The effect of mesenteric defect closure on internal hernias and small bowel obstruction in patients undergoing colorectal surgery: A systematic review and meta-analysis

Objective Internal hernias (IH) are potentially severe complications after colorectal surgery and may lead to small bowel obstruction (SBO). However, the impact of mesenteric defect closure (MDC) on IH and SBO is currently unclear. The aim of this systematic review and meta-analysis was, therefore, to investigate the effect of MDC on IH and SBO in patients undergoing laparoscopic and open colorectal surgery. Methods Ovid Medline, PubMed, and Embase databases were searched. Studies reporting MDC in colorectal surgery were enclosed in the systematic review. Meta-analysis included studies that assessed the effect of MDC vs. non-closure (non-MDC) on IH and SBO. Meta-analysis was performed using a random effect model. Results of individual studies were summarized as ranges. Effect sizes were described as odds ratios (OR) with 95% confidence intervals (CI). Results Literature search revealed a total of 344 abstracts. Of these, 16 studies met the inclusion criteria. Included studies comprised a total of 10,068 patients and were published between 2009 and 2019. The incidence of IH and SBO as a composite outcome ranged from 0.0 to 3.5%, whereas the incidence of IH and SBO as single outcomes ranged from 0.0 to 2.7% and 0.0 to 1.7%, respectively. If IH occurred, reoperation was required in 66-100% with additional bowel resections in 20-100% and stoma-formation in 17-50%. The complication rate after reoperations was 25-100% and mortality 0-25%. Meta-analysis including four studies revealed no statistically significant effect of MDC on the composite outcome of IH and SBO (OR 0.25, 95% CI 0.04-1.77) and SBO as a single outcome (three studies, OR 0.48, 95% CI 0.04-5.49). The risk for IH as a single outcome was significantly lower in the MDC group (three studies, OR 0.15, 95% CI 0.02-0.92). Heterogeneity of the studies included was low to moderate for the composite outcome, as well as for IH and SBO as single outcomes (I2 40.3%, 0.0%, and 45.7%, respectively). Conclusion In current meta-analysis, MDC was not significantly associated with the composite outcome of IH and SBO in patients undergoing colorectal surgery. However, MDC significantly reduced the risk for IH. Based on these results, the benefit of MDC in colorectal surgery remains unclear and needs to be addressed in further studies.