The number of obese individuals worldwide continues to increase every year, thus, the number of bariatric/metabolic operations performed is on a constant rise as well. Beside exclusively restrictive procedures, most of the bariatric operations have a more or less malabsorptive component. Several different bypass procedures exist alongside each other today and each type of bypass is performed using a distinct technique. Furthermore, the length of the bypassed intestine may differ as well. One might add that the operations are performed differently in different parts of the world and have been changing and evolving over time. This review evaluates the most frequently performed bariatric bypass procedures (and their variations) worldwide: Roux-en-Y Gastric Bypass, One-Anastomosis Gastric Bypass, Single-Anastomosis Duodeno-Ileal Bypass + Sleeve Gastrectomy, Biliopancreatic Diversion + Duodenal Switch and operations due to weight regain. The evaluation of the procedures and different limb lengths focusses on weight loss, remission of comorbidities and the risk of malnutrition and deficiencies. This narrative review does not aim at synthesizing quantitative data. Rather, it provides a summary of carefully selected, high-quality studies to serve as examples and to draw tentative conclusions on the effects of the bypass procedures mentioned above. In conclusion, it is important to carefully choose the procedure and small bowel length excluded from the food passage suited best to each individual patient. A balance has to be achieved between sufficient weight loss and remission of comorbidities, as well as a low risk of deficiencies and malnutrition. In any case, at least 300 cm of small bowel should always remain in the food stream to prevent the development of deficiencies and malnutrition.

Introduction: Sleeve gastrectomy (SG) is the most common bariatric operation with over 340,000 procedures per year. There are only few studies presenting follow-up results >10 years in the literature today. The aim of this study was the objective evaluation of long-term outcomes of at least 15 years after SG in non-converted patients. Methods: This study (multicenter cross-sectional; university-hospital based) includes all non-converted patients with primary SG before December 2005 at participating bariatric centers. The following methods were used: gastroscopy, esophageal manometry, 24-h pH-metry, and Gastrointestinal Quality of Life Index (GIQLI). Results: After removing converted patients, patients with bariatric procedures before SG, and deceased patients from the cohort, 20 of 53 participants have met the inclusion criteria. Of this group, 55% are suffering from symptomatic gastroesophageal reflux disease (GERD); 45% are without GERD. Esophagitis, hiatal hernias, Barrett’s esophagus, and enlarged sleeves were found in 44%, 50%, 13%, and 69% of patients during gastroscopy. Mean lower esophageal sphincter pressure was normal at 20.2 ± 14.1 mm Hg during manometry. Reflux activity in 24 h, number of refluxes, and DeMeester score were increased at 12.9 ± 9.7%, 98.0 ± 80.8, and 55.3 ± 36.3 during 24-h pH-metry. Patients with GERD scored significantly lower in the GIQLI than patients without GERD: 107.6 ± 18.4 versus 127.6 ± 14.4 (p = 0.04). Discussion/Conclusion: Fifteen years after primary SG, objective testing has shown that GERD, esophagitis, and Barrett’s esophagus are major issues for these patients. Surveillance endoscopies at 5-year intervals in all SG patients and 3-year intervals in patients with Barrett’s esophagus are recommended.

Summary: Background: Obesity impacts the diagnostic accuracy of shear wave elastography (SWE). A deep abdominal ultrasound transducer (DAX) capable of point (pSWE) and two‐dimensional (2D)‐SWE has recently been introduced to address this issue.Methods: We performed a prospective study in a cohort of mostly patients with obesity undergoing liver biopsy with a high prevalence of metabolic dysfunction‐associate steatotic liver disease (MASLD). Liver stiffness measurement (LSM) was measured using vibration‐controlled transient elastography (VCTE), as well as pSWE and 2D SWE on the standard (5C1) and the DAX transducers.Results: We included 129 patients with paired LSM and liver biopsy: median age 44.0 years, 82 (63.6%) women, median BMI: 43.2 kg/m². Histologic fibrosis stages: F0: N = 55 (42.6%), F1: N = 14 (10.9%), F2: N = 50 (38.8%), F3: N = 2 (1.6%), F4: N = 8 (6.2%). VCTE‐LSM failed (N = 13) or were unreliable (IQR/median ≤30% in ≥7.1 kPa, N = 14) in 20.9% of patients. The Pearson correlation of reliable VCTE‐LSM with both pSWE and 2D SWE was strong (all >0.78). The diagnostic accuracy for all LSM techniques was poor for significant fibrosis (≥F2, AUC: 0.54–0.63); however, it was good to excellent for advanced fibrosis (≥F3, AUC: 0.87–0.99) and cirrhosis (F4, AUC: 0.86–1.00). In intention‐to‐diagnose analysis, pSWE on DAX was significantly superior to VCTE‐LSM.Conclusions: pSWE‐ and 2D‐SWE enable the non‐invasive identification of advanced fibrosis and cirrhosis in patients with obese MASLD. The use of the DAX transducer for acoustic radiation force imaging (ARFI)‐LSM avoids technical failures in an obese population and subsequently offers advantages over VCTE‐LSM for the evaluation of fibrosis in an obese MASLD population at risk for fibrosis.

Background: Roux-en-Y gastric bypass may present long-term complications that require revisional surgery or even reversal to normal anatomy. Data on the indications, surgical technique, and outcomes of RYGB reversal remain scarce. Methods: We identified 48 cases of RYGB reversals with complete 90-day follow-up within a multi-centric international retrospective database of elective secondary bariatric surgery. The operations were performed between 2010 and 2024 in high-volume referral centers in Europe and USA. Data were collected on body weight, associated diseases, and on surgical outcomes up to 1-year postoperatively. Results: Patients were mainly female (81.3%) with a median age of 50 years (IQR 39–56). RYGB reversal was performed 7 years (median) after primary RYGB in patients with a BMI of 23.9 kg/m² (IQR 20–27). Half of the patients underwent at least 1 bariatric revision before the reversal. Main indications for reversal were dumping syndrome (33.3%), excessive weight loss (29.2%), marginal ulcer (14.6%), malabsorption (12.5%), and abdominal pain (10.4%). Rate of conversion to open surgery was 8.3%, and the postoperative complications during the first year reached 50%, including 31.3% Clavien-Dindo grade I–II, 16.7% grade III–IV complications, and one death. At 1 year, the mean BMI of the cohort increased by 18% to 28.25 kg/m²; only 1 patient reached pre-RYGB BMI. Conclusion: Although RYGB is a theoretically reversible procedure, normal anatomy is re-established only in selected cases which are refractory to medical therapy and often also to revisional bariatric surgery. RYGB reversals entail high morbidity, while the extent of recurrent weight gain at 1-year post-reversal seems to allow patients to remain below the threshold of severe obesity.

Blood glucose is lower in mountain dwellers living under low partial oxygen pressure. We show that obese mice maintained under hypoxia exhibit a delayed but distinct decrease in blood glucose with improved insulin sensitivity, which is independent of changes in body weight. This effect of hypoxia is mediated by erythropoiesis and is a direct result of the rising hematocrit, which could be due to erythrocytes acting as carriers of glucose units in the blood. Glucose lowering by the red cell mass is evidenced by a prompt decrease in glycemia in mice receiving a blood transfusion. Furthermore, life under hypoxia as well as treatment with erythropoietin reduce glycemia also in mice expressing the erythropoietin receptor exclusively in hematopoietic cells, which contrasts with previous assumptions attributing metabolic actions of erythropoietin to direct action on nonhematopoietic tissues. Our results provide a rationale for associations between hematocrit and blood glucose in humans under anti-anemic therapy, polycythemia, smoking, and high-altitude exposure.

Purpose: To evaluate HPV and p16^ink4a status as prognostic factors in patients with invasive vulvar cancer. Methods: Retrospective analysis of disease-free (DFS) and disease-specific survival (DSS) of patients with invasive vulvar cancer at a single tertiary care center. Histology, HPV and p16^ink4a status were evaluated in the context of a global multicenter trial. Logistic regression models were performed to identify the impact of p16^ink4a positivity. Results: 135 patients were included in the analysis. 32 (23.7%) showed a p16^ink4a expression of over 25%. Disease-free and disease-specific survival was longer in p16^ink4a positive patients (23 vs. 10 months, p = 0.004, respectively, 29 vs. 21 months, p = 0.016). In multivariate analysis, p16^ink4a positivity was an independent parameter for DFS (p = 0.025, HR: 2.120 (1.100–4.085)), but not for DSS (p = 0.926, HR: 1.029 (0.558–1.901), in contrast to age and tumor stage. Conclusions: Age and tumor stage negatively affect survival. However, disease-free survival is significantly longer in patients with p16^ink4a positive invasive vulvar cancer.