The experimental basis of intestinal suturing

Factors that incite inflammation at the healing wound prolong the lag period of wound healing and delay the return of strength at the suture line. Inflammation activates bowel-wall collagenase, which degrades the collagen within the wound, eroding the foundation in which sutures are anchored. Experimental studies have compared the impact of various surgical techniques. Sutures placed by hand uniformly invoke an inflammatory response because dragging the thread through the bowel wall injures tissue. Single-layer anastomoses heal more rapidly than double-layer suture lines. The inner layer causes avascular necrosis of the inverted cuff. Experimental studies have not clearly shown the superiority of inverting suture lines over everting ones. Experimental studies done over the last century indicate that the single-layer inverting anastomosis recommended by Lembert and Halstead adequately compensates for enteric wound weakness during the lag period. Other techniques of sewing an anastomosis provide no clear advantage. Other factors that incite inflammation also delay enteric wound healing. Debris, necrotic tissue, or infection illicit an inflammatory response with detrimental effects on the anastomosis. Antibiotics, by assisting in the control of infection or by minimizing the size of an inoculum help speed healing. Stapling devices violate many of the doctrines of intestinal suturing. Experimental studies suggest, however, that staple lines incite a minimal inflammatory response. Consequently, wounds closed with stapling devices regain strength more rapidly than those closed with traditional surgical techniques.