The incidence of extraction site incisional hernia after minimally invasive colorectal surgery: a systematic review and meta-analysis

Aim: Minimally invasive colorectal surgery reduces surgical trauma with better preservation of abdominal wall integrity, but the extraction site is still at risk of incisional hernia (IH). The aim of this study was to determine pooled incidence of IH for each type of extraction site and to compare rates of IH after midline, nonmidline and Pfannenstiel extraction. Method: A systematic review and meta-analysis was conducted using the PRISMA guidelines. Single-armed and multiple-armed cohort studies and randomized controlled trials regarding minimally invasive colorectal surgery were searched from five databases. Outcomes were pooled and compared with random-effects, inverse-variance models. Risk of bias within the studies was assessed using the Cochrane ROBINS-I and RoB 2 tool. Results: Thirty six studies were included, with a total 11,788 patients. The pooled extraction site IH rate was 16.0% for midline (n = 4081), 9.3% for umbilical (n = 2425), 5.2% for transverse (n = 3213), 9.4% for paramedian (n = 134) and 2.1% for Pfannenstiel (n = 1449). Nonmidline extraction (transverse and paramedian) showed significantly lower odds ratios (ORs) for IH when compared with midline extraction (including umbilical). Pfannenstiel extraction resulted in a significantly lower OR for IH compared with midline [OR 0.12 (0.50–0.30)], transverse [OR 0.25 (0.13–0.50)] and umbilical (OR 0.072 [0.033–0.16]) extraction sites. The risks of surgical site infection, seroma/haematoma or wound dehiscence were not significantly different in any of the analyses. Conclusion: Pfannenstiel extraction is the preferred method in minimally invasive colorectal surgery. In cases where Pfannenstiel extraction is not possible, surgeons should avoid specimen extraction in the midline.