A Meta-Analysis Comparing Sublay and Onlay Mesh Repair in Incisional Hernia Surgery Based on Surgical Outcomes

Incisional hernia is a common surgical complication that often requires mesh-based repair. Among the various techniques, sublay (retrorectus) and onlay mesh placements are frequently employed, but their relative effectiveness in terms of surgical outcomes remains debated. This meta-analysis aimed to compare sublay and onlay mesh repair techniques in incisional hernia surgery based on key postoperative outcomes. A systematic search was conducted across PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, ProQuest, and Google Scholar for studies published in English between January 2010 and March 2025. Eligible studies included randomized controlled trials and prospective comparative studies directly comparing sublay and onlay mesh repair techniques and reporting on at least one predefined surgical outcome. Six studies involving a total of 468 patients were included in the analysis. Primary outcomes assessed included hernia recurrence, postoperative complications, surgical site infection (SSI), and seroma formation. Secondary outcomes included operative time and length of hospital stay. Data were analyzed using a random-effects model with odds ratios (OR) and mean differences (MD) reported along with 95% confidence intervals (CI). The meta-analysis revealed that sublay mesh repair was consistently associated with lower hernia recurrence rates, though the differences did not reach a statistical significance. Sublay repair also demonstrated significantly fewer postoperative complications in multiple studies, particularly in terms of reduced seroma formation and SSI. Furthermore, hospital stay was significantly shorter in the sublay group in two of the three studies reporting this outcome. Onlay repair, however, was associated with a shorter operative time. In conclusion, sublay mesh repair offers superior outcomes in terms of recurrence, complications, seroma, and hospital stay, suggesting it as the preferred approach for incisional hernia repair in appropriate clinical settings.