Failures after abdominal wound closure (early dehiscences and late incisional hernias) are due to breakage of sutures, slippage of knots or tearing out of sutures from the tissues. The suture-holding capacity of the entire thickness of muscle and aponeurosis is nearly twice that of the anterior rectus sheath, and deep bites (1-0 cm from the cut edges) are nearly twice as secure as bites of 0-5 cm. In a random controlled clinical trial of 357 major laparotomies, closure with either layered monofilament nylon or mass polyglycolic acid or steel resulted in 2 burst abdomens (0-56%), 10 incisional hernias due to suture failure (3-4%) and 8 incisional hernias caused by deep sepsis (2-7%). There were no statistically significant differences among the treatment groups, but 1 patient in the nylon and 3 in the steel groups had persistent sinuses until their sutures were removed.