Influence of suture technique on laparotomy wound healing: an experimentalstudy in the rat

A suture length to to wound length ratio (SLWL ratio) of 4:1 for laparotomy closure has proven in clinical studies to reduce incisional hernia inciden ce. The effect of different SLWL ratios on the mechanical qualities of the healing incision has not been examined experimentally. In 50 rats, the musc ulo-fascial lever of median laparotomies was closed with polypropylene sutu res using SLWL ratios of 8:1. 4:1. 2:1 and 17:1. Single and running sutures . different tissue bites and different suture tensions wen applied. Five ra ts served as controls. After 14 days. the horizontal strength of the incisi on was tested in a digitised tensiometer. The SLWL ratio, suture tension an d suture technique proved to have significant influences on the mechanical strength of the incision. Running sutures and especially closures with a ra tio of between 4: I and 8. 1 proved significantly stronger than wounds clos ed with single sutures. When small tissue bites were applied, the positive influence of running sutures was equalised in the early phase of wound heal ing. High suture tension led to significantly weaker scars independent of t he applied suture technique. In accordance with clinical data, it could be proven experimentally that running closure of midline laparotomies with a S LWL ratio above 4:1 avoiding high suture tension exerts a significantly pos itive effect on the mechanical strength of the incision. Further studies ar e needed to allow measurement and better control of suture tension.