endpoints were the feasibility of the technical procedure, the ability of the animal to eat and digest food, the implant functionality over the survival period and the absence of major complications over a short-term follow-up (one week). The procedure was technically successful in all eight animals. Animals were able to take in food and water till sacrifice. Four animals had major complications (one abdominal wall dehiscence, one invagination ileus of the small bowel, one dehiscence of the gastro-jejunal anastomosis and one myocardial infarction) and did not complete follow-up. In two cases migration of the device into the stomach was observed. The difference between our experimental technique and the gold standard surgical methods for gastric bypass consists of the endoluminal approach by implanting an intraluminal gastric bypass device. This concept avoids gastric transsection and an additional anastomosis and enables an adjustable food passage between the bypass and the natural duodenal passage. Further long-term follow-up studies are required.

[Experimental study on a new method for colonoscopic closure of large-bowel perforations with the OTSC clip]. / Experimentelle Untersuchung zu einem neuen Verfahren für den koloskopischen Verschluss von Dickdarmperforationen mit dem OTSC-clip.

Iatrogenic perforation of the colon during interventional endoscopic procedures, e.g., mucosectomy, is a problematic complication, as safe treatment often requires surgical repair. Iatrogenic perforation of the colon is indeed a rare complication; however, given the increasing case numbers in interventional endoscopy it is of considerable practical relevance. The closure of perforations can be achieved with conventional endoscopic clips; however, these working channel based clips are often too small to close a perforation securely. Therefore, we have developed a novel endoscopic clipping system that can be attached to the tip of the endoscope. This over-the-scope-clip system (OTSC), made of Nitinol, was tested in an experimental trial (domestic pig, 50-60 kg) for its applicability for perforation closure. In acute experiments, tight endoscopic closure of 10 perforations in five animals was demonstrated; perforations were made through repeat biopsy. In three further animals, the postoperative course was studied over a period of 2 weeks. Peritonitis was not found in any of these animals. The local healing result at the site of implantation was good. Clips were present 2 weeks after the procedure. In this experimental study, the OTSC clip system was found to be a simple and secure method of iatrogenic colon perforation closure.

Development of a transoral fundoplication device and related experimental research.

This paper describes a device and surgical techniques developed between 1999 and 2003 to enable an entirely transoral approach to fundoplication. The Endofundoplication System (EFS) system consisted of a multifunctional flexible tube for oral introduction (18 mm) as the key component, with a specially designed retroverted grasper that was used to grasp the lower esophageal sphincter (LES) area of the esophagus, for invaginating the LES into the stomach and folding the gastric wall onto the wall of the intraabdominal esophagus. The EFS system was finally studied in a consecutive series of animal experiments in the domestic pig (n = 10). In nine out of the ten cases the procedure could be successfully completed and the animals survived six weeks according to the study protocol. The clinical follow-up of the nine animals went without problems. The animals behaved normally the first day after the procedure and tolerated regular diet very well. No signs of pain or any abdominal pathology were found in the clinical follow-up. Follow-up by endoscopy and fluoroscopy showed a subsequent postoperative migration of fasteners within the tissue. After autopsy and macroscopic inspection of the gastroesophageal junction (GEJ), we found firm tissue indurations around the fasteners. This may indicate that the fastener as a foreign body leads to a sufficient amount of scar tissue formation to contribute to permanent fixation of the tissue layers. The basic advantage of the EFS technique was seen by our group in the fact that it comes closer to the shape and function of a classical fundoplication than any other techniques proposed at the time we did our development. The nipple valve created by the EFS technique is, however, geometrically not identical to any existing fundoplication technique and is not directly comparable to any such procedure.