Authors' reply: Closure of abdominal midline incisions: STITCH trial

We thank our colleagues for their comments on our study. Tetsuji Fujita suggests that there is no evidence that continuous suture techniques are better than interrupted sutures. Although results from one trial did not show a difference between continuous and interrupted sutures for midline incisions, strong evidence suggests that a continuous suture technique with a longlasting material is the best method to close a midline incision and prevent hernia formation. The continuous technique is therefore quicker and more cost effective.

Both techniques were standardised in our study. The length of the wounds and the length of stitches and suture remnants were measured in every patient to calculate the ratio of suture length to wound length. To prevent bias in our study, randomisation was stratified by centre and department. Our study was based on the study of Millbourn and colleagues, in which only patients with a suture length to wound length ratio of 4:1 or higher were investigated. The suggestion that our sample size was based on a study with inadequate suture length to wound length ratios is not correct.

We agree with Ketan Gajjar and Mahmood Shafi that there was a difference in suture size between the groups. This issue is fully acknowledged in our discussion. We compared the most commonly used suture technique with the small bites technique of Israelsson. Whereas the suture material was comparable, the size of suture and needle differed. Alternatives to the large bites technique using small size sutures, or the small bites technique using large sutures, might not be safe. Further research might be needed to establish whether small bites or thinner needles and suture materials reduce incisional hernias in the small bites group.

Clean and contaminated cases and gynecology cases were randomly divided into both groups and were analysed separately in the subgroup analysis. No subgroup effects were identified in logistic regression analysis to adjust for these cofactors or other predisposing risk factors.

Results from our follow-up of clinical and radiological examination showed a 23% incidence of incisional hernia in the control group at 1 year follow-up. Because diagnosis of incisional hernia was done by radiological examination, small, asymptomatic incisional hernias are thought to have been diagnosed, which might not have been detected by physical examination. The incidence rate of incisional hernia at 1 year follow-up in our study is comparable to that of randomised clinical trials with up to 3 years of follow-up using ultrasound for the diagnosis of incisional hernia.