Effect of suture technique on early healing of intestinal anastomoses in rats

To see if the site and tension of sutures had any influence on early breaking strength in intestinal anastomoses.

161 Male Wistar rats.

First experiment: after laparotomy and division of the ileum an inverted end to end anastomosis was made in a single layer with 14 interrupted sutures of 7/0 polypropylene. All sutures were inserted 3 mm from the cut edges. The rats were randomly allocated to one of four groups according to the size of the loop of suture used: tight (n = 38), 0.4 mm (n = 22), 0.9 mm (n = 35), or 2.0 mm (n = 24). Second experiment: the method used was the same except that sutures were placed 1.5 mm from the cut edges and the rats were randomly allocated to one of two groups according to the size of loop of suture--tight (n = 20), or 0.9 mm (n = 22).

Breaking strength measured in a tensiometer (both experiments); and myeloperoxidase activity/g tissue, hydroxyproline content and solubility/biopsy specimen (first experiment only).

Breaking strength decreased proportionally the tighter the sutures were tied, and the differences were significantly greater when the sutures were placed closer to the cut edges. Anastomotic myeloperoxidase activity, hydroxyproline content, and soluble: total hydroxyproline ratio were similar in all groups.

Tight sutures may promote proteolytic tissue degradation by reducing the local availability of circulating proteinase inhibitors.