Internal hernia in patients after duodenal switch: A multi-centred comparative analysis.

Biliopancreatic diversion with duodenal switch (BPD-DS) and single anastomosis duodeno-ileostomy with sleeve (SADI-S) are associated with superior and sustained weight loss outcomes. Despite their growing popularity, long-term safety profiles, particularly the risk of internal hernia (IH), remain underexplored. This study aimed to evaluate the incidence and characteristics of IH following BPD-DS and SADI-S procedures, comparing their clinical presentation, diagnostic methods, and outcomes. A retrospective chart review was performed for patients who underwent BPD-DS or SADI-S between 2008 and 2023 in two high-volume tertiary referral centres for bariatric surgery in the United States. Demographic data, comorbidities, operative details, and follow-up outcomes were collected. A subgroup analysis of IH cases was conducted to compare the incidence, location of hernias, and diagnostic modalities between procedures. Out of 1160 patients (85.1% BPD-DS; 14.9% SADI-S), the overall incidence of IH was 1.12%, with a higher rate in BPD-DS (0.8%) than in SADI-S (0.57%). Most IHs occurred within the first 24 months postoperatively. The majority of IHs in BPD-DS patients were in the pseudo-Petersen's space. The single IH case in the SADI-S group occurred in the same space. Most patients presented with abdominal pain and were diagnosed by CT imaging. SADI-S showed a lower IH rate compared to BPD-DS, but further studies are needed to confirm these findings. The variability in clinical presentation complicates the diagnosis of IH, emphasizing the need for increased clinical vigilance.