Onlay Versus Sublay Mesh Repair for Incisional Hernias: A Systematic Review

Incisional hernias are a common problem following major abdominal surgery. There are numerous surgical techniques described in the existing English scientific literature with different planes for mesh placement. The current review aims to compare onlay versus sublay repair in managing incisional hernias. A systematic literature search was conducted on Embase, the Cochrane Library, PubMed, and Medline to identify randomised controlled trials (RCTs) comparing onlay versus sublay mesh repair for incisional hernias. We identified six RCTs that included 986 patients, of whom 503 were in the onlay group and 485 were in the sublay group. There was no statistically significant difference in hernia recurrence between the onlay and sublay groups (odds ratio (OR): 1.3 (0.49-3.47), 95% confidence interval (CI), p=0.60). Seroma formation was significantly higher in the onlay group (OR: 2.85 (1.74-4.67), 95% CI, p<0.0001). There were 45 reported cases of surgical site infection (SSI). There was no significant difference between the two groups (OR: 1.46 (0.44-4.84), 95% CI, p=0.54). Haematomas were reported in 11 cases, and there was no significant difference between the two groups (OR: 2.13 (0.56-8.19), 95% CI, p=0.27). Four RCTs reported the length of the hospital stay. There was no significant difference between the two groups (mean difference (MD): 0.53 (-0.16-1.22), 95% CI, p=0.13). We failed to draw conclusive clinical recommendations due to the variability in the included RCTs. We recommend well-structured, large-volume RCTs to better compare these two surgical techniques.