Transoral Outlet Reduction for Dumping Syndrome after Roux-En-Y Gastric Bypass: A Systematic Review and Meta-Analysis

Transoral Outlet Reduction for Dumping Syndrome after Roux-En-Y Gastric Bypass: A Systematic Review and Meta-Analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Transoral Outlet Reduction for Dumping Syndrome after Roux-En-Y Gastric Bypass: A Systematic Review and Meta-Analysis Azizullah Beran, Daryl Ramai, Almaza Albakri, Khaled Alchirazi, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7024238/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 27 Sep, 2025 Read the published version in Obesity Surgery → Version 1 posted 11 You are reading this latest preprint version Abstract Introduction: Dumping syndrome is a complication of Roux-en-Y gastric bypass (RYGB) surgery that can significantly affect quality of life. Transoral outlet reduction (TORe) is a minimally invasive endoscopic procedure that reduces the size of the gastrojejunal anastomosis (GJA) through ablation and/or endoscopic suturing, primarily used to address weight regain after RYGB. Emerging evidence highlights the feasibility and safety of TORe as a treatment for medically refractory dumping syndrome. This meta-analysis aims to evaluate the efficacy and safety of TORe for dumping syndrome. Methods A systematic search of PubMed, Embase, and Web of Science was conducted through December 2024. Primary outcomes included clinical success (defined as sustained symptom improvement without requiring repeat TORe or revisional surgery at last follow-up) and the mean difference in pre- and post-procedural Sigstad’s score assessments. Secondary outcomes included rates of post-TORe surgery, repeat TORe, and serious adverse events. Pooled rate estimates and mean differences (MD) with the corresponding 95% confidence intervals (CI) were calculated using random-effects models. Results Six studies with 333 post-RYGB patients with dumping syndrome were included. The pooled clinical success of TORe was 83% (95% CI 71%-90%, I 2 = 74%). Furthermore, TORe resulted in a significant improvement in Sigstad’s score (MD − 11.12 [95% CI -15.33 to − 6.91], P < 0.001, I 2 = 89%). The rate of serious adverse events was 3% (95% CI 0.7%-12.4%, I 2 = 68%). Conclusions Our findings suggest that TORe is a safe and effective minimally invasive treatment for patients with medically refractory dumping syndrome. Further prospective studies with longer follow-up durations are warranted to validate these findings. transoral outlet reduction gastrojejunal anastomosis revision Roux-en-Y gastric bypass dumping syndrome Figures Figure 1 Figure 2 Figure 3 INTRODUCTION Obesity is a chronic, relapsing disease that has reached pandemic levels worldwide[ 1 ]. In response, a growing number of individuals are turning to bariatric surgery, which is the most effective long-term intervention for sustained weight loss and improvement in obesity-related comorbidities[ 2 ]. Roux-en-Y gastric bypass (RYGB) remains one of the most widely performed and well-established bariatric surgeries for weight loss[ 3 ]. However, despite its durable efficacy, RYGB is associated with adverse events such as marginal ulcer, weight regain and dumping syndrome[ 4 , 5 ]. Dumping syndrome, a frequent but underdiagnosed complication of RYGB, affects up to 25–50% of patients and can significantly reduce health-related quality of life[ 6 – 8 ]. This condition is characterized by recurrent episodes of postprandial hypoglycemia, presenting with a constellation of gastrointestinal symptoms (abdominal pain, bloating, borborygmi, nausea and diarrhea) and vasomotor symptoms (flushing, palpitations, perspiration, tachycardia, hypotension, fatigue, rarely, syncope)[ 9 ]. Dumping syndrome is classified into two types: early dumping syndrome, which typically occurs within one hour after eating and is believed to result from rapid fluid shifts, and late dumping syndrome, which manifests 1–3 hours post-meal and is thought to stem from an incretin-driven hyperinsulinemia after carbohydrate ingestion[ 9 ]. The Sigstad scoring system is typically used to assess the severity of dumping syndrome[ 10 ]. Dietary modifications are the mainstay treatment for dumping syndrome, which includes small frequent meals and avoiding simple carbohydrates[ 9 ]. Medications such as acarbose can be used as second line when dietary modifications are insufficient[ 9 ]. In refractory cases, surgical revisional procedures may be considered; however, these can be technically difficult in the presence of altered anatomy and adhesions and are associated with an increased risk of complications[ 9 , 11 ]. Transoral outlet reduction (TORe) is a minimally invasive endoscopic procedure that reduces the size of the post-RYGB gastrojejunal anastomosis (GJA) through ablation and/or endoscopic suturing, primarily used to address weight regain after RYGB[ 12 ]. Emerging evidence highlights the feasibility and safety of TORe as a treatment for dumping syndrome that is refractory to dietary modifications and medical therapy[ 13 ]. This systematic review and meta-analysis aims to evaluate the efficacy and safety of TORe for managing dumping syndrome. METHODS Data Sources and Search Strategy We conducted a comprehensive search of PubMed, Embase, and Web of Science databases from inception through December 31st, 2024 for published studies that assess the efficacy and safety of TORe for management of dumping syndrome. We also manually identified additional relevant studies using the references of included studies. The following MeSH terms were used: (“transoral outlet reduction”) and (“dumping syndrome”). Supplementary Table 1 describes the full search terms used in each database searched. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to select the final studies[ 14 ]. No Institutional Review Board or Ethics Committee approval required for this study. Two reviewers (AB and AA) independently screened and selected the potentially included studies. Discrepancies were addressed by a third reviewer (DR). Eligibility Criteria All peer-reviewed studies (observational studies or randomized controlled trials) that assessed the efficacy and safety outcomes of TORe procedure for managing dumping syndrome following RYGB were eligible for inclusion. Case reports, case series, and conference abstracts were excluded. Data Extraction Data on study and patient characteristics and outcome measures were extracted by two independent reviewers (AB and AA). Extracted study characteristics included country of origin, study period and design, sample size, female gender percentage, age, baseline body mass index (BMI), GJA size (pre- and post-TORe), device type, procedure duration, number of sutures, pattern of suturing, follow-up period, proportion of weekend admissions, and reported outcomes (clinical success, pre- and post-TORe Sigstad’s score, need for surgical intervention, need for repeat TORe, and serious adverse events). Outcomes and Definitions The primary outcomes were clinical success and the mean difference in pre- and post-procedural Sigstad’s score assessments. Clinical success was defined as sustained symptom improvement without the need for repeat TORe or revisional surgery at the final follow-up. Secondary outcomes included rates of surgery and repeat TORe to address refractory symptoms, and post-procedural serious adverse events. Statistical Analysis Pooled rate estimates and mean differences (MD) with the corresponding 95% confidence intervals (CI) were calculated using random-effects models. P-values < 0.05 were considered statistically significant. Statistical heterogeneity was evaluated using the I 2 statistics and I 2 value of ≥ 50% was considered significant heterogeneity. All statistical analyses were conducted via Comprehensive Meta-Analysis version 4. To further validate the robustness of our results, we conducted a leave-one-out sensitivity analysis for clinical success. Bias Assessment Risk of bias was assessed using the Newcastle-Ottawa Assessment Scale for included studies[ 15 ]. Two authors (AB and DR) independently assessed each study for bias. Discrepancies were resolved by consensus. Publication bias was assessed qualitatively by visually assessing the funnel plot and quantitively using Egger’s regression analysis for clinical success. RESULTS Study Selection Of the 101 studies initially screened, 10 met the inclusion criteria for this systematic review. However, four of these were excluded—three were conference abstracts, and one evaluated outcomes of a procedure other than TORe. Consequently, six [ 13 , 16 – 20 ] were included in the final meta-analysis. A visual summary of the selection process is provided in Fig. 1 . Study and Patient Characteristics Study and patient characteristics are summarized in Table 1 . All studies were published between 2020 and 2024. Geographically, two[ 13 , 18 ] studies were conducted in Switzerland, one[ 17 ] in Israel, one[ 16 ] in Italy, one[ 20 ] in United States, and one[ 19 ] was a multinational study involving the United States and Germany. In terms of study design, five[ 13 , 16 – 18 , 20 ] studies were retrospective cohort studies while one[ 19 ] was a prospective study. A total of 333 post-RYGB patients with dumping syndrome who underwent TORe were included in the six included studies[ 13 , 16 – 20 ]. Table 1 Baseline characteristics and outcomes of the studies included in the meta-analysis. Lovis, 2024 Petchers, 2022 Pontecorvi, 2023 Relly, 2021 Tsai, 2020 Vargas, 2020 Country of origin Switzerland United States Italy Israel Switzerland United States and Germany Study design Retrospective cohort Retrospective cohort Retrospective cohort Retrospective cohort Retrospective cohort Prospective cohort Study period January 2015 - December 2020 January 2013 - December 2018 January 2015 - June 2021 August 2018 - September 2019 January 2016 - August 2018 2014–2018 Total number of patients 9 98 58 13 40 115 Female gender, n (%) 8 (88.9%) 96 (98%) NR 10 (76.9%) 27 (67.5%) 97 (84.3%) Age, years, mean (range) or mean ± SD 46.0 (IQR 39.5)* 51 ± 9.9 NR 45.1 (25–56) 47.1 (22-75.4) 44.9 ± 9.2 Baseline BMI (kg/m²) or weight (kg), mean (range) or mean ± SD 34.5 (IQR 30.6–38.2)* 36.15 ± 7.1 NR 33.5 (28.1–40.3) 44.5 (35–60) 98.4 ± 22.7 Pre-TORe GJA size, mm, mean (range) or mean ± SD 30 (IQR 25–30)* NR NR 25.2 (15–30) 22.6 (18–35) 39.8 ± 6.7 Post-TORe GJA size, mm, mean (range) 9.5 (IQR 9.5–10)* NR NR 5.6 (5–10) 6.2 (4–13) 8–10 Device type OverStitch (Apollo) OverStitch (Apollo) OverStitch (Apollo) OverStitch (Apollo) OverStitch (Apollo) OverStitch (Apollo) Procedure duration, minutes, mean (range) 30 (IQR 25–43)* 73 ± 27 (n = 59) NR 47 (29–66) 18.5 (12–41) 38.9 ± 17.3 Number of sutures 3 (IQR 2–3)* NR 2–3 sutures per patient 2 sutures 1* (range 1–3) Mean 3 (range 2–5) Pattern of suturing Simple interrupted Figure of 8 Simple interrupted Figure of 8 NR Simple interrupted or figure of 8 Follow-up period 12 months 3.45 years ± 1.7 6 months 6 months Mean 12.5 months (range 1-33.8) 3 months Clinical success, n (%) 7 (77.8%) 65/77 (84%) 40 (69%) 11 (84.6%) 30 (75%) 109 (94.8%) Pre-TORe Sigstad’s score, mean ± SD NR NR 15 (11-18.5)* 19.4 ± 3.6 13.9 (range 0–28) (n = 25) 17.02 ± 6.1 Post-TORe Sigstad’s score, mean ± SD NR NR 3 (1-9.5)* 5.2 ± 5.5 8.6 (range 0–28) (n = 25) 2.55 ± 1.87 Surgical intervention, n (%) 2 (22.2%) NR NR None 2 (5%) 3 (2.6%) Repeat TORe, n (%) None NR None 2 (15.4%) 9 (22.5%) 3 (2.6%) Serious adverse events, n (%) 1 (11%) (stenosis) 1 (1%) (bleeding) 1 (1.7%) (abscess) 3 (23.1%) (nausea and vomiting requiring overnight hospitalization) None None *Median Abbreviations: BMI: body mass index, GJA: gastrojejunal anastomosis, n: sample size, NR: not reported, SD: standard deviation, TORe: transoral outlet reduction. Among the five[16-20] studies that reported demographic and procedural details (n=275 patients), 87% of patients were female, with a mean age of 47.5±11.2 years and a mean BMI of 42.2±10.3 kg/m². Among the four[13, 17-19] studies reporting these data, the baseline mean diameter of the GJA was 34.2 ± 9.8 mm, and the mean baseline Sigstad score was 16.2 ± 7.4. All TORe procedures utilized the OverStitch (Apollo) device for endoscopic suturing. The mean procedure duration, reported across five[13, 17-20] studies, was 45.3±27.4 minutes. In the small subset of patients with available data (n=62), the mean post-procedural GJA diameter was reduced to 6.6 ± 4.01 mm. Follow-up durations across the studies ranged from 3 months to 3.4 years. Primary Outcomes: Clinical Success and Improvement in Sigstad’s Score All[13, 16-20] studies (n=312 patients, 21 patients lost to follow up) reported clinical success. The overall pooled clinical success was 83% (95% CI 71%-90%, I 2 =74%, Figure 2A). A Leave-one-out sensitivity analysis for clinical success showed consistent results (Supplementary Figure 1). Four[16-19] studies (n=211 patients) reported pre-TORe and post-TORe Sigstad’s score. TORe resulted in a significant improvement in Sigstad’s score (MD −11.12 [95% CI -15.33 to −6.91], P<0.001, I 2 =89%, Figure 2B). Secondary Outcomes: Rates of Surgery and Repeat TORe, and Serious Adverse Events Four[13, 17-19] studies (n=177 patients) reported the rate of surgery post-TORe. The pooled rate of surgery post-TORe was 5.8% (95% CI 25-15.8%, I 2 =48%, Figure 3A). All[13, 16-19] studies (n=235 patients) reported the rate of repeat TORe. The pooled rate of repeat TORe was 6.9% (95% CI 1.9%-22%, I 2 =75%, Figure 3B). ). A Leave-one-out sensitivity analysis for repeat TORe showed consistent results (Supplementary Figure 2). All[13, 16-20] studies (n=333) reported the rate of serious adverse events. The pooled overall rate of serious adverse events was 3% (95% CI 0.7%-12.4%, I 2 =68%, Figure 3C). Table 1 shows the details of serious adverse events reported in each study. Bias Assessment The risk of bias was assessed and summarized in Supplementary Table 2. Of the six included studies, four[11, 12, 19, 21] were of low risk of bias while two[13, 20] was of high risk of bias in the assessment of outcomes. We found no evidence of publication bias for clinical success (p=0.59) (Supplementary Figure 3). DISCUSSION This systematic review and meta-analysis demonstrates that transoral outlet reduction (TORe) is a safe and effective minimally invasive therapeutic option for managing dumping syndrome. The pooled clinical success rate of TORe in treating refractory dumping syndrome was 83%, while the overall rate of serious adverse events remained low at 3%. These findings support the use of TORe as a valid intervention for patients with dumping syndrome who do not respond to lifestyle modifications and medical therapy, offering a less invasive alternative to surgical revision. TORe was initially developed to induce weight loss by reducing the diameter of the GJA, thereby slowing gastric emptying and addressing the issue of a dilated, incompetent anastomosis[21]. Since rapid gastric emptying drives the symptoms of early and late dumping syndrome, TORe’s ability to enhance tissue competence and reduce GJA diameter, thereby delaying gastric pouch content release, accounts for its high clinical success rate and significant reduction in Sigstad scores[22]. In our meta-analysis, post-TORe Sigstad scores were significantly reduced compared to baseline, with a pooled mean 11.1-point reduction (p<0.001). Most studies in this meta-analysis employed simple interrupted or figure-of-eight suturing patterns. While the purse-string technique has demonstrated superior weight loss outcomes compared to interrupted suturing[23], its impact on dumping syndrome efficacy remains unexplored. Future research comparing suturing techniques could clarify their relative effectiveness in this context. Our updated meta-analysis builds upon the 2021 meta-analysis by Bazarbashi et al.[24], which had notable limitations, including the incorporation of conference abstracts. In contrast, our study employed rigorous selection criteria, including only peer-reviewed studies to better evaluate bias risks and achieve more accurate effect estimates. We also incorporated newer studies not present in the prior analysis[13, 16, 20, 24]. Unlike Bazarbashi et al.[24], we assessed the efficacy of TORe for dumping syndrome using objective Sigstad scoring system criteria, demonstrating a significant improvement in Sigstad scores by the endoscopic intervention. Despite the encouraging results, several limitations should be acknowledged. First, the analysis is based exclusively on observational studies, with no randomized controlled trials (RCTs) available to date. This reliance on non-randomized data introduces potential risks of unmeasured confounding and selection bias. Consequently, high-quality prospective series and RCTs would confirm and strengthen the current evidence base. Second, although a random-effects model was employed to account for inter-study variability, significant statistical heterogeneity was observed across many outcomes. This may be attributable to differences in patient characteristics, baseline severity of dumping syndrome, definitions of clinical success, and variability in follow-up durations. Third, the follow-up periods reported in the majority of the included studies were relatively short, limiting the ability to assess long-term durability and outcomes of TORe. Lastly, not all studies provided objective, quantitative pre- and post-procedure assessments using the Sigstad scoring system, which limits the ability to uniformly evaluate treatment response across cohorts. Nevertheless, this study has important strengths. To our knowledge, it represents the first meta-analysis to evaluate the efficacy of TORe for dumping syndrome using objective criteria based on Sigstad’s scoring system. By synthesizing available data from multiple international cohorts, this analysis provides valuable insight into the clinical utility of TORe in this challenging patient population. In conclusion, our findings suggest that TORe is a safe and effective minimally invasive treatment for patients with medically refractory dumping syndrome. TORe should be considered before proceeding to surgical revision, which carries higher morbidity and technical complexity. Further prospective studies, particularly randomized trials with longer follow-up durations, are warranted to validate these findings. Declarations Author Contribution Contributions: Conceptualization and design: AB and MG. Manuscript drafting: AB, AA, DR, KE, and MG. Data collection: AB, AA, and FE. Statistical analysis: AB. Tables: AB, DR, AA. Critical revision of manuscript: MG and NS. Guarantor of article: MG. Final review and approval of the manuscript: All authors.No IRB or Ethics Committee required for this study. References Flegal, K.M., et al., Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999-2010. Jama, 2012. 307 (5): p. 491-7. Mingrone, G., et al., Bariatric-metabolic surgery versus conventional medical treatment in obese patients with type 2 diabetes: 5 year follow-up of an open-label, single-centre, randomised controlled trial. Lancet, 2015. 386 (9997): p. 964-73. English, W.J., et al., American Society for Metabolic and Bariatric Surgery estimation of metabolic and bariatric procedures performed in the United States in 2016. Surg Obes Relat Dis, 2018. 14 (3): p. 259-263. Beran, A., et al., Predictors of marginal ulcer after gastric bypass: a systematic review and meta-analysis. J Gastrointest Surg, 2023. 27 (6): p. 1066-1077. Cooper, T.C., et al., Trends in Weight Regain Following Roux-en-Y Gastric Bypass (RYGB) Bariatric Surgery. Obes Surg, 2015. 25 (8): p. 1474-81. Berg, P. and R. McCallum, Dumping Syndrome: A Review of the Current Concepts of Pathophysiology, Diagnosis, and Treatment. Dig Dis Sci, 2016. 61 (1): p. 11-8. Emous, M., et al., The short- to mid-term symptom prevalence of dumping syndrome after primary gastric-bypass surgery and its impact on health-related quality of life. Surg Obes Relat Dis, 2017. 13 (9): p. 1489-1500. van Beek, A.P., et al., Dumping syndrome after esophageal, gastric or bariatric surgery: pathophysiology, diagnosis, and management. Obes Rev, 2017. 18 (1): p. 68-85. Scarpellini, E., et al., International consensus on the diagnosis and management of dumping syndrome. Nat Rev Endocrinol, 2020. 16 (8): p. 448-466. Sigstad, H., A clinical diagnostic index in the diagnosis of the dumping syndrome. Changes in plasma volume and blood sugar after a test meal. Acta Med Scand, 1970. 188 (6): p. 479-86. Dolan, R.D., P. Jirapinyo, and C.C. Thompson, Endoscopic versus surgical gastrojejunal revision for weight regain in Roux-en-Y gastric bypass patients: 5-year safety and efficacy comparison. Gastrointestinal Endoscopy, 2021. 94 (5): p. 945-950. Jirapinyo, P., et al., Five-year outcomes of transoral outlet reduction for the treatment of weight regain after Roux-en-Y gastric bypass. Gastrointest Endosc, 2020. 91 (5): p. 1067-1073. Lovis, J., et al., Long-term results after transoral outlet reduction (TORe) of the gastrojejunal anastomosis for secondary weight regain and dumping syndrome after Roux-en-Y gastric bypass. Surg Endosc, 2024. 38 (8): p. 4496-4504. Page, M.J., et al., The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. Bmj, 2021. 372 : p. n71. Stang, A., Critical evaluation of the Newcastle-Ottawa scale for the assessment of the quality of nonrandomized studies in meta-analyses. Eur J Epidemiol, 2010. 25 (9): p. 603-5. Pontecorvi, V., et al., Long-term Outcomes of Transoral Outlet Reduction (TORe) for Dumping Syndrome and Weight Regain After Roux-en-Y Gastric Bypass. Obes Surg, 2023. 33 (4): p. 1032-1039. Relly, R., et al., Endoscopic trans-oral outlet reduction after bariatric surgery is safe and effective for dumping syndrome. Surg Endosc, 2021. 35 (12): p. 6846-6852. Tsai, C., et al., Short-term outcomes of endoscopic gastro-jejunal revisions for treatment of dumping syndrome after Roux-En-Y gastric bypass. Surg Endosc, 2020. 34 (8): p. 3626-3632. Vargas, E.J., et al., Endoscopic management of dumping syndrome after Roux-en-Y gastric bypass: a large international series and proposed management strategy. Gastrointest Endosc, 2020. 92 (1): p. 91-96. Petchers, A., et al., Evaluation of endoscopic gastrojejunostomy revision after Roux-en-Y gastric bypass for treatment of dumping syndrome. Gastrointest Endosc, 2022. 96 (4): p. 639-644. Thompson, C.C., et al., Endoscopic suturing for transoral outlet reduction increases weight loss after Roux-en-Y gastric bypass surgery. Gastroenterology, 2013. 145 (1): p. 129-137.e3. Tack, J., et al., Pathophysiology, diagnosis and management of postoperative dumping syndrome. Nat Rev Gastroenterol Hepatol, 2009. 6 (10): p. 583-90. Schulman, A.R., N. Kumar, and C.C. Thompson, Transoral outlet reduction: a comparison of purse-string with interrupted stitch technique. Gastrointest Endosc, 2018. 87 (5): p. 1222-1228. Bazarbashi, A.N., et al., Endoscopic revision of gastrojejunal anastomosis for the treatment of dumping syndrome in patients with Roux-en-Y gastric bypass: a systematic review and meta-analysis. Surg Endosc, 2022. 36 (6): p. 4099-4107. Additional Declarations No competing interests reported. Supplementary Files SupplementaryMaterialUPDATED.docx Cite Share Download PDF Status: Published Journal Publication published 27 Sep, 2025 Read the published version in Obesity Surgery → Version 1 posted Editorial decision: Revision requested 30 Jul, 2025 Reviews received at journal 30 Jul, 2025 Reviews received at journal 28 Jul, 2025 Reviews received at journal 28 Jul, 2025 Reviewers agreed at journal 20 Jul, 2025 Reviewers agreed at journal 18 Jul, 2025 Reviewers agreed at journal 17 Jul, 2025 Reviewers invited by journal 17 Jul, 2025 Editor assigned by journal 08 Jul, 2025 Submission checks completed at journal 07 Jul, 2025 First submitted to journal 01 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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studies.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7024238/v1/77a56bd3a320b6bd2841f944.png"},{"id":87379907,"identity":"7b670792-ea03-41df-ba6e-df82f1d7e230","added_by":"auto","created_at":"2025-07-23 08:31:50","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":273000,"visible":true,"origin":"","legend":"\u003cp\u003eForest plots for (A) clinical success of TORe for managing dumping syndrome and (B) pre- and post-TORe Sigstad score improvement.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7024238/v1/9d3abde2abd5d015bce45a83.png"},{"id":87382910,"identity":"a2c9739f-15df-4a1a-b158-e0d12ba27b31","added_by":"auto","created_at":"2025-07-23 08:39:50","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1180902,"visible":true,"origin":"","legend":"\u003cp\u003eForest plots for (A) surgery post-TORe, (B) repeat TORe, and (C) serious adverse events.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7024238/v1/3b323140a87206ba7af8816c.jpeg"},{"id":92430921,"identity":"373ad37f-5e00-41e5-8faf-e1bd24c1d8ff","added_by":"auto","created_at":"2025-09-29 16:08:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2158965,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7024238/v1/1d25039b-2b83-4b51-9fff-2f5f53133f70.pdf"},{"id":87379896,"identity":"5a5770f9-6af2-4863-947d-48c559e7ac87","added_by":"auto","created_at":"2025-07-23 08:31:50","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":59694,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterialUPDATED.docx","url":"https://assets-eu.researchsquare.com/files/rs-7024238/v1/033976bd11173802df39bd34.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Transoral Outlet Reduction for Dumping Syndrome after Roux-En-Y Gastric Bypass: A Systematic Review and Meta-Analysis","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eObesity is a chronic, relapsing disease that has reached pandemic levels worldwide[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. In response, a growing number of individuals are turning to bariatric surgery, which is the most effective long-term intervention for sustained weight loss and improvement in obesity-related comorbidities[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Roux-en-Y gastric bypass (RYGB) remains one of the most widely performed and well-established bariatric surgeries for weight loss[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, despite its durable efficacy, RYGB is associated with adverse events such as marginal ulcer, weight regain and dumping syndrome[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDumping syndrome, a frequent but underdiagnosed complication of RYGB, affects up to 25–50% of patients and can significantly reduce health-related quality of life[\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e–\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. This condition is characterized by recurrent episodes of postprandial hypoglycemia, presenting with a constellation of gastrointestinal symptoms (abdominal pain, bloating, borborygmi, nausea and diarrhea) and vasomotor symptoms (flushing, palpitations, perspiration, tachycardia, hypotension, fatigue, rarely, syncope)[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Dumping syndrome is classified into two types: early dumping syndrome, which typically occurs within one hour after eating and is believed to result from rapid fluid shifts, and late dumping syndrome, which manifests 1–3 hours post-meal and is thought to stem from an incretin-driven hyperinsulinemia after carbohydrate ingestion[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The Sigstad scoring system is typically used to assess the severity of dumping syndrome[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDietary modifications are the mainstay treatment for dumping syndrome, which includes small frequent meals and avoiding simple carbohydrates[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Medications such as acarbose can be used as second line when dietary modifications are insufficient[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In refractory cases, surgical revisional procedures may be considered; however, these can be technically difficult in the presence of altered anatomy and adhesions and are associated with an increased risk of complications[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Transoral outlet reduction (TORe) is a minimally invasive endoscopic procedure that reduces the size of the post-RYGB gastrojejunal anastomosis (GJA) through ablation and/or endoscopic suturing, primarily used to address weight regain after RYGB[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Emerging evidence highlights the feasibility and safety of TORe as a treatment for dumping syndrome that is refractory to dietary modifications and medical therapy[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This systematic review and meta-analysis aims to evaluate the efficacy and safety of TORe for managing dumping syndrome.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003e\u003cb\u003eData Sources and Search Strategy\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWe conducted a comprehensive search of PubMed, Embase, and Web of Science databases from inception through December 31st, 2024 for published studies that assess the efficacy and safety of TORe for management of dumping syndrome. We also manually identified additional relevant studies using the references of included studies. The following MeSH terms were used: (“transoral outlet reduction”) and (“dumping syndrome”). Supplementary Table\u0026nbsp;1 describes the full search terms used in each database searched. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to select the final studies[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. No Institutional Review Board or Ethics Committee approval required for this study. Two reviewers (AB and AA) independently screened and selected the potentially included studies. Discrepancies were addressed by a third reviewer (DR).\u003c/p\u003e\u003cp\u003e\u003cb\u003eEligibility Criteria\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAll peer-reviewed studies (observational studies or randomized controlled trials) that assessed the efficacy and safety outcomes of TORe procedure for managing dumping syndrome following RYGB were eligible for inclusion. Case reports, case series, and conference abstracts were excluded.\u003c/p\u003e\u003cp\u003e\u003cb\u003eData Extraction\u003c/b\u003e\u003c/p\u003e\u003cp\u003e Data on study and patient characteristics and outcome measures were extracted by two independent reviewers (AB and AA). Extracted study characteristics included country of origin, study period and design, sample size, female gender percentage, age, baseline body mass index (BMI), GJA size (pre- and post-TORe), device type, procedure duration, number of sutures, pattern of suturing, follow-up period, proportion of weekend admissions, and reported outcomes (clinical success, pre- and post-TORe Sigstad’s score, need for surgical intervention, need for repeat TORe, and serious adverse events).\u003c/p\u003e\u003cp\u003e\u003cb\u003eOutcomes and Definitions\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe primary outcomes were clinical success and the mean difference in pre- and post-procedural Sigstad’s score assessments. Clinical success was defined as sustained symptom improvement without the need for repeat TORe or revisional surgery at the final follow-up. Secondary outcomes included rates of surgery and repeat TORe to address refractory symptoms, and post-procedural serious adverse events.\u003c/p\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003ePooled rate estimates and mean differences (MD) with the corresponding 95% confidence intervals (CI) were calculated using random-effects models. P-values \u0026lt; 0.05 were considered statistically significant. Statistical heterogeneity was evaluated using the I\u003csup\u003e2\u003c/sup\u003e statistics and I\u003csup\u003e2\u003c/sup\u003e value of ≥ 50% was considered significant heterogeneity. All statistical analyses were conducted via Comprehensive Meta-Analysis version 4. To further validate the robustness of our results, we conducted a leave-one-out sensitivity analysis for clinical success.\u003c/p\u003e\u003cp\u003e\u003cb\u003eBias Assessment\u003c/b\u003e\u003c/p\u003e\u003cp\u003eRisk of bias was assessed using the Newcastle-Ottawa Assessment Scale for included studies[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Two authors (AB and DR) independently assessed each study for bias. Discrepancies were resolved by consensus. Publication bias was assessed qualitatively by visually assessing the funnel plot and quantitively using Egger’s regression analysis for clinical success.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003e\u003cb\u003eStudy Selection\u003c/b\u003e\u003c/p\u003e\u003cp\u003eOf the 101 studies initially screened, 10 met the inclusion criteria for this systematic review. However, four of these were excluded\u0026mdash;three were conference abstracts, and one evaluated outcomes of a procedure other than TORe. Consequently, six [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR17 CR18 CR19\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] were included in the final meta-analysis. A visual summary of the selection process is provided in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eStudy and Patient Characteristics\u003c/b\u003e\u003c/p\u003e\u003cp\u003eStudy and patient characteristics are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. All studies were published between 2020 and 2024. Geographically, two[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] studies were conducted in Switzerland, one[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] in Israel, one[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] in Italy, one[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] in United States, and one[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] was a multinational study involving the United States and Germany. In terms of study design, five[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] studies were retrospective cohort studies while one[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] was a prospective study. A total of 333 post-RYGB patients with dumping syndrome who underwent TORe were included in the six included studies[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR17 CR18 CR19\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eBaseline characteristics and outcomes of the studies included in the meta-analysis.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLovis, 2024\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePetchers, 2022\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePontecorvi, 2023\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eRelly, 2021\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eTsai, 2020\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eVargas, 2020\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCountry of origin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSwitzerland\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eUnited States\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eItaly\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eIsrael\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eSwitzerland\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eUnited States and Germany\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStudy design\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRetrospective cohort\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRetrospective cohort\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRetrospective cohort\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eRetrospective cohort\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eRetrospective cohort\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eProspective cohort\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStudy period\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eJanuary 2015 - December 2020\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eJanuary 2013 - December 2018\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eJanuary 2015 - June 2021\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAugust 2018 - September 2019\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eJanuary 2016 - August 2018\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2014\u0026ndash;2018\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTotal number of patients\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e115\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFemale gender, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8 (88.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e96 (98%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10 (76.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e27 (67.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e97 (84.3%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge, years, mean (range) or mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e46.0 (IQR 39.5)*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e51\u0026thinsp;\u0026plusmn;\u0026thinsp;9.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e45.1 (25\u0026ndash;56)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e47.1 (22-75.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e44.9\u0026thinsp;\u0026plusmn;\u0026thinsp;9.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBaseline BMI (kg/m\u0026sup2;) or weight (kg), mean (range) or mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e34.5 (IQR 30.6\u0026ndash;38.2)*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e36.15\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e33.5 (28.1\u0026ndash;40.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e44.5 (35\u0026ndash;60)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e98.4\u0026thinsp;\u0026plusmn;\u0026thinsp;22.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePre-TORe GJA size, mm, mean (range) or mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30 (IQR 25\u0026ndash;30)*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e25.2 (15\u0026ndash;30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e22.6 (18\u0026ndash;35)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e39.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePost-TORe GJA size, mm, mean (range)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9.5 (IQR 9.5\u0026ndash;10)*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5.6 (5\u0026ndash;10)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.2 (4\u0026ndash;13)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e8\u0026ndash;10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDevice type\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOverStitch (Apollo)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eOverStitch (Apollo)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOverStitch (Apollo)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eOverStitch (Apollo)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eOverStitch (Apollo)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eOverStitch (Apollo)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eProcedure duration, minutes, mean (range)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30 (IQR 25\u0026ndash;43)*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e73\u0026thinsp;\u0026plusmn;\u0026thinsp;27 (n\u0026thinsp;=\u0026thinsp;59)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e47 (29\u0026ndash;66)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e18.5 (12\u0026ndash;41)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e38.9\u0026thinsp;\u0026plusmn;\u0026thinsp;17.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of sutures\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (IQR 2\u0026ndash;3)*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2\u0026ndash;3 sutures per patient\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2 sutures\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1* (range 1\u0026ndash;3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eMean 3 (range 2\u0026ndash;5)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePattern of suturing\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSimple interrupted\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFigure of 8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSimple interrupted\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFigure of 8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSimple interrupted or\u003c/p\u003e\u003cp\u003efigure of 8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFollow-up period\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12 months\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.45 years\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6 months\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6 months\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMean 12.5 months (range 1-33.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3 months\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eClinical success, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7 (77.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e65/77 (84%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e40 (69%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e11 (84.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e30 (75%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e109 (94.8%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePre-TORe Sigstad\u0026rsquo;s score, mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15 (11-18.5)*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e19.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e13.9 (range 0\u0026ndash;28) (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e17.02\u0026thinsp;\u0026plusmn;\u0026thinsp;6.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePost-TORe Sigstad\u0026rsquo;s score, mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3 (1-9.5)*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5.2\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e8.6 (range 0\u0026ndash;28) (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.55\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSurgical intervention, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (22.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2 (5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3 (2.6%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRepeat TORe, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2 (15.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9 (22.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3 (2.6%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSerious adverse events, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 (11%) (stenosis)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1 (1%) (bleeding)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (1.7%) (abscess)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3 (23.1%) (nausea and vomiting requiring overnight hospitalization)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"7\"\u003e*Median\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAbbreviations: BMI: body mass index, GJA: gastrojejunal anastomosis, n: sample size, NR: not reported, SD: standard deviation, TORe: transoral outlet reduction.\u003c/p\u003e\n\u003cp\u003eAmong the five[16-20] studies that reported demographic and procedural details (n=275 patients), 87% of patients were female, with a mean age of 47.5\u0026plusmn;11.2 years and a mean BMI of 42.2\u0026plusmn;10.3 kg/m\u0026sup2;. Among the four[13, 17-19] studies reporting these data, the baseline mean diameter of the GJA was 34.2 \u0026plusmn; 9.8 mm, and the mean baseline Sigstad score was 16.2 \u0026plusmn; 7.4. All TORe procedures utilized the OverStitch (Apollo) device for endoscopic suturing. The mean procedure duration, reported across five[13, 17-20] studies, was 45.3\u0026plusmn;27.4 minutes. In the small subset of patients with available data (n=62), the mean post-procedural GJA diameter was reduced to 6.6 \u0026plusmn; 4.01 mm. Follow-up durations across the studies ranged from 3 months to 3.4 years.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePrimary Outcomes: Clinical Success and Improvement in Sigstad\u0026rsquo;s Score\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll[13, 16-20] studies (n=312 patients, 21 patients lost to follow up) reported clinical success. The overall pooled clinical success was 83% (95% CI 71%-90%, I\u003csup\u003e2\u003c/sup\u003e=74%, Figure 2A). A Leave-one-out sensitivity analysis for clinical success showed consistent results (Supplementary Figure 1). Four[16-19] studies (n=211 patients) reported pre-TORe and post-TORe Sigstad\u0026rsquo;s score. TORe resulted in a significant improvement in Sigstad\u0026rsquo;s score (MD \u0026minus;11.12 [95% CI -15.33 to \u0026minus;6.91], P\u0026lt;0.001, I\u003csup\u003e2\u003c/sup\u003e=89%, Figure 2B).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSecondary Outcomes: Rates of Surgery and Repeat TORe, and Serious Adverse Events\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFour[13, 17-19] studies (n=177 patients) reported the rate of surgery post-TORe. The pooled rate of surgery post-TORe was 5.8% (95% CI 25-15.8%, I\u003csup\u003e2\u003c/sup\u003e=48%, Figure 3A). All[13, 16-19] studies (n=235 patients) reported the rate of repeat TORe. The pooled rate of repeat TORe was 6.9% (95% CI 1.9%-22%, I\u003csup\u003e2\u003c/sup\u003e=75%, Figure 3B). ). A Leave-one-out sensitivity analysis for repeat TORe showed consistent results (Supplementary Figure 2). All[13, 16-20] studies (n=333) reported the rate of serious adverse events. The pooled overall rate of serious adverse events was 3% (95% CI 0.7%-12.4%, I\u003csup\u003e2\u003c/sup\u003e=68%, Figure 3C). Table 1 shows the details of serious adverse events reported in each study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eBias Assessment\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe risk of bias was assessed and summarized in Supplementary Table 2. Of the six included studies, four[11, 12, 19, 21] were of low risk of bias while two[13, 20] was of high risk of bias in the assessment of outcomes. We found no evidence of publication bias for clinical success (p=0.59) (Supplementary Figure 3).\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis systematic review and meta-analysis demonstrates that transoral outlet reduction (TORe) is a safe and effective minimally invasive therapeutic option for managing dumping syndrome. The pooled clinical success rate of TORe in treating refractory dumping syndrome was 83%, while the overall rate of serious adverse events remained low at 3%. These findings support the use of TORe as a valid intervention for patients with dumping syndrome who do not respond to lifestyle modifications and medical therapy, offering a less invasive alternative to surgical revision.\u003c/p\u003e\n\u003cp\u003eTORe was initially developed to induce weight loss by reducing the diameter of the GJA, thereby slowing gastric emptying and addressing the issue of a dilated, incompetent anastomosis[21]. Since rapid gastric emptying drives the symptoms of early and late dumping syndrome, TORe’s ability to enhance tissue competence and reduce GJA diameter, thereby delaying gastric pouch content release, accounts for its high clinical success rate and significant reduction in Sigstad scores[22]. In our meta-analysis, post-TORe Sigstad scores were significantly reduced compared to baseline, with a pooled mean 11.1-point reduction (p\u0026lt;0.001). Most studies in this meta-analysis employed simple interrupted or figure-of-eight suturing patterns. While the purse-string technique has demonstrated superior weight loss outcomes compared to interrupted suturing[23], its impact on dumping syndrome efficacy remains unexplored. Future research comparing suturing techniques could clarify their relative effectiveness in this context.\u003c/p\u003e\n\u003cp\u003eOur updated meta-analysis builds upon the 2021 meta-analysis by Bazarbashi et al.[24], which had notable limitations, including the incorporation of conference abstracts. In contrast, our study employed rigorous selection criteria, including only peer-reviewed studies to better evaluate bias risks and achieve more accurate effect estimates. We also incorporated newer studies not present in the prior analysis[13, 16, 20, 24]. Unlike Bazarbashi et al.[24], we assessed the efficacy of TORe for dumping syndrome using objective Sigstad scoring system criteria, demonstrating a significant improvement in Sigstad scores by the endoscopic intervention.\u003c/p\u003e\n\u003cp\u003eDespite the encouraging results, several limitations should be acknowledged. First, the analysis is based exclusively on observational studies, with no randomized controlled trials (RCTs) available to date. This reliance on non-randomized data introduces potential risks of unmeasured confounding and selection bias. Consequently, high-quality prospective series and RCTs would confirm and strengthen the current evidence base. Second, although a random-effects model was employed to account for inter-study variability, significant statistical heterogeneity was observed across many outcomes. This may be attributable to differences in patient characteristics, baseline severity of dumping syndrome, definitions of clinical success, and variability in follow-up durations. Third, the follow-up periods reported in the majority of the included studies were relatively short, limiting the ability to assess long-term durability and outcomes of TORe. Lastly, not all studies provided objective, quantitative pre- and post-procedure assessments using the Sigstad scoring system, which limits the ability to uniformly evaluate treatment response across cohorts.\u003c/p\u003e\n\u003cp\u003eNevertheless, this study has important strengths. To our knowledge, it represents the first meta-analysis to evaluate the efficacy of TORe for dumping syndrome using objective criteria based on Sigstad’s scoring system. By synthesizing available data from multiple international cohorts, this analysis provides valuable insight into the clinical utility of TORe in this challenging patient population.\u003c/p\u003e\n\u003cp\u003eIn conclusion, our findings suggest that TORe is a safe and effective minimally invasive treatment for patients with medically refractory dumping syndrome. TORe should be considered before proceeding to surgical revision, which carries higher morbidity and technical complexity. Further prospective studies, particularly randomized trials with longer follow-up durations, are warranted to validate these findings.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eContributions: Conceptualization and design: AB and MG. Manuscript drafting: AB, AA, DR, KE, and MG. Data collection: AB, AA, and FE. Statistical analysis: AB. Tables: AB, DR, AA. Critical revision of manuscript: MG and NS. Guarantor of article: MG. Final review and approval of the manuscript: All authors.No IRB or Ethics Committee required for this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eFlegal, K.M., et al., \u003cem\u003ePrevalence of obesity and trends in the distribution of body mass index among US adults, 1999-2010.\u003c/em\u003e Jama, 2012. \u003cstrong\u003e307\u003c/strong\u003e(5): p. 491-7.\u003c/li\u003e\n\u003cli\u003eMingrone, G., et al., \u003cem\u003eBariatric-metabolic surgery versus conventional medical treatment in obese patients with type 2 diabetes: 5 year follow-up of an open-label, single-centre, randomised controlled trial.\u003c/em\u003e Lancet, 2015. \u003cstrong\u003e386\u003c/strong\u003e(9997): p. 964-73.\u003c/li\u003e\n\u003cli\u003eEnglish, W.J., et al., \u003cem\u003eAmerican Society for Metabolic and Bariatric Surgery estimation of metabolic and bariatric procedures performed in the United States in 2016.\u003c/em\u003e Surg Obes Relat Dis, 2018. \u003cstrong\u003e14\u003c/strong\u003e(3): p. 259-263.\u003c/li\u003e\n\u003cli\u003eBeran, A., et al., \u003cem\u003ePredictors of marginal ulcer after gastric bypass: a systematic review and meta-analysis.\u003c/em\u003e J Gastrointest Surg, 2023. \u003cstrong\u003e27\u003c/strong\u003e(6): p. 1066-1077.\u003c/li\u003e\n\u003cli\u003eCooper, T.C., et al., \u003cem\u003eTrends in Weight Regain Following Roux-en-Y Gastric Bypass (RYGB) Bariatric Surgery.\u003c/em\u003e Obes Surg, 2015. \u003cstrong\u003e25\u003c/strong\u003e(8): p. 1474-81.\u003c/li\u003e\n\u003cli\u003eBerg, P. and R. McCallum, \u003cem\u003eDumping Syndrome: A Review of the Current Concepts of Pathophysiology, Diagnosis, and Treatment.\u003c/em\u003e Dig Dis Sci, 2016. \u003cstrong\u003e61\u003c/strong\u003e(1): p. 11-8.\u003c/li\u003e\n\u003cli\u003eEmous, M., et al., \u003cem\u003eThe short- to mid-term symptom prevalence of dumping syndrome after primary gastric-bypass surgery and its impact on health-related quality of life.\u003c/em\u003e Surg Obes Relat Dis, 2017. \u003cstrong\u003e13\u003c/strong\u003e(9): p. 1489-1500.\u003c/li\u003e\n\u003cli\u003evan Beek, A.P., et al., \u003cem\u003eDumping syndrome after esophageal, gastric or bariatric surgery: pathophysiology, diagnosis, and management.\u003c/em\u003e Obes Rev, 2017. \u003cstrong\u003e18\u003c/strong\u003e(1): p. 68-85.\u003c/li\u003e\n\u003cli\u003eScarpellini, E., et al., \u003cem\u003eInternational consensus on the diagnosis and management of dumping syndrome.\u003c/em\u003e Nat Rev Endocrinol, 2020. \u003cstrong\u003e16\u003c/strong\u003e(8): p. 448-466.\u003c/li\u003e\n\u003cli\u003eSigstad, H., \u003cem\u003eA clinical diagnostic index in the diagnosis of the dumping syndrome. Changes in plasma volume and blood sugar after a test meal.\u003c/em\u003e Acta Med Scand, 1970. \u003cstrong\u003e188\u003c/strong\u003e(6): p. 479-86.\u003c/li\u003e\n\u003cli\u003eDolan, R.D., P. Jirapinyo, and C.C. Thompson, \u003cem\u003eEndoscopic versus surgical gastrojejunal revision for weight regain in Roux-en-Y gastric bypass patients: 5-year safety and efficacy comparison.\u003c/em\u003e Gastrointestinal Endoscopy, 2021. \u003cstrong\u003e94\u003c/strong\u003e(5): p. 945-950.\u003c/li\u003e\n\u003cli\u003eJirapinyo, P., et al., \u003cem\u003eFive-year outcomes of transoral outlet reduction for the treatment of weight regain after Roux-en-Y gastric bypass.\u003c/em\u003e Gastrointest Endosc, 2020. \u003cstrong\u003e91\u003c/strong\u003e(5): p. 1067-1073.\u003c/li\u003e\n\u003cli\u003eLovis, J., et al., \u003cem\u003eLong-term results after transoral outlet reduction (TORe) of the gastrojejunal anastomosis for secondary weight regain and dumping syndrome after Roux-en-Y gastric bypass.\u003c/em\u003e Surg Endosc, 2024. \u003cstrong\u003e38\u003c/strong\u003e(8): p. 4496-4504.\u003c/li\u003e\n\u003cli\u003ePage, M.J., et al., \u003cem\u003eThe PRISMA 2020 statement: an updated guideline for reporting systematic reviews.\u003c/em\u003e Bmj, 2021. \u003cstrong\u003e372\u003c/strong\u003e: p. n71.\u003c/li\u003e\n\u003cli\u003eStang, A., \u003cem\u003eCritical evaluation of the Newcastle-Ottawa scale for the assessment of the quality of nonrandomized studies in meta-analyses.\u003c/em\u003e Eur J Epidemiol, 2010. \u003cstrong\u003e25\u003c/strong\u003e(9): p. 603-5.\u003c/li\u003e\n\u003cli\u003ePontecorvi, V., et al., \u003cem\u003eLong-term Outcomes of Transoral Outlet Reduction (TORe) for Dumping Syndrome and Weight Regain After Roux-en-Y Gastric Bypass.\u003c/em\u003e Obes Surg, 2023. \u003cstrong\u003e33\u003c/strong\u003e(4): p. 1032-1039.\u003c/li\u003e\n\u003cli\u003eRelly, R., et al., \u003cem\u003eEndoscopic trans-oral outlet reduction after bariatric surgery is safe and effective for dumping syndrome.\u003c/em\u003e Surg Endosc, 2021. \u003cstrong\u003e35\u003c/strong\u003e(12): p. 6846-6852.\u003c/li\u003e\n\u003cli\u003eTsai, C., et al., \u003cem\u003eShort-term outcomes of endoscopic gastro-jejunal revisions for treatment of dumping syndrome after Roux-En-Y gastric bypass.\u003c/em\u003e Surg Endosc, 2020. \u003cstrong\u003e34\u003c/strong\u003e(8): p. 3626-3632.\u003c/li\u003e\n\u003cli\u003eVargas, E.J., et al., \u003cem\u003eEndoscopic management of dumping syndrome after Roux-en-Y gastric bypass: a large international series and proposed management strategy.\u003c/em\u003e Gastrointest Endosc, 2020. \u003cstrong\u003e92\u003c/strong\u003e(1): p. 91-96.\u003c/li\u003e\n\u003cli\u003ePetchers, A., et al., \u003cem\u003eEvaluation of endoscopic gastrojejunostomy revision after Roux-en-Y gastric bypass for treatment of dumping syndrome.\u003c/em\u003e Gastrointest Endosc, 2022. \u003cstrong\u003e96\u003c/strong\u003e(4): p. 639-644.\u003c/li\u003e\n\u003cli\u003eThompson, C.C., et al., \u003cem\u003eEndoscopic suturing for transoral outlet reduction increases weight loss after Roux-en-Y gastric bypass surgery.\u003c/em\u003e Gastroenterology, 2013. \u003cstrong\u003e145\u003c/strong\u003e(1): p. 129-137.e3.\u003c/li\u003e\n\u003cli\u003eTack, J., et al., \u003cem\u003ePathophysiology, diagnosis and management of postoperative dumping syndrome.\u003c/em\u003e Nat Rev Gastroenterol Hepatol, 2009. \u003cstrong\u003e6\u003c/strong\u003e(10): p. 583-90.\u003c/li\u003e\n\u003cli\u003eSchulman, A.R., N. Kumar, and C.C. Thompson, \u003cem\u003eTransoral outlet reduction: a comparison of purse-string with interrupted stitch technique.\u003c/em\u003e Gastrointest Endosc, 2018. \u003cstrong\u003e87\u003c/strong\u003e(5): p. 1222-1228.\u003c/li\u003e\n\u003cli\u003eBazarbashi, A.N., et al., \u003cem\u003eEndoscopic revision of gastrojejunal anastomosis for the treatment of dumping syndrome in patients with Roux-en-Y gastric bypass: a systematic review and meta-analysis.\u003c/em\u003e Surg Endosc, 2022. \u003cstrong\u003e36\u003c/strong\u003e(6): p. 4099-4107.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"obesity-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"obsu","sideBox":"Learn more about [Obesity Surgery](https://link.springer.com/journal/11695)","snPcode":"11695","submissionUrl":"https://submission.springernature.com/new-submission/11695/3","title":"Obesity Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"transoral outlet reduction, gastrojejunal anastomosis revision, Roux-en-Y gastric bypass, dumping syndrome","lastPublishedDoi":"10.21203/rs.3.rs-7024238/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7024238/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction:\u003c/h2\u003e\u003cp\u003eDumping syndrome is a complication of Roux-en-Y gastric bypass (RYGB) surgery that can significantly affect quality of life. Transoral outlet reduction (TORe) is a minimally invasive endoscopic procedure that reduces the size of the gastrojejunal anastomosis (GJA) through ablation and/or endoscopic suturing, primarily used to address weight regain after RYGB. Emerging evidence highlights the feasibility and safety of TORe as a treatment for medically refractory dumping syndrome. This meta-analysis aims to evaluate the efficacy and safety of TORe for dumping syndrome.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eA systematic search of PubMed, Embase, and Web of Science was conducted through December 2024. Primary outcomes included clinical success (defined as sustained symptom improvement without requiring repeat TORe or revisional surgery at last follow-up) and the mean difference in pre- and post-procedural Sigstad\u0026rsquo;s score assessments. Secondary outcomes included rates of post-TORe surgery, repeat TORe, and serious adverse events. Pooled rate estimates and mean differences (MD) with the corresponding 95% confidence intervals (CI) were calculated using random-effects models.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eSix studies with 333 post-RYGB patients with dumping syndrome were included. The pooled clinical success of TORe was 83% (95% CI 71%-90%, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;74%). Furthermore, TORe resulted in a significant improvement in Sigstad\u0026rsquo;s score (MD \u0026minus;\u0026thinsp;11.12 [95% CI -15.33 to \u0026minus;\u0026thinsp;6.91], P\u0026thinsp;\u0026lt;\u0026thinsp;0.001, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;89%). The rate of serious adverse events was 3% (95% CI 0.7%-12.4%, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;68%).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eOur findings suggest that TORe is a safe and effective minimally invasive treatment for patients with medically refractory dumping syndrome. Further prospective studies with longer follow-up durations are warranted to validate these findings.\u003c/p\u003e","manuscriptTitle":"Transoral Outlet Reduction for Dumping Syndrome after Roux-En-Y Gastric Bypass: A Systematic Review and Meta-Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-23 08:31:45","doi":"10.21203/rs.3.rs-7024238/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-30T19:52:49+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-30T05:53:13+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-29T02:56:40+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-29T01:21:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"255929406675474148820595274325070273626","date":"2025-07-20T19:50:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"183694493346766055132984580059372720039","date":"2025-07-18T05:40:01+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"25373787082519432447591541697711562975","date":"2025-07-17T11:43:09+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-17T11:35:48+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-08T21:04:41+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-07T13:43:48+00:00","index":"","fulltext":""},{"type":"submitted","content":"Obesity Surgery","date":"2025-07-02T01:52:35+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"obesity-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"obsu","sideBox":"Learn more about [Obesity Surgery](https://link.springer.com/journal/11695)","snPcode":"11695","submissionUrl":"https://submission.springernature.com/new-submission/11695/3","title":"Obesity Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7704a442-a2c9-403b-b94e-c8ad8e1362b7","owner":[],"postedDate":"July 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-09-29T16:06:40+00:00","versionOfRecord":{"articleIdentity":"rs-7024238","link":"https://doi.org/10.1007/s11695-025-08275-9","journal":{"identity":"obesity-surgery","isVorOnly":false,"title":"Obesity Surgery"},"publishedOn":"2025-09-27 15:57:40","publishedOnDateReadable":"September 27th, 2025"},"versionCreatedAt":"2025-07-23 08:31:45","video":"","vorDoi":"10.1007/s11695-025-08275-9","vorDoiUrl":"https://doi.org/10.1007/s11695-025-08275-9","workflowStages":[]},"version":"v1","identity":"rs-7024238","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7024238","identity":"rs-7024238","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}