Healing of Ileocolic Nitinol Compression Anastomosis: A Novel Porcine Model of Subtotal Colectomy

Background: There are limited large animal models for the research of novel anastomotic technologies. Subtotal colectomy requires the anastomosis of relatively remote segments of the alimentary tract that are different anatomically, histologically, and pose significant physiological challenge. The quest for a foreign material-free anastomotic line reintroduced nitinol compression anastomosis into clinical use in the last decade. Objective: To evaluate the safety, histological, and physiological parameters of side-to-side ileocolic nitinol compression anastomosis in a newly developed large animal model, mimicking the human subtotal colectomy. Intervention: Resection of the entire spiral colon with an ileocolic side-to-side compression anastomosis in 12 animals, compared to resection of a short ileal segment in 6 animals. All anastomoses were constructed by using a novel nitinol-based compression device. The animals were followed up to 30 days postoperatively and were reoperated and sacrificed. Results: All 12 animals underwent successful subtotal colectomy with side-to-side nitinol compression anastomosis. No signs of abdominal infection were found. The increase in the colectomized animals' bodyweight over the postoperative course was significantly lower and the animals presented with longer periods of diarrhea. The histopathology revealed minimal inflammation and foreign body reaction with good alignment of the bowel wall layers in both groups. The anastomotic line width was shown to be reduced during the healing course of the compression anastomoses. Conclusions: Side-to-side nitinol compression anastomosis is safe and demonstrates favorable functional and histopathological features. The porcine model of subtotal colectomy can be used for further research of novel anastomotic technologies.