Mechanisms and prevention of decrease in wound margin strength in intestinal anastomoses and laparotomy wounds

From the present investigation it can be summarized that breaking strength of an incisional wound, measured with the sutures in situ, decreased markedly early after the operation in all tissues investigated if the sutures were inserted 1.5 mm from the incision; that the decrease was also found if new sutures, placed between and substituting the old, were inserted before measuring breaking strength, indicating that the decrease in strength occurs all along the wound; that breaking strength did not decrease if the sutures were inserted 3 mm from the incision; that breaking strength decreased markedly in the wounds sutured under stretching, even if the sutures were inserted 4 mm from the incision; that collagen content and solubility, and the histological appearance of the submucosal collagen layer, were only insignificantly changed in the early period after the operation; that the decrease in breaking strength was eliminated in animals made neutropenic by anti-neutrophil serum; that the decrease in breaking strength was reduced, but not eliminated, by oxygen free radical scavengers; that the decrease in breaking strength was eliminated by a group-specific serine proteinase inhibitor and was reduced, but not eliminated, by proposed collagenase inhibitors; that the serine proteinase inhibitor and the oxygen free radical scavengers did not reduce the increase in myeoloperoxidase activity in the anastomotic segment and did not, at histological examination, reduce the accumulation of neutrophils there, and that the serine proteinase inhibitor did not impair the subsequent gain in breaking strength, measured after removal of the sutures, during the fibroplasia period. From these findings it can be concluded that there is a narrow zone of decrease in tissue strength adjacent to an incisional wound; that measurement of collagen content and solubility, and histology, are methods too crude to reveal the collagen changes that should be responsible for the decrease; that the neutrophils seem to be responsible for the decrease; that the mechanisms are probably a combined effect of neutral proteinases and oxygen free radicals, and that drug therapy modifying neutrophil function may be of value as prophylaxis against intestinal anastomotic dehiscence and burst abdomen.