Risk factors for wound complications in midline abdominal incisions related to the size of stitches

Midline abdominal incisions should be closed continuously with a suture length (SL) to wound length (WL) ratio above 4 using small stitches. The effect on the rate of wound complications of a very high ratio and other potential risk factors when closure is performed with small stitches is unknown.

Patients operated on through a midline incision were randomised to closure with small stitches, placed 5-8 mm from the wound edge and less than 5 mm apart, or with large stitches, placed more than 1 cm from the wound edge. Patient and operative variables were registered. Surgical site infection and incisional hernia were recorded.

Three hundred and twenty-one patients were randomised to closure with small stitches and 370 with large stitches. Infection and herniation were less common with small stitches. With small stitches, no risk factors for infection or herniation were identified. With large stitches, wound contamination and the patient being diabetic were independent risk factors for infection, and long operation time and surgical site infection were risk factors for herniation. A very high SL to WL ratio did not affect the complication rates.

In midline abdominal incisions closed with small stitches, no risk factors for surgical site infection or incisional hernia were identified. Increasing the ratio very much above 4 had no adverse effects on the rate of wound complications. The higher rates of infection and herniation with an SL to WL ratio over 5 and in overweight patients in previous reports were probably related to wounds being closed with large stitches.