Revisional metabolic and bariatric surgery (RBS) has evolved alongside metabolic and bariatric surgery (MBS). Patients may require reoperation after any type of MBS because of unsatisfactory treatment outcomes, weight regain, malnutrition, or postoperative complications. Based on the surgical purpose, RBS can be classified into three types: conversion, restoration, and repair. Conversion changes the primary procedure to another operation to improve weight loss and metabolic outcomes; restoration re-establishes the original anatomical or physiological state; and repair treats postoperative complications. Compared with primary surgery, RBS involves more complex anatomy, greater technical difficulty, and higher perioperative risks, thereby placing greater demands on surgeons’ theoretical knowledge, operative skills, and multidisciplinary teamwork. In recent years, the widespread use of incretin-based anti-obesity medications has substantially influenced the development of RBS, and the international volume of RBS has declined. In China, however, the volume of MBS continues to increase, and the demand for RBS may rise accordingly. Roux-en-Y gastric bypass remains one of the most widely used revisional procedures. Robotic assistance offers potential advantages in complex dissection and precise manipulation and may become an important technical platform for RBS. Appropriate patient selection, multidisciplinary assessment, and evidence-based procedure selection are essential for the safe and standardized development of RBS.
Obesity is markedly heterogeneous, and no single weight-based measure adequately captures fat distribution, metabolic risk, organ damage, and functional status. Obesity classification can complement body mass index (BMI) -based assessment, identify high-risk populations, define treatment priorities and individualized goals, and support efficacy monitoring and shared decision-making. Controversies remain over whether newer systems should replace traditional BMI-centered frameworks, how to distinguish risk states from clinical disease, whether precision phenotypes can directly guide pharmacotherapy or procedure selection, and whether complex assessments are accessible and equitable. Current consensus supports retaining BMI as a simple screening measure and an anchor for the existing evidence base, while integrating population-specific thresholds, obesity-related disease burden, organ and physical function, and specific etiologies into stratified assessment. Other classification systems should remain complementary and, at present, should not independently determine treatment eligibility or procedure selection. High-risk patients should be prioritized for care rather than excluded from treatment, and should undergo dynamic reassessment before and after treatment. Prospective, outcome-oriented studies should validate the reproducibility, predictive value, and clinical utility of different classification systems.
Weight regain after metabolic and bariatric surgery (MBS) is one of the most challenging clinical problems in bariatric surgery and the leading indication for revisional surgery. A unified definition of post-MBS weight regain remains lacking, and weight regain must be strictly distinguished from insufficient weight loss and a weight-loss plateau. Weight regain is driven jointly by anatomical abnormalities, behavioral and psychological factors, metabolic adaptation, medication-related effects, and inadequate follow-up management; among these factors, anatomical abnormalities are the only causes that can be directly corrected surgically. Before revisional surgery, patients must undergo systematic reassessment by a multidisciplinary team (MDT) and follow a four-tiered, stepwise intervention pathway comprising intensive lifestyle intervention, anti-obesity medication, endoscopic intervention, and revisional surgery. Revisional surgery should be individualized, etiology directed, and based on a careful risk-benefit assessment, with the procedure selected according to the primary operation and the cause of weight regain. Roux-en-Y gastric bypass (RYGB) is preferred for patients with weight regain and refractory gastroesophageal reflux disease after sleeve gastrectomy. Revisional sleeve gastrectomy (ReSG) or sleeve gastrectomy with transit bipartition (SG-TB) may be considered for patients with marked dilation of the gastric remnant. When weight loss is the primary goal, procedures such as single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) provide superior weight-loss outcomes. Contraindications to revisional surgery must be strictly assessed, and the procedure should be performed at experienced bariatric centers. Coordinated surgical and pharmacological management centered on glucagon-like peptide-1 (GLP-1) receptor agonists or dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 receptor agonists emphasizes early warning, intervention before a weight-loss plateau, and combination strategies, which may enable more patients with weight regain to achieve the greatest benefit with the least trauma.
Revisional metabolic and bariatric surgery (RBS) is an important clinical intervention after an unsatisfactory outcome of primary bariatric surgery or the occurrence of serious complications.The reasons for revision and the therapeutic goals are highly heterogeneous. Conventional outcome assessment based solely on the magnitude of weight loss no longer meets diverse clinical diagnosis and treatment needs. An objective appraisal of the clinical value of RBS must begin by identifying the specific reason for revision. For inadequate weight loss or weight regain, refractory gastroesophageal reflux disease, dysphagia, gastrointestinal leak or fistula, severe malnutrition, and other revisional indications, core outcomes should be defined individually rather than judged against a single absolute threshold for success. A systematic, multidimensional framework should encompass weight control, outcomes in obesity-related comorbidities, perioperative safety, long-term nutritional status, the rate of reintervention, and health-related quality of life. The type of revisional procedure and the concomitant use of weight-loss medication, endoscopic therapy, and intensive lifestyle intervention should also be documented in a standardized manner to distinguish the contribution of surgery itself from that of comprehensive treatment. The time origin for weight-related follow-up should be standardized: the additional weight-loss effect should be calculated from body weight before revision, whereas the cumulative weight-loss effect should be calculated from body weight before the primary procedure. Clinical registries and research reports should fully report key weight parameters, the actual number of patients assessed at each follow-up point, and reasons for loss to follow-up to reduce selective reporting and attrition bias. Establishing standardized follow-up for more than 5 years, together with a multidisciplinary collaborative comprehensive management model, can facilitate the integration of RBS into life-course management pathway for patients with obesity.
The short-term safety and long-term efficacy of Roux-en-Y gastric bypass depend not only on procedure selection but also on standardized operative technique, appropriate limb-length design, and lifelong nutritional management. An improperly shaped gastric pouch, inadequate anastomotic perfusion or excessive tension, incorrect limb orientation, and incomplete closure of mesenteric defects may result in leakage, bleeding, stenosis, obstruction, or internal hernia. Insufficient small-bowel bypass may compromise weight loss and metabolic improvement, whereas excessive bypass increases the risks of protein-energy malnutrition, anemia, and micronutrient deficiencies. Gastric-pouch construction should balance volume, configuration, perfusion, and complete separation from the remnant stomach. Small-bowel measurement requires standardized instruments, start and end points, and traction. Gastrojejunostomy and jejunojejunostomy should have adequate perfusion, an appropriate diameter, and minimal tension, and mesenteric defects should be routinely closed. For most primary proximal procedures, a biliopancreatic limb of 50-100 cm and an alimentary limb of 100-150 cm are practical reference ranges. In patients with greater metabolic needs and a low nutritional risk, selective lengthening of the biliopancreatic limb to 100-150 cm may be considered. More intensive bypass or revisional surgery requires measurement of the total small-bowel length and integrated assessment of the common channel, total alimentary limb length, nutritional reserve, and adherence to follow-up. Individualized limb-length selection must be based on standardized technique and combined with lifelong nutritional supplementation and biochemical monitoring to balance metabolic benefits against long-term nutritional safety.
Refractory gastroesophageal reflux disease (r-GERD) is one of the major long-term complications after metabolic and bariatric surgery (MBS), and it seriously affects surgical outcomes and the quality of life of patients. Its pathogenesis involves postoperative anatomical changes, esophageal motility disorders, persistence of preoperative high-risk factors and postoperative triggers, and the superposition of these factors greatly increases the complexity of diagnosis and treatment. Symptoms of post-MBS r-GERD are mainly heartburn and reflux, whereas some patients present only with extra-esophageal symptoms; its diagnosis should be based on objective confirmation of pathological reflux. Precise assessment is the prerequisite and individualized decision-making is the key. On the basis of stepwise evaluation with symptom and quality-of-life questionnaires, endoscopy, upper gastrointestinal barium contrast study and thin-slice CT, and 24-h esophageal pH-impedance monitoring combined with high-resolution manometry, a multidisciplinary team should clarify the characteristics of reflux, the type of anatomical abnormality and the functional status of the esophagogastric unit. Strict indications are required for revisional surgery, and the revisional procedure should be individualized according to the primary operation, the type of anatomical deformity and the reflux characteristics, taking both anti-reflux efficacy and weight-loss and metabolic benefits into consideration. Conversion to Roux-en-Y gastric bypass currently provides the most robust evidence and the most definitive effect, and further optimization of the assessment process and revisional strategies remains the direction of future work.
Metabolic and bariatric surgery is an effective treatment for severe obesity and related metabolic diseases. Single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S), a simplified modification of biliopancreatic diversion with duodenal switch (BPD-DS), reduces surgical complexity by eliminating one anastomosis and preserving pyloric function while maintaining favorable weight-loss and glycemic outcomes. However, postoperative malnutrition, particularly refractory hypoproteinemia and micronutrient deficiencies, remains a major limitation to its widespread use. Malnutrition after SADI-S is closely associated with malabsorption caused by an excessively short common channel, reduced intake resulting from decreased gastric capacity and gastrointestinal hormonal changes, additional nutrient loss due to diarrhea, and marked interindividual variation in total small bowel length. Common channel length is a key determinant of nutritional risk. Revisional surgery should be considered for patients with severe hypoproteinemia, intractable diarrhea, or malnutrition-associated liver disease who are refractory to conservative treatment such as dietary modification and nutritional supplementation. Common channel elongation is the most frequently used revisional procedure; it can correct hypoproteinemia and relieve diarrhea while preserving part of the weight-loss effect. Duodeno-duodenostomy or conversion to a Roux-en-Y configuration may be used as salvage procedures in life-threatening cases. Adequate preoperative nutritional optimization, precise intraoperative measurement of total small bowel length, and close multidisciplinary postoperative follow-up are essential for successful revision. Individualized common channel design based on the proportion of total small bowel length may help balance weight-loss efficacy and nutritional risk and represents an important direction for further optimization of SADI-S.
Bariatric surgery achieves substantial short- and medium-term weight loss in patients with severe obesity and improves metabolic comorbidities such as type 2 diabetes, hypertension, and obstructive sleep apnea. However, postoperative weight regain has become a major challenge to durable outcomes. Its mechanisms are multifactorial and include anatomical changes, such as gastric pouch dilatation or anastomotic enlargement; alterations in hunger- and satiety-related hormones; adaptive reductions in basal metabolic rate; and recurrence of adverse dietary, insufficient physical activity, and psychological behaviors. Revision surgery can correct selected structural defects and achieve additional weight loss but is limited by higher perioperative risks, strict indications, and the possibility of recurrent weight regain. Anti-obesity medications, particularly glucagon-like peptide-1 receptor agonists, have demonstrated clinically meaningful efficacy in managing postoperative weight regain. Existing studies have shown that semaglutide, liraglutide, and other agents can reduce postoperative body weight and BMI, with more pronounced effects after longer intervention. Other agents may be considered when glucagon-like peptide-1 receptor agonists are contraindicated or not tolerated, although their long-term medication safety and weight regain after discontinuation remain concerns. Patients with severe weight regain, clear anatomical abnormalities, or an inadequate response to medication should undergo multidisciplinary evaluation for revision surgery. Individualized stratification according to the magnitude and cause of weight regain, drug contraindications, and surgical risks, combined with a stepwise “medication-first—efficacy evaluation—surgical re-decision” strategy or perioperative pharmacological adjuncts, may maximize the complementary effects of pharmacotherapy and revision surgery and improve long-term weight management.
As the volume of metabolic and bariatric surgery continues to increase, postoperative weight regain, inadequate control of metabolic diseases, and long-term complications have become important factors affecting patients’ long-term benefits. Complex revisional metabolic and bariatric surgery is an important option for addressing these problems. However, anatomical alterations caused by previous procedures, individual differences in patients’ clinical conditions, and increased perioperative risks complicate preoperative assessment, selection of revisional procedures, surgical planning, and postoperative management, thereby placing greater demands on the accuracy and standardization of clinical decision-making. Artificial intelligence (AI) can integrate and analyze clinical data, imaging findings, endoscopic information, and follow-up data to provide multidimensional support for individualized decision-making in complex revisional surgery. Its potential applications encompass comprehensive preoperative assessment, perioperative risk prediction, selection of revisional procedures, three-dimensional assisted planning, intraoperative decision support, and postoperative follow-up management, spanning multiple stages of surgical planning and management. Although AI has an established research foundation in medical image analysis and surgical risk prediction, studies directly addressing complex revisional metabolic and bariatric surgery remain scarce, and the clinical value of relevant models requires further validation. The lack of standardized data collection, processing, and annotation; insufficient multicenter studies and clinical validation; limited model interpretability; and unclear boundaries of medical liability remain major barriers to clinical implementation. Future efforts should strengthen the development of metabolic and bariatric surgery databases, advance clinical validation, improve AI regulatory frameworks, and facilitate the effective integration of AI technologies with surgeons’ professional judgment. As a decision-support tool for surgeons, AI may improve the precision of assessment and planning, and promote the development of complex revisional metabolic and bariatric surgery toward greater precision and standardization.
Objective To compare the incidence of postoperative pancreatic fistula (POPF) between main pancreatic duct ligation combined with hand-sewn closure and stapler closure of the pancreatic stump during laparoscopic distal pancreatectomy (LDP), and to identify independent factors associated with POPF. Methods The clinical data of 757 patients who underwent LDP at the Department of Pancreatic Surgery, Zhongshan Hospital, Fudan University, from January 2023 to April 2026 were retrospectively analyzed. The patients were divided into the stapler closure group (n=690) and the main pancreatic duct ligation combined with hand-sewn closure group (hand-sewn group, n=67) according to the method of pancreatic stump closure. The primary analysis used multivariable Logistic regression to identify independent factors associated with POPF; nearest-neighbor propensity score matching (PSM) at a maximum ratio of 1:5 was performed as a sensitivity analysis, and conditional Logistic regression was used to compare outcomes between the matched groups. Results The overall incidence of POPF was 37.0% (280/757), including 278 cases (36.7%) of grade B POPF and 2 cases (0.3%) of grade C POPF. No in-hospital death occurred. The incidence of POPF was 38.4% (265/690) in the stapler closure group and 22.4% (15/67) in the hand-sewn group (P=0.011). Multivariable Logistic regression showed that main pancreatic duct ligation combined with hand-sewn closure was independently associated with a lower risk of POPF (OR=0.46, 95%CI 0.25-0.87, P=0.017), whereas hypertension was an independent risk factor (OR=1.66, 95%CI 1.13-2.43, P=0.009). After PSM, conditional Logistic regression showed that the risk of POPF was lower in the hand-sewn group than in the stapler closure group (OR=0.45, 95%CI 0.22-0.90, P=0.025). No statistically significant differences were found between the two groups in postoperative percutaneous drainage, reoperation, severe complications, or postoperative length of hospital stay (all P>0.05). Conclusion Main pancreatic duct ligation combined with hand-sewn closure of the pancreatic stump is associated with a lower incidence of POPF after LDP compared with stapler closure; hypertension is an independent risk factor for POPF.
Objective To compare the perioperative efficacy and safety of indocyanine green (ICG) fluorescence-guided transumbilical single-port and traditional multi-port laparoscopic cholecystectomy, so as to provide a basis for surgical procedure optimization and clinical selection. Methods Clinical data of patients who underwent laparoscopic cholecystectomy in the Department of Hepatobiliary and Pancreatic Surgery of Hebei General Hospital from January 2023 to February 2025 were retrospectively included. According to the surgical procedure, the patients were divided into a single-port group and a multi-port group. Propensity score matching (PSM) was used for 1:1 matching, obtaining 50 pairs of comparable samples. The operative time, intraoperative blood loss, postoperative hospital stay, usage rate of analgesics within 24 h postoperatively, and postoperative liver function indicators, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), were compared between the two groups. Results After matching, there was no statistically significant difference in baseline characteristics between the two groups. The operative time in the single-port group was longer than that in the multi-port group [90 (80, 105) min vs. 69 (55, 90) min], and the intraoperative blood loss was lower than that in the multi-port group [5 (2, 5) mL vs. 5 (2.75, 6.25) mL], with statistically significant differences (both P<0.05).The usage rate of analgesics within 24 h postoperatively in the single-port group was lower than that in the multi-port group (40% vs. 66%, P<0.05).Comparison of postoperative liver function showed that the levels of ALT and AST in the single-port group were lower than those in the multi-port group [ALT: 26.600 (15.300, 43.150) U/L vs. 42.550 (29.850, 62.200) U/L; AST: 29.550 (19.500, 39.925) U/L vs. 44.650 (32.700, 56.875) U/L], with statistically significant differences (both P<0.05).There was no statistically significant difference in postoperative hospital stay between the two groups [4 (3, 4) d vs. 4 (3, 5) d, P>0.05]. No severe complications such as biliary leakage, common bile duct injury, reoperation for bleeding, or incisional infection were observed in either group. Conclusion Under comparable baseline conditions, single-port laparoscopic cholecystectomy has lower analgesic requirements, less intraoperative blood loss, and better postoperative liver function indicators than the traditional multi-port procedure, with comparable overall safety; its main disadvantage is prolonged operative time. Combining the efficacy and safety results, the single-port procedure under ICG fluorescence navigation can serve as an effective complementary option to the traditional multi-port procedure.
Objective To investigate the clinical characteristics of patients with gastric cancer and peritoneal metastasis (GCPM) and the associations of different treatment modalities with prognosis, thereby providing evidence for individualized clinical decision-making. Methods The clinical data of 173 patients with synchronous GCPM and no other distant metastases who were treated at The First Hospital of Jilin University between 2015 and 2024 were retrospectively analyzed. According to the treatments actually received, the patients were divided into six groups: chemotherapy alone; chemotherapy plus hyperthermic intraperitoneal chemotherapy (HIPEC); chemotherapy plus immunotherapy; chemotherapy plus immunotherapy and HIPEC; chemotherapy plus HIPEC and surgery; and chemotherapy plus HIPEC, surgery, and immunotherapy. Overall survival (OS) was estimated using the Kaplan-Meier method, and intergroup differences were compared using the Log-rank test. Pairwise comparisons were adjusted using the Holm method. Cox regression models were used to analyze prognostic factors. Because surgery was performed during the course of treatment, it was modeled as a time-dependent covariate. An extended Cox model was constructed according to the results of the proportional hazards assumption test, and a 6-month landmark sensitivity analysis was also performed. Follow-up ended on February 10, 2026. Results Among the 173 patients, 147 died during follow-up. The median follow-up time was 31.13 months, and the median OS was 13.57 months (95% CI 11.98-15.16 months).The median OS values in the six treatment groups were 4.10, 9.80, 12.57, 12.50, 16.40, and 18.60 months, respectively, with a statistically significant overall difference (P<0.001). After Holm adjustment, the chemotherapy plus HIPEC and surgery group differed significantly from the chemotherapy-alone group and showed a trend toward a survival advantage over the other three nonsurgical treatment groups. The chemotherapy plus HIPEC, surgery, and immunotherapy group differed significantly from all four nonsurgical treatment groups. Descriptive analysis showed that the median OS was longer in the surgery group than in the nonsurgery group (17.20 months vs.12.07 months, P<0.001). Univariable time-dependent Cox analysis showed that surgery was associated with a lower risk of death (HR=0.428, 95%CI 0.293-0.624, P<0.001).Multivariable extended Cox analysis indicated that the effect associated with surgery was time dependent (surgery-by-time interaction, P=0.027). In the 6-month landmark analysis, after adjustment for baseline factors, the difference in mortality risk between the surgery and nonsurgery groups was not statistically significant (HR=0.802, 95%CI 0.516-1.248, P=0.328). Univariable Cox analysis showed that both HIPEC (HR=0.457, 95%CI 0.325-0.643, P<0.001) and immunotherapy (HR=0.627, 95%CI 0.451-0.870, P=0.005) were associated with a lower risk of death. Multivariable extended Cox analysis showed that anemia, cT4b stage, and cN3b stage were associated with a higher risk of death. Conclusion OS differed among patients with GCPM who received different treatment modalities, and multimodal treatment regimens incorporating HIPEC and surgery were associated with favorable survival outcomes. In univariable analyses, HIPEC and immunotherapy were associated with a lower risk of death; the survival advantage associated with surgery was attenuated after treatment timing and baseline factors were taken into account. Anemia, cT4b stage, and cN3b stage were associated with poorer prognosis. These findings represent observational associations and should not be interpreted as evidence of independent causal effects of specific treatment modalities.
Objective To explore the clinical characteristics, key aspects of diagnosis and treatment, and preventive strategies for postgastrectomy internal hernia (PIH), providing a reference for standardized clinical diagnosis and treatment. Methods A retrospective analysis was conducted on the clinical data of 117 patients with PIH admitted to four medical centers, namely the First Hospital of Nanchang, the First People’s Hospital Fuzhou, the First Affiliated Hospital of Nanchang University and Shangrao People’s Hospital, from January 2020 to December 2025, to summarize their clinical characteristics, diagnosis and treatment, and prognosis. Results Most patients were elderly, emaciated men, with a median age of 67 years; 73.50% were aged ≥60 years, and 39.32% were emaciated. Laparoscopic distal gastrectomy was the predominant prior operation, and Billroth Ⅱ reconstruction was the most common gastrointestinal reconstruction procedure. Petersen’s hernia was the predominant type (81.20%), and more than half of the patients developed PIH within 3 years after gastrectomy. Mesenteric defects had been closed during the index gastrectomy in only 38.46% of patients. Sudden, severe abdominal pain was the main presenting symptom. Contrast-enhanced abdominal CT was the first-line diagnostic modality, with a detection rate of 94.87% for typical signs. All patients underwent surgery, predominantly emergency open surgery; 17.09% required bowel resection and anastomosis. The postoperative complication rate was 15.38%, and the mortality rate was 1.71%. Closure of mesenteric defects during the initial operation reduced the incidence of bowel resection during reoperation. Conclusion PIH has an acute onset and rapid progression. In this cohort, PIH was predominantly seen in elderly, emaciated men who had previously undergone laparoscopic gastrectomy with Billroth Ⅱ reconstruction. Contrast-enhanced abdominal CT facilitates early diagnosis, and timely surgery is critical for improving prognosis. Routine closure of mesenteric defects during gastrectomy is recommended to prevent PIH and lower the rate of bowel resection during reoperation.
Objective To construct a risk prediction model for delayed discharge after R0 resection of colorectal cancer using machine learning algorithms based on preoperative parameters and to compare the predictive performance of different models. Methods Clinical data from 2048 patients with colorectal cancer who underwent R0 resection at Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, from November 2015 to April 2021 were retrospectively analyzed. The data were randomly divided at a 7:3 ratio into a training set (1 433 cases) and a validation set (615 cases). Four algorithms—Logistic regression, support vector machine (SVM), random forest, and extreme gradient boosting (XGBoost)—were used to construct risk prediction models for delayed discharge based on preoperative laboratory parameters and general patient characteristics. Predictive performance was evaluated and compared using the area under the receiver operating characteristic curve (AUC), true-positive rate (TPR), true-negative rate (TNR), accuracy (ACC), and positive predictive value (PPV). Results Postoperative infection was the leading cause of delayed discharge, accounting for 40.52% of all causes of delayed discharge. In the training set, the AUCs of the XGBoost, random forest, SVM, and Logistic regression models were 0.762, 0.772, 0.747, and 0.750, respectively; the corresponding values in the validation set were 0.747, 0.735, 0.729, and 0.738. The XGBoost model had the best overall predictive performance. Its TNR was significantly higher than that of the SVM model (P=0.046), and its TNR (P<0.001) and ACC (P=0.001) were significantly better than those of the Logistic regression model. The top 10 variables contributing to XGBoost predictions, in descending order, were body temperature, carbohydrate antigen 72-4 (CA72-4), hormone therapy, albumin, uric acid (UA), serum sodium (Na), total cholesterol, white blood cell count (WBC), carcinoembryonic antigen (CEA), and neutrophil percentage. Conclusion Among the four models, XGBoost had the best predictive performance. Body temperature, CA72-4, hormone therapy, albumin, and UA were the top 5 preoperative variables contributing to model predictions. The model may facilitate early identification of high-risk patients and inform intervention planning.
Objective To determine whether, beyond the conventional radiotherapy-based time anchor, the interval from the last immunotherapy administration to MRI reassessment also constitutes a key time anchor influencing assessment accuracy in patients with proficient mismatch repair/microsatellite-stable (pMMR/MSS) mid-to-low locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy followed by immunotherapy (inCRT). Methods This retrospective study included 406 patients who underwent radical surgery after neoadjuvant therapy at Peking Union Medical College Hospital between June 2022 and April 2026. The inCRT cohort (n=136) was the primary analysis cohort, and the neoadjuvant chemoradiotherapy (nCRT) cohort (n=270) served as the reference. Pathologic suitability for organ preservation was defined as ypT0-1N0, and MRI suitability as MRI tumor regression grade (mrTRG) 1-2 with no suspicious residual lymph nodes (ymrN0). Concordance between MRI and pathology was considered an accurate assessment and served as the primary endpoint. The MRI reassessment interval was defined as the time from completion of the last relevant antitumor treatment to MRI reassessment; the interval from completion of radiotherapy to MRI was examined in sensitivity analyses. Multivariable Logistic regression and restricted cubic spline (RCS) models were used to evaluate time-effect associations of diagnostic performance. Results In the inCRT cohort, the median age was 60 years (Q1, 52; Q3, 67), 89 patients (65.4%) were male, 29 (21.3%) had baseline mrT4 disease, 83 (61.0%) had mrN2 disease, 63 (46.3%) had mesorectal fascia involvement, and 76 (55.9%) had extramural vascular invasion; 107 patients (78.7%) received long-course radiotherapy. 35 patients (25.7%) met the MRI criteria for suitability for organ preservation, whereas 66 patients (48.5%) met the pathologic criterion. The accuracy, sensitivity, and specificity of MRI assessment were 65.4%, 40.9%, and 88.6%, respectively. The interval from the last immunotherapy administration to MRI was longer in patients with accurate than inaccurate assessments [26 (17, 36) vs. 18 (9.5, 33) days, P=0.017]. Each 7-day increase in the interval was associated with greater odds of an accurate MRI assessment (adjusted OR, 1.273; 95%CI 1.025-1.600; P=0.029). RCS analysis showed a significant overall association between the interval and assessment accuracy (overall P=0.034), without evidence of nonlinearity (P for nonlinearity=0.158). Mean adjusted predicted accuracies during weeks 1-2, 3-4, and 5-6 after the last immunotherapy administration were 50.1%, 69.7%, and 72.6%, respectively. Accuracy during weeks 3-4 was 19.7 percentage points higher than during weeks 1-2 (95%CI 3.0-36.9 percentage points; P=0.046), whereas no further significant improvement was observed during weeks 5-6 (P=1.000). When the interval was anchored to completion of radiotherapy, no significant time-dependent associations were observed for accuracy, sensitivity, or specificity in the inCRT cohort. In the nCRT cohort, the interval was shorter in patients with accurate assessments [15.5 (5, 25) vs. 21 (10, 28.75) days, P=0.018], but neither Logistic regression nor the overall RCS test showed improved diagnostic performance with increasing interval. Conclusion In patients with pMMR/MSS locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy followed by immunotherapy, an appropriate delay in MRI reassessment after the last immunotherapy administration may improve identification of patients pathologically suitable for organ preservation. Reassessment at 3-4 weeks may provide a reasonable balance between assessment reliability and timely subsequent decision-making and warrants further prospective validation.
With the widespread use of metabolic and bariatric surgery (MBS) to treat obesity and related metabolic disorders, postoperative portal venous system thrombosis (PVST), although uncommon, has received increasing clinical attention because it can be life-threatening. Its development is multifactorial and involves obesity-associated hypercoagulability, surgical trauma, pneumoperitoneum-induced changes in portal venous hemodynamics, postoperative hypovolemia, reduced mobility, and underlying inherited or acquired thrombophilic conditions. Clinical manifestations are nonspecific. Persistent or progressive abdominal pain is the most common and important warning symptom but is easily confused with common postoperative gastrointestinal symptoms, anastomosis-related complications, or intestinal obstruction, potentially delaying diagnosis. Portal venous phase contrast-enhanced computed tomography is the principal imaging modality for diagnosing PVST and can determine thrombus location, the extent of venous involvement, and the presence of severe complications such as intestinal ischemia. Laboratory markers, including D-dimer, blood lactate, inflammatory markers, and liver function abnormalities, can assist in early risk identification and disease severity assessment but cannot replace imaging confirmation. Systemic anticoagulation is the cornerstone of treatment. Interventional thrombectomy, catheter-directed thrombolysis, or transjugular intrahepatic portosystemic shunt may be considered for patients with progressive thrombosis, impaired intestinal perfusion, or an inadequate response to anticoagulation. Prompt surgical intervention is warranted when bowel necrosis, peritonitis, or hemodynamic instability occurs. Standardized management of PVST after MBS should encompass risk factor identification, clinical early warning, imaging confirmation, risk-stratified treatment, and perioperative prevention to facilitate early recognition and timely intervention, reduce the risk of missed diagnoses and progression to severe disease, and improve patient outcomes.
Sleeve gastrectomy with transit bipartition (SG-TB) creates a second route for food passage in addition to sleeve gastrectomy, preserving the physiological pyloric-duodenal and part of the proximal intestinal pathway while allowing part of the food stream to reach the distal intestine earlier. With the accumulation of clinical evidence, research has shifted from evaluating overall efficacy to the integrated optimization of sleeve configuration, gastroenteric anastomosis, and intestinal limb length. Standardized construction of a regular, unobstructed, and moderately pressurized sleeve, together with a well-perfused, tension-free, and untwisted gastroenteric anastomosis of an appropriate location and diameter, provides the basis for balancing food diversion and gastric decompression. Progressive common-channel lengthening in classic Roux-en-Y transit bipartition (RYTB), as well as comparisons between single-anastomosis sleeve ileal bypass (SASI) and single-anastomosis sleeve jejunal bypass (SASJ) within one-anastomosis transit bipartition (OATB), indicates that excessive shortening of the effective absorptive bowel may be accompanied by increased risks of malnutrition, diarrhea, and revisional surgery. Sleeve gastrectomy with Braun anastomosis transit bipartition (B-TB), sleeve gastrectomy with duodenal transit bipartition (S-DTB), and magnetic compression anastomosis offer new approaches to regulating bile flow and preserving physiological food passage, although their long-term efficacy and safety remain to be established. Future standardization of SG-TB should move beyond mechanically applying fixed lengths and toward individualized functional reconstruction based on total small bowel length, specific anastomotic configuration, common-channel or effective absorptive bowel length, and actual food-flow volume, with the aim of balancing weight loss and metabolic improvement, reflux control, nutritional safety, and the risk of revisional surgery.
Metabolic and bariatric surgery (MBS) is an important treatment for severe obesity and its metabolic comorbidities. With increasing procedural volume and longer follow-up, long-term complications such as anastomotic stricture and marginal ulcer (MU) have drawn growing attention because of their effects on surgical outcomes and patients’ quality of life. Both complications are driven by multiple factors and require a stratified, stepwise, diagnostic and therapeutic pathway; standardized risk assessment, prevention throughout care, and timely intervention are central to improving their clinical management. Anastomotic stricture is associated with local ischemia, anastomotic tension, subclinical leakage, anastomotic technique, and foreign-body reactions. Prevention and treatment should span the perioperative period, including preoperative smoking cessation and nutritional optimization, preservation of anastomotic blood supply and creation of a tension-free anastomosis, and postoperative dietary progression and symptom monitoring. Endoscopy is the mainstay of diagnosis, and treatment should follow a stepwise pathway from endoscopic balloon dilation, adjunctive incision or injection, and stent placement to surgical revision. MU is associated with acid exposure, mucosal ischemia, gastrogastric fistula, pouch size, anastomotic and suture techniques, smoking, nonsteroidal anti-inflammatory drug use, and diabetes. High-risk patients should undergo targeted screening, receive proton pump inhibitor prophylaxis, and maintain long-term lifestyle interventions. Once MU is diagnosed, management should focus on eliminating risk factors, suppressing acid, and protecting the mucosa; recurrent or refractory cases may require endoscopic suturing, stent coverage, foreign-body removal, or surgical reconstruction. Current evidence is derived mainly from single-center retrospective studies. Standardized definitions of complications, a national registry, and prospective multicenter studies are urgently needed to improve the system of stratified prevention, early recognition, stepwise treatment, and multidisciplinary collaboration.
Gastric signet-ring cell carcinoma (GSRCC) is a poorly cohesive subtype of gastric adenocarcinoma with distinctive morphology and biological behavior. Its proportion has increased in recent years, and it tends to occur at a younger age, is relatively more common in women, and exhibits diffuse infiltration, early metastasis, and treatment resistance. Pure and mixed GSRCC differ in invasiveness, lymph node metastasis, and prognosis. Accurate assessment of the signet-ring cell proportion, molecular features, and immunophenotype therefore facilitates stratified management. Early lesions are easily missed because of subtle mucosal changes, scattered tumor-cell infiltration, and inadequate sampling by routine superficial biopsy; histopathology remains the basis of diagnosis. Multiple deep biopsies, endoscopic ultrasonography, computed tomography, magnetic resonance imaging, and fibroblast activation protein inhibitor positron emission tomography/computed tomography may improve detection of primary lesions and peritoneal or ovarian metastases. Treatment should be individualized according to stage, signet-ring cell component, and molecular biomarkers. Endoscopic resection may be performed for eligible early lesions, whereas radical gastrectomy with D2 lymphadenectomy remains the mainstay for other resectable tumors. Advanced disease requires the integrated use of perioperative chemotherapy, targeted therapy, immunotherapy, and intraperitoneal perfusion therapy. GSRCC is generally less sensitive to conventional chemotherapy. Therapies targeting CLDN18.2 and other molecular targets are promising, but GSRCC-specific evidence remains relatively limited. Future efforts should include strengthening screening of high-risk populations, investigating molecular subtypes, resistance mechanisms, and the immune microenvironment in depth, and improving artificial intelligence-assisted diagnosis and prognostic assessment to advance precision diagnosis and treatment.
Portal vein stenosis (PVS) after pancreatoduodenectomy (PD) may result from anastomotic narrowing, postoperative local inflammation or compression, thrombosis, tumor recurrence, and other factors. Concomitant portal vein resection and reconstruction (PVR), postoperative pancreatic fistula, intra-abdominal infection, and other factors may increase the risk of PVS. Clinical manifestations include abdominal pain, ascites, gastrointestinal bleeding (GIB), and liver dysfunction related to portal hypertension. Management should be individualized according to the cause and severity of stenosis, clinical symptoms, tumor status, and expected benefit. Close surveillance is appropriate for patients with stable asymptomatic stenosis. Anticoagulation, catheter-directed thrombolysis, or mechanical thrombectomy may be considered for patients with predominantly acute thrombotic lesions. Balloon angioplasty may be used in selected patients with focal benign stenosis. Portal vein stenting can rapidly restore portal venous flow and is the main interventional treatment for symptomatic or progressive severe stenosis, whereas surgical re-reconstruction or shunting is reserved for the few patients in whom interventional treatment is not feasible. Available studies have shown high technical success and symptom relief rates after stenting; however, uncertainty remains regarding long-term patency, postoperative antithrombotic therapy, balloon predilation, and the optimal access route. Postoperative follow-up should be individualized using Doppler ultrasonography, contrast-enhanced computed tomography, or magnetic resonance imaging. Current evidence is mainly derived from single-center retrospective studies, and multicenter prospective studies are warranted to further refine the indications and technical standards for intervention.
