Impact of non-muscle cutting periumbilical transverse incision on the risk of incisional hernia as compared to midline incision during laparoscopic colon cancer surgery: a study protocol for a multi-centre randomised controlled trial

Background: Minimally invasive surgery has become popular as a surgical approach for colorectal cancer because it has fewer complications related to the abdominal incision and perioperative complications. However, the incidence of incisional hernias in laparoscopic surgery has been reported to be similar to that in open surgery. We developed a new method, the non-muscle-cutting periumbilical transverse incision, for a small incision in laparoscopic colon cancer surgery. This study aims to evaluate the effectiveness of the non-muscle-cutting periumbilical transverse incision in comparison with the midline incision in reducing the incidence of an incisional hernia in patients undergoing laparoscopic colon cancer surgery. Methods: This is an open-label, multi-centre, parallel, superiority, and randomised trial. Altogether, 174 patients will be allocated in a 1:1 ratio to either the midline incision or the non-muscle-cutting periumbilical transverse incision group, after stratifying by the location of the tumour (right- or left-sided). The primary outcome of this study is the incidence of incisional hernias (both symptomatic and radiologic hernias) at 12 months after surgery. The secondary outcomes include operative outcomes, 30-day postoperative complications, pathological results, and patient-reported outcomes (short form-12 health survey questionnaire and body image questionnaire). Both primary (intention-to-treat) and secondary (as-treated principles) analyses will be performed for all outcomes. The statistical significance level was set at p < 0.05 (two-sided testing). Discussion: This trial may show that the non-muscle-cutting periumbilical transverse incision will reduce the incidence of incisional hernias compared to the midline incision. Trial registration: Clinical Research Information Service (CRiS) of Republic of Korea, KCT0006082. Registered on April 12, 2021.