Breaking strength of small intestinal anastomoses.

The breaking strength of standardized small bowel anastomoses at different times after surgery was studied in the rat. The anastomotic strength with sutures in place successively decreased during the first 3 postoperative days to approximately 15 percent of the immediate postoperative value. This indicates a rapid decrease in the suture holding capacity of the gut wall in the early postoperative course. From the fourth day onward a rapid increase in strength was recorded. This could be due not only to deposition of collagen in the tissue bridging the anastomosis but also to the regained capacity of the gut wall to withstand tearing forces. After 14 days the strength of the anastomosis was due mainly to healing, and the relative contribution from the sutures was negligible. It may be that tearing of sutures through the tissue is more important than defective healing for anastomotic complications.