Roux-en-O misconfiguration is a rare but serious technical error in Roux-en-Y gastric bypass (RYGB), resulting from the misidentification of small bowel limbs in which the biliopancreatic limb (BPL) is incorrectly anastomosed to the gastric pouch and the jejunojejunostomy (JJ) is misconfigured, leading to functional obstruction, bile reflux, and substantial morbidity. This narrative review synthesizes the available literature on its incidence, risk factors, clinical presentation, diagnostic challenges, differential diagnosis, treatment strategies, associated morbidity, and prevention methods. Drawing from case reports and small series, we highlight the diagnostic pitfalls and surgical corrections, including innovative approaches like jejunal interposition for complicated revisions. An illustrative case of a young woman with Roux-en-O following multiple bariatric conversions, complicated by a perigastric abscess, is integrated to demonstrate real-world application. Early recognition and meticulous intraoperative verification are essential to mitigate this preventable complication, preserving the efficacy of RYGB as a benchmark bariatric procedure.

Laparoscopic sleeve gastrectomy (LSG) is associated with gastroesophageal reflux disease (GERD), but long-term esophageal mucosal changes, including Barrett's esophagus (BE), remain incompletely characterized. Symptom-based surveillance may underestimate histologic abnormalities. Prospective evaluation of a historical cohort of 50 adults who underwent primary LSG more than 8 years earlier and accepted to undergo systematic endoscopy. All included patients underwent standardized high-definition upper endoscopy with Seattle protocol biopsies regardless of symptoms. BE was defined as columnar epithelium with specialized intestinal metaplasia. GERD was assessed by symptoms and Los Angeles classification. Baseline characteristics were compared between included and non-included patients to assess selection bias. Compared to non-included patients (n = 266), included patients were older (43.2 vs. 38.5 years, p = 0.001) and had lower preoperative hiatal hernia prevalence (14% vs. 36%, p = 0.004). Sixty-six per cent were female. Weight decreased from 112.7 ± 15.3kg to 85.2 ± 17.9kg (p < 0.001), with mean %TWL of 24.2 ± 12.7%. GERD symptoms increased from 26% preoperatively to 50% at follow-up (p = 0.023); 82% were taking PPIs. Histology revealed esophagitis in 46% and BE in 4% (2/50). Significant endoscopic-histologic discordance was observed (p = 0.002): 40% had biopsy-proven esophagitis despite normal endoscopic appearance. LSG achieved durable weight loss but was associated with increased GERD symptoms and high prevalence of histologic esophagitis at more than 8 years. Marked discordance between symptoms, endoscopic appearance, and histopathology supports systematic biopsy-based surveillance after LSG, independent of symptoms or macroscopic findings.