Prophylactic Mesh Reinforcement Versus Primary Suture for Abdominal Wall Closure after Elective Abdominal Aortic Aneurysm Repair with Midline Laparotomy Incision: Updated Systematic Review Including Time- To-Event Meta-Analysis and Trial Sequential Analysis of Randomized Controlled Trials

Background: Patients undergoing open abdominal aortic aneurysm (AAA) repair have a high risk of incisional hernia. Heterogeneity in recommendations regarding prophylactic mesh reinforcement between scientific society guidelines reflects the lack of sufficient data, with the Society for Vascular Surgery making no recommendation on methods for abdominal wall closure. We aimed to synthesize the most current evidence on mesh versus primary suture abdominal wall closure after open AAA repair. Methods: A systematic review was conducted on randomized controlled trials (RCTs) comparing mesh reinforcement with primary abdominal wall closure for patients who underwent elective AAA repair with a midline laparotomy incision. Dichotomous and time-to-event data were pooled using random effects models, applying the Mantel-Haenszel or inverse variance statistical method. The revised Cochrane tool and Grades of Recommendation, Assessment, Development, and Evaluation framework were used to assess the risk of bias and certainty of evidence, respectively. Trial sequential analysis assumed alpha = 5% and power = 80%. Results: Five RCTs were included reporting a total of 487 patients (260 in the mesh group and 227 in the primary suture group). Patients who had mesh closure had statistically significantly lower odds of developing incisional hernia after open AAA repair than those with primary suture closure (odds ratio (OR) 0.20, 95% confidence interval (CI) 0.09-0.43). Time-to-event analysis confirmed that the hazard of incisional hernia was statistically significantly lower in patients who had mesh closure (P < 0.05). Meta-analysis found statistically significantly lower odds of reoperation for incisional hernia in the mesh group (OR 0.23, 95% CI 0.06-0.93), but there was no statistically significant difference in wound infection (risk difference 0.02, 95% CI -0.03-0.08).The overall risk of bias was low in one study, high in 2 studies, ''some concerns" in 2 studies for incisional hernia and reoperation for incisional hernia, and high in all studies reporting wound infection. The certainty of evidence was judged to be low for all outcomes. Trial sequential analysis confirmed a benefit of mesh reinforcement in reducing the risk of incisional hernia. Conclusions: Meta-analysis of the highest-level data demonstrated a benefit of prophylactic mesh reinforcement, with trial sequential analysis confirming no additional RCTs required. This provides compelling evidence to support the use of mesh for midline laparotomy closure in patients undergoing open AAA repair.