Endoluminal compression clip: full-thickness resection of the mesenteric bowel wall in a porcine model.

BACKGROUND: Performing a full-thickness intestinal wall resection of a sessile polyp located on the mesenteric side with a compression clip may lead to compression of mesenteric vessels. The application of such a clip may therefore cause a compromised blood supply in the particular bowel segment, leading to perforation. OBJECTIVE: To evaluate the performance of a newly developed, nitinol compression clip, called the NiTi clamp, for full-thickness resection of the bowel wall, while the clip is deliberately deployed endoluminally on the mesenteric side. DESIGN: Prospective animal study. Multinational, multidisciplinary; gastroenterology and general surgery, research cooperation. SETTING: Animal research laboratory. INTERVENTION: Six pigs were operated upon and endoscopically evaluated and then killed after 3 weeks. Linear compression closure clips based on nitinol springs were used. Three longitudinal enterotomies were performed: in the cecum, spiral colon, and proximal rectum. Four clips were deployed in each animal. MAIN OUTCOME MEASUREMENTS: A total of 23 clips were deployed. The average expulsion day was 9 days. RESULTS: All but 3 clips were normally expelled. One pig developed bowel ischemia due to intussusception. In endoscopic procedures, no signs of significant segmental mucosal ischemia were found. The macroscopic appearance of the compression closure lines was thin and delicate, but epithelialization was significantly delayed at 5 sites. LIMITATION: Differences between porcine and human colorectal anatomy. CONCLUSION: Full-thickness clamping of the bowel with the NiTi clamp, including the local mesenteric vasculature, does not significantly impair local healing of the clamp site and gives hope to further development of novel full-thickness endoscopic resection technologies.

Foreign-body granulomas within intramyocardial arteries in a transcoronary safety assessment in pigs.

Foreign-body granulomas within intramyocardial arteries were detected in three domestic pigs (Sus scrofa domestica) in a routine transcoronary safety assessment study. The foreign bodies stained light grayish-blue by hematoxylin and eosin (H&E) and were strongly birefringent by polarized light microscopy. By their morphological features, they were identified as cotton fibers. Embolization of foreign-body material into the myocardial arteries following catheter-based procedures is an unusual event, and its occurrence may lead to granulomatous foreign-body reaction and misinterpretation of histological results.

End-to-end compression anastomosis of the rectum: a pig model.

BACKGROUND: Generations of investigators have attempted to achieve compression bowel anastomosis by a sutureless device, providing temporary support to the tissue and facilitating the natural healing process. The biocompatibility of nickel-titanium alloy has made it attractive for use in medical implants and devices, and several studies have described the creation of a side-to-side compression anastomosis in colon surgery with a nickel-titanium clip. We evaluated the feasibility and safety of a newly designed gun for applying a nickel-titanium compression anastomosis ring (CAR) to create an end-to-end colorectal anastomosis in a porcine model. MATERIALS AND METHODS: A segment of the proximal rectum was resected in 25 pigs. The bowel ends were anastomosed transanally by an end-to-end CAR device. The animals' follow-up continued for up to 8 weeks, and included general health status, weight gain, blood tests, and abdominal X-ray. They were then sacrificed. The anastomoses were studied for burst pressure, anastomotic index, and histopathology. RESULTS: One pig died due to iatrogenic bowel injury unrelated to the CAR device. There was no other morbidity/mortality. The other animals recovered and gained weight. Burst pressure studies demonstrated a minimum pressure of 160 mmHg at time point 0 that escalated quickly to >300 mmHg. The mean anastomotic index after 8 weeks was 0.81. Histologic evaluation revealed minimal inflammation and minimal fibrosis at the anastomosis site. CONCLUSION: The principles of compression anastomosis are better executed with the use of memory shape alloys. The promising results of this novel technique should encourage further studies of this technology.