Optimized force range of magnetic compression anastomosis in dog intestinal tissue

Background: Magnetic compression anastomosis (MCA) is a commonly used anastomosis method. MCA was widely used in tissues repair, gastroenterostomy, choledochoenterostomy, and so on. It is safer and more effective than stapler and manual surgical suturing. However, there are few detailed studies on the biomechanical characteristics and tissue transformation mechanisms of the anastomosis process. In this research, taking intestinal tissue as research object, we need to determine an optimal compressive force range to provide a biomechanical reference for the design of anastomats. Methods: Magnets with different magnetic force groups (2.06, 321, 6.27, 13.3 and 192 N) were implanted into each dog to form intestinal tissue side-to-side anastomoses. Five dogs were euthanized on each of postoperative day 1, day 3, and day 7. Anastomoses were then harvested and compared with respect to postoperative complications, histology and tear-resistance load capacity (TRLC). Results: The TRLC of anastomotic tissue formed by magnets with different magnetic forces differed markedly, but with the tissue growth, the TRLC differences between groups were decreased. Histology of anastomotic tissue showed that, in the initial stage, the anastomoses compressed by 2.06-N magnets did not form effectively, while the leakage appeared in the anastomoses compressed by 19.2-N magnets, in the rest groups, with magnetic force increasing, severity of ischemia and necrosis of compressed tissue increased and healing speed of anastomotic tissue improved. In the late stage, the influence of magnetic force for anastomotic tissue was gradually diminished. Conclusions: The magnetic force applied on the magnetic compression anastomats affects the necrosis speed of compressed tissue and the healing speed of anastomotic tissue. The optimal compressive force range for intestinal compression anastomosis is 627 N to 13.3 N, and the actual optimal compression pressure is 79.8 kPa - 169 kPa. (C) 2019 Elsevier Inc. All rights reserved.