What is the ideal mesh location for incisional hernia prevention during elective laparotomy? A network meta-analysis of randomized trials

Background: Incisional hernia (IH) represents an important complication after surgery. Prophylactic mesh reinforcement (PMR) with different mesh locations [onlay (OL), retromuscular (RM), preperitoneal (PP), and intraperitoneal (IP)] has been described to possibly reduce the risk of postoperative IH. However, data reporting the 'ideal' mesh location are sparse. The aim of this study was to evaluate the optimal mesh location for IH prevention during elective laparotomy. Methods: Systematic review and network meta-analysis of randomized controlled trials (RCTs). OL, RM, PP, IP, and no mesh (NM) were compared. The primary aim was postoperative IH. Risk ratio (RR) and weighted mean difference (WMD) were used as pooled effect size measures, whereas 95% credible intervals (CrI) were used to assess relative inference. Results: Fourteen RCTs (2332 patients) were included. Overall, 1052 (45.1%) had no mesh (NM) while 1280 (54.9%) underwent PMR stratified in IP (n = 344 pts), PP (n = 52 pts), RM (n = 463 pts), and OL (n = 421 pts) placement. Follow-up ranged from 12 months to 67 months. RM (RR = 0.34; 95% CrI: 0.10-0.81) and OL (RR = 0.15; 95% CrI: 0.044-0.35) were associated with significantly reduced IH RR compared to NM. A tendency toward reduced IH RR was noticed for PP versus NM (RR = 0.16; 95% CrI: 0.018-1.01), while no differences were found for IP versus NM (RR = 0.59; 95% CrI: 0.19-1.81). Seroma, hematoma, surgical site infection, 90-day mortality, operative time and hospital length of stay were comparable among treatments. Conclusions: RM or OL mesh placement seems associated with reduced IH RR compared to NM. PP location appears promising; however, future studies are warranted to corroborate this preliminary indication.