Risk factors for incisional hernia after open abdominal aortic aneurysm repair: a systematic review and meta-analysis

Background: The incidence of incisional hernia (IH) after an open abdominal aortic aneurysm (AAA) repair can reach up to 35%, contributing to long-term morbidity. Individual studies have been limited in identifying modifiable risk factors for IH after an open AAA repair. This meta-analysis aims to review all the risk factors for IH after an open AAA repair. Methods: We searched Cochrane Central, Embase, PubMed, MEDLINE, and Web of Science databases for original studies. Risk factors assessed were age, sex, comorbidities, surgical incision, blood loss, and surgical site infection (SSI). Data analysis was done using RStudio 4.1.2. We computed Relative Risk (RR) for dichotomous outcomes and Mean differences (MD) with 95% Confidence Interval (CI) for continuous outcomes. P-values less than 0.05 were considered statistically significant. Results: Ten studies met the inclusion criteria among 1,795 screened articles. Among those ten studies, there were a total of 1,806 patients of which 341 patients developed IH. Older age (Mean 69.6–70.7 years, MD 1.39 years, CI [1.12–1.66], P < 0.01), midline vertical incision (RR 1.55, CI [1.06–2.25], P = 0.02) and increased intraoperative blood loss (MD 429.8 ml, CI [234.8- 624.8], P < 0.01) were associated with an increased incidence of IH. Surgical site infection (SSI) was noted as a risk factor for IH after open AAA repair (RR 2.36, CI [1.31–4.24], P = 0.004). No statistically significant association was found between the incidence of IH and sex (RR 1.0, CI [0.8–1.14], P = 0.98), smoking (RR 1.01, CI [0.93–1.09], P = 0.88), diabetes (RR 1.38, CI [0.85–2.25], P = 0.19), and chronic kidney disease (RR 1.55, CI [0.47–5.09], P = 0.46). Conclusion: This meta-analysis shows that age, midline vertical incision, intraoperative blood loss, and SSI are risk factors for IH after open AAA repair.