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.