Internal hernia trends following gastric bypass surgery

Background Internal hernia is a well-known complication of laparoscopic Roux-en-Y gastric bypass (LRYGB), with reported rates ~ 5% within three months to three years after surgery. Internal hernia through a mesenteric defect can lead to small bowel obstruction. Mesenteric defects began to be more routinely closed, often considered standard practice by 2010. To our knowledge, there are no large population-based studies looking at rates of internal hernia post-LRYGB. This study utilizes a statewide database to characterize the trends of internal hernia post-LRYGB over the last two decades in multiple centers. Methods LRYGB procedure records between January 2005 and September 2015 were extracted from the New York SPARCS database. Exclusion criteria included age < 18, in-hospital deaths, bariatric revision procedures, and internal hernia repair during the same hospitalization as LRYGB. Time to internal hernia was calculated from initial LRYGB hospital stay to admission date of the first internal hernia repair record. A multivariable proportional sub-distribution hazards model was utilized to analyze the trend of internal hernia incidence within three-year post-LRYGB. Results 46,918 patients were identified between 2005 and 2015, with 2950 (6.29) undergoing internal hernia repair post-LRYGB by the end of 2018. The cumulative incidence of internal hernia repair at the 3rd-year post-LRYGB was 4.80% (95% CI: 4.59%–5.02%). By the end of the 13th year, the longest follow-up period, the cumulative incidence was 12.00% (95% CI: 11.30%–12.70%). Overall, there was a decreasing trend over time of undergoing internal hernia repair within three-year post-LRYGB (HR = 0.94, 95% CI: 0.93–0.96), after adjusting for confounding factors. Conclusion This multicenter study maintains the rate of internal hernia following LRYGB reported in smaller studies and provides a longer follow-up period demonstrating decreasing occurrences of internal hernia after bypass as a function of year of index operation. This data is important as internal hernia continues to be a complication post-LRYGB. Graphical abstract