An evidence map and synthesis review with meta-analysis on the risk of incisional hernia in colorectal surgery with standard closure

Purpose To assess the incidence of incisional hernia (IH) across various type of incisions in colorectal surgery (CS) creating a map of evidence to define research trends, gaps and areas of future interest. Methods Systematic review of PubMed and Scopus from 2010 onwards. Studies included both open (OS) and laparoscopic (LS). The primary outcome was incidence of IH 12 months after index procedure, secondary outcomes were the study features and their influence on reported proportion of IH. Random effects models were used to calculate pooled proportions. Meta-regression models were performed to explore heterogeneity. Results Ninetyone studies were included reporting 6473 IH. The pooled proportions of IH for OS were 0.35 (95% CI 0.27-0.44) I-2 0% in midline laparotomies and 0.02 (95% CI 0.00-0.07), I-2 52% for off-midline. In case of LS the pooled proportion of IH for midline extraction sites were 0.10 (95% CI 0.07-0.16), I-2 58% and 0.04 (95% CI 0.03-0.06), I-2 86% in case of off-midline. In Port-site IH was 0.02 (95% CI 0.01-0.04), I-2 82%, and for single incision surgery (SILS) of 0.06-95% CI 0.02-0.15, I-2 81%. In case of stoma reversal sites was 0.20 (95% CI 0.16-0.24). Conclusion Midline laparotomies and stoma reversal sites are at high risk for IH and should be considered in research of preventive strategies of closure. After laparoscopic approach IH happens mainly by extraction sites incisions specially midline and also represent an important area of analysis.