Closure of mesenteric defects for prevention of internal hernia after Roux-en-Y gastric bypass in bariatric surgery.

Rationale: Internal hernia is one of the most severe complications observed in people undergoing Roux-en-Y gastric bypass (RYGB). There are some who advocate for the closure of defects to prevent internal hernias. However, the closure of these defects might be associated with an increased risk of small bowel obstruction, resulting from a kink in the anastomosis of the small intestines. Currently, there is a lack of robust evidence demonstrating the benefits of defect closure.

Objectives: To assess the benefits and harms of defect closure for prevention of internal hernia after Roux-en Y gastric bypass in bariatric surgery.

Search methods: We searched CENTRAL, MEDLINE, and Embase to August 2024. We reviewed the reference lists of included studies and reached out to the study authors to obtain any missing data. We also searched PubMed, grey literature in the OpenGrey database, Clinical Trials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP).

Eligibility criteria: We included randomised controlled trials (RCTs) that included people with obesity (defined as a body-mass index (BMI) ≥ 35 kg/m²) who underwent laparoscopic or robotic RYGB in bariatric surgery, and compared the closure of defects with the non-closure of defects. We excluded quasi-randomised trials, cluster-RCTs, and cross-over trials.

Outcomes: The critical outcomes assessed were the incidence of internal hernia with bowel obstruction within 10 years, the incidence of postoperative overall complications within 30 days, and the incidence of postoperative mortality within 30 days. The important outcomes included the incidence of intraoperative overall complications, length of hospital stay, and the postoperative pain resulting from gastric bypass surgery, assessed using a visual analogue scale (VAS) two years after surgery.

Risk of bias: Two review authors independently evaluated the risk of bias for each included study using the Cochrane RoB 2 tool.

Synthesis methods: Two review authors independently assessed the methodological quality and extracted data from the included trials. We performed a random-effects meta-analysis for data synthesis. We calculated risk ratios (RR) with 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) with 95% CIs for continuous outcomes. We assessed the certainty of evidence based on the GRADE approach.

Included studies: We identified three RCTs with 3010 participants, which met our inclusion criteria. The closure of mesenteric defects used non-absorbable, interrupt closure in one study, and non-absorbable running sutures in two studies.

Synthesis of results: The closure of defects during RYGB may reduce the incidence of internal hernia with bowel obstruction within 10 years compared with non-closure (RR 0.32, 95% CI 0.24 to 0.42; P < 0.00001, I² = 0 %; 3 studies, 3010 participants; low-certainty evidence). The closure of defects may result in little to no difference in the incidence of postoperative overall complications within 30 days compared to non-closure (RR 1.13, 95% CI 0.87 to 1.47; P = 0.35, I² = 0 %; 2 studies, 2609 participants; low-certainty evidence). The closure of defects may result in little to no difference in the incidence of postoperative mortality within 30 days compared to non-closure (RR 2.97, 95% CI 0.12 to 72.93; P = 0.50, I² not applicable; 2 studies, 2908 participants; very low-certainty evidence). The closure of defects may result in little to no difference in the incidence of intraoperative overall complications compared to non-closure (RR 0.87, 95% CI 0.54 to 1.42; P = 0.59, I² not applicable; 1 study, 2507 participants; very low-certainty evidence). Closure defects may lead to the longer length of hospital stay; however, the evidence is very uncertain (MD 0.27 days, 95% CI 0.15 to 0.38; P < 0.00001; I² = 93%; 2 studies, 2609 participants; very low-certainty evidence). Postoperative pain from gastric bypass surgery was not assessed because there was not enough information available for analysis.

Authors' conclusions: The closure of defects may be more effective than the non-closure of defects for prevention of internal hernia after RYGB. However, the small number of trials limited our confidence in the evidence. There is little to no difference between the closure and non-closure of defects in the incidence of postoperative overall complications, the incidence of postoperative mortality, and the incidence of intraoperative overall complications. The length of hospital stay may be longer for those undergoing defect closure than for those who did not have the defects closed. The evidence is very uncertain about the incidence of postoperative mortality, the incidence of intraoperative overall complications, and the length of hospital stay. Additional evidence based on trials designed to be at low risk of bias and with an adequate sample size is imperative.

Funding: This Cochrane review had no dedicated funding.

Registration: The protocol was registered in the Cochrane Library on 9 May 2023.