Retrospective cohort study of 925 OAGB procedures. The UK MGB/OAGB collaborative group

Metabolic and Bariatric Surgeon Criteria-An International Experts' Consensus

PURPOSE

With the global epidemic of obesity, the importance of metabolic and bariatric surgery (MBS) is greater than ever before. Performing these surgeries requires academic training and the completion of a dedicated fellowship training program. This study aimed to develop guidelines based on expert consensus using a modified Delphi method to create the criteria for metabolic and bariatric surgeons that must be mastered before obtaining privileges to perform MBS.

METHODS

Eighty-nine recognized MBS surgeons from 42 countries participated in the Modified Delphi consensus to vote on 30 statements in two rounds. An agreement/disagreement among ≥ 70.0% of the experts was regarded to indicate a consensus.

RESULTS

Consensus was reached on 29 out of 30 statements. Most experts agreed that before getting privileges to perform MBS, surgeons must hold a general surgery degree and complete or have completed a dedicated fellowship training program. The experts agreed that the learning curves for the various operative procedures are approximately 25-50 operations for the LSG, 50-75 for the OAGB, and 75-100 for the RYGB. 93.1% of experts agreed that MBS surgeons should diligently record patients' data in their National or Global database.

CONCLUSION

MBS surgeons should have a degree in general surgery and have been enrolled in a dedicated fellowship training program with a structured curriculum. The learning curve of MBS procedures is procedure dependent. MBS surgeons must demonstrate proficiency in managing postoperative complications, collaborate within a multidisciplinary team, commit to a minimum 2-year patient follow-up, and actively engage in national and international MBS societies.

Pros and cons of partial reversal with gastro-gastrostomy in patients with refractory hypoalbuminemia following one-anastomosis gastric bypass

PURPOSE

Hypoalbuminemia following One-Anastomosis Gastric Bypass (OAGB) surgery remains a major concern among bariatric surgeons. This study aims to assess the outcome of partial reversal to normal anatomy with gastro-gastrostomy alone in patients with refractory hypoalbuminemia following OAGB surgery.

METHODS

A retrospective study was performed on patients who underwent partial reversal surgery with gastro-gastrostomy alone due to refractory hypoalbuminemia post-OAGB surgery, using data from the Iran National Obesity Surgery Database, from 2013 to 2022.

RESULTS

Of 4640 individuals undergoing OAGB, 11 underwent gastro-gastrostomy due to refractory hypoalbuminemia. The median time from OAGB to partial reversal was 16.6 months and the BPL length ranged from 155 to 200 cm. The follow-up period ranged from 1 to 7 years. The mean BMI was 27.3 (7.5) kg/m² before partial reversal. The mean BMI post-reversal was 30.9 (4.2) kg/m² after 1 year and 33.3 (3.8) kg/m² after 2 years. Serum albumin levels significantly increased from 3.0 (0.4) g/dL to 4.0 (0.5) g/dL following gastro-gastrostomy (p-value < 0.001). Serum liver enzymes (SGOT, SGPT, ALP) significantly decreased post-gastro-gastrostomy (p-value < 0.05). Nine individuals (81.8%) achieved resolution of hypoalbuminemia after gastro-gastrostomy with maintenance of ≥ 20% TWL and ≥ 50% EWL. No cases of anastomotic stricture, leak, bleeding, or major complications were reported after gastro-gastrostomy.

CONCLUSION

Gastro-gastrostomy appears to be a safe and efficacious technique for addressing refractory hypoalbuminemia following OAGB. The procedure preserves the weight loss achieved following OAGB without significant complications. However, further studies are required to validate these findings.

Revision/Conversion Surgeries After One Anastomosis Gastric Bypass-An Experts' Modified Delphi Consensus

PURPOSE

There is a lack of evidence for treatment of some conditions including complication management, suboptimal initial weight loss, recurrent weight gain, or worsening of a significant obesity complication after one anastomosis gastric bypass (OAGB). This study was designed to respond to the existing lack of agreement and to provide a valuable resource for clinicians by employing an expert-modified Delphi consensus method.

METHODS

Forty-eight recognized bariatric surgeons from 28 countries participated in the modified Delphi consensus to vote on 64 statements in two rounds. An agreement/disagreement among ≥ 70.0% of the experts was regarded to indicate a consensus.

RESULTS

A consensus was achieved for 46 statements. For recurrent weight gain or worsening of a significant obesity complication after OAGB, more than 85% of experts reached a consensus that elongation of the biliopancreatic limb (BPL) is an acceptable option and the total bowel length measurement is mandatory during BPL elongation to preserve at least 300-400 cm of common channel limb length to avoid nutritional deficiencies. Also, more than 85% of experts reached a consensus on conversion to Roux-en-Y gastric bypass (RYGB) with or without pouch downsizing as an acceptable option for the treatment of persistent bile reflux after OAGB and recommend detecting and repairing any size of hiatal hernia during conversion to RYGB.

CONCLUSION

While the experts reached a consensus on several aspects regarding revision/conversion surgeries after OAGB, there are still lingering areas of disagreement. This highlights the importance of conducting further studies in the future to address these unresolved issues.

American Society for Metabolic and Bariatric Surgery position statement on one-anastomosis gastric bypass

The following position statement is issued by the American Society for Metabolic and Bariatric Surgery in response to inquiries made to the society by patients, physicians, society members, hospitals, health insurance payors, and others regarding one-anastomosis gastric bypass as a treatment for obesity and metabolic disease. This statement is based on current clinical knowledge, expert opinion, and published peer-reviewed scientific evidence available at this time. The statement may be revised in the future as more information becomes available.

Outcomes of One-Anastomosis Gastric Bypass Conversion to Roux-en-Y Gastric Bypass for Severe Obesity: A Systematic Review and Meta-analysis

One-anastomosis gastric bypass (OAGB) is an effective procedure to treat severe obesity. However, conversion to Roux-en-Y gastric bypass (RYGB) is increasing. We therefore conducted a systematic review to determine the safety and efficacy associated with OAGB-RYGB conversion. A systematic search was conducted by three independent reviewers using Medline, Embase, and the Cochrane library following PRISMA guidelines. Six studies including 134 patients were selected who were undergoing OAGB-RYGB conversion. The most common indications were reflux (47.8%), malnutrition (31.3%), and inadequate weight loss (8.2%). Study outcomes demonstrated 100% resolution of bile reflux. Overall, there was medium-term weight gain of 0.61 BMI. OAGB to RYGB conversion leads to resolution of reflux symptoms. However, it is associated with weight regain, albeit this may be acceptable to patients to treat biliary reflux.

Current recommendations for procedure selection in class I and II obesity developed by an expert modified Delphi consensus

Metabolic and bariatric surgery (MBS) is widely considered the most effective option for treating obesity, a chronic, relapsing, and progressive disease. Recently, the American Society of Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) issued new guidelines on the indications for MBS, which have superseded the previous 1991 National Institutes of Health guidelines. The aim of this study is to establish the first set of consensus guidelines for selecting procedures in Class I and II obesity, using an Expert Modified Delphi Method. In this study, 78 experienced bariatric surgeons from 32 countries participated in a two-round Modified Delphi consensus voting process. The threshold for consensus was set at an agreement or disagreement of ≥ 70.0% among the experts. The experts reached a consensus on 54 statements. The committee of experts reached a consensus that MBS is a cost-effective treatment option for Class II obesity and for patients with Class I obesity who have not achieved significant weight loss through non-surgical methods. MBS was also considered suitable for patients with Type 2 diabetes mellitus (T2DM) and a body mass index (BMI) of 30 kg/m2 or higher. The committee identified intra-gastric balloon (IGB) as a treatment option for patients with class I obesity and endoscopic sleeve gastroplasty (ESG) as an option for patients with class I and II obesity, as well as for patients with T2DM and a BMI of ≥ 30 kg/m2. Sleeve gastrectomy (1) and Roux-en-Y gastric bypass (RYGB) were also recognized as viable treatment options for these patient groups. The committee also agreed that one anastomosis gastric bypass (OAGB) is a suitable option for patients with Class II obesity and T2DM, regardless of the presence or severity of obesity-related medical problems. The recommendations for selecting procedures in Class I and II obesity, developed through an Expert Modified Delphi Consensus, suggest that the use of standard primary bariatric endoscopic (IGB, ESG) and surgical procedures (SG, RYGB, OAGB) are acceptable in these patient groups, as consensus was reached regarding these procedures. However, randomized controlled trials are still needed in Class I and II Obesity to identify the best treatment approach for these patients in the future.

A systematic review and meta-analysis on GERD after OAGB: rate, treatments, and success

INTRODUCTION

This review aims to investigate the gastroesophageal reflux disease (GERD) as one of the important concerns for both surgeons and patients after one anastomosis gastric bypass (OAGB).

METHOD

PubMed, Scopus, Embase, Web of Science, and Cochrane were reviewed by the end of the 2021 with keywords relating to GERD, OAGB, and their equivalents. Data regarding OAGB, number of patients with GERD, treatment for GERD, endoscopy findings, the interval between GERD and OAGB were retrieved by two independent investigators. The primary effect/effect size measure was prevalence.

RESULTS

40 studies examining 17,299 patients were included revealing that 2% of patients experience GERD following OAGB. Reflux after revisional OAGB is six times higher than primary OAGB. Despite being unclear, medical and surgical treatments for GERD after OAGB were used in 60% and 41% of patients with estimated success rate of 85% and 100%, respectively.

CONCLUSION

Based on how GERD was identified after OAGB, its rate ranged from 0 to 55%; the pooled rate of 2% is near to Roux-en-Y gastric bypass. GERD symptoms can be mild to be tolerated without medical treatment, moderate that respond to acid-reducing agents, or severe enough that are categorized as interactable and would need a surgical intervention.

Does One-Anastomosis Gastric Bypass Expose Patients to Gastroesophageal Reflux: a Systematic Review and Meta-analysis

This systematic review and meta-analysis aimed to investigate the incidence of new-onset gastroesophageal reflux, reflux change, esophagitis, Barrett's esophagus, and revision due to reflux, gastritis, and marginal ulcer after one-anastomosis gastric bypass (OAGB). We performed subgroup analyses based on primary and revisional OAGB and time of follow-up. Meta-analysis of 87 studies with 27,775 patients showed a 6% rate of new-onset reflux after OAGB. Preoperative reflux status did not change significantly after OAGB. The rate of esophagitis and Barrett's esophagus was 15% and 1%, respectively. The new-onset reflux rate after OAGB was significantly higher than gastric bypass but not different with sleeve gastrectomy. The current study showed a relatively low rate of reflux and its complications after OAGB, but it was significantly higher than Roux-en-Y gastric bypass.

One Anastomosis Gastric Bypass in 6722 Patients: Early Outcomes from a Private Hospital Registry

BACKGROUND

One-anastomosis gastric bypass (OAGB) is an emerging metabolic bariatric surgery (MBS) type used in both primary OAGB (pOAGB) and revisional OAGB (rOAGB). We studied ≤30-day outcomes of pOAGB and rOAGB and identified predictors of early complications.

METHODS

Electronic medical records of all OAGBs performed between January 2017 and December 2021 at a high-volume bariatric clinic in Israel comprising four hospital centers were scanned retrospectively using specialized data software (MDClone software, version 6.1). Data gathered were patients' characteristics, surgical procedure, and ≤30-day complications with Clavien-Dindo Classification (CDC). Multivariate logistic regression analyses were used to identify factors related to early complications of pOAGB and rOAGB.

RESULTS

A total of 6722 patients underwent a pOAGB (n = 5088, 75.7%) or rOAGB (n = 1634, 24.3%) procedure at our institution. Preoperative mean age and body mass index (BMI) were 40.6 ± 11.5 years and 41.2 ± 4.6 kg/m2, respectively. Early complications occurred in 258 (3.8%) patients (176 pOAGB and 82 rOAGB) and included mainly bleeding (n = 133, 2.0%), leaks (n = 31, 0.5%), and obstruction/strictures (n = 19, 0.3%). CDC complications for grades 1-2 and grades 3a--5 were 1.5% and 1.6%, respectively. The overall mortality rate was 0.03% (n = 2). Age, operative time ≥3 h, and any additional concomitant procedure were independent predictors of early complications following pOAGB, while a diagnosis of diabetes mellitus and operative time ≥3 h were independent predictors of early complications following rOAGB.

CONCLUSIONS

OAGB was found to be a safe primary and revisional MBS procedure in the ≤30-postoperative day term. The most common complications were gastrointestinal bleeding, leaks, and obstruction/stricture.

Bile reflux after bariatric surgery

The growing epidemic of obesity and the increase in weight loss surgery has led to a resurgence of interest in biliary reflux because anatomical alterations may be refluxogenic. HIDA scan is the least invasive scan with good patient tolerability, sensitivity and reproducibility for the diagnosis of biliary reflux. Patients with more advanced oesophageal lesions have a higher degree of duodenal reflux. It has been shown in animal models and in vitro that there is more Barrett's and dysplasia with duodenal reflux. There are two cases of post-OAGB malignancy reported in 20 years, both without correlation with a biliary aetiology, so the carcinogenic risk probably remains theoretical. Prospective trials on OAGB should include endoscopy preoperatively and at 5-year intervals, to have data on the real effects of bile exposure on the gastric reservoir and oesophagus.

Emergent conversion from single-anastomosis gastric bypass to Roux-en-Y gastric bypass with subsequent obstruction of entero-enteric anastomosis by ascaris

One anastomosis gastric bypass (OAGB), the third most commonly performed procedure worldwide, has shown excellent results in terms of weight loss and resolution of comorbidities compared with other bariatric surgeries. However, its use remains limited in various parts of the world due to postoperative complications. After the efficacy of this procedure was established, the focus of treatment shifted toward resolving postoperative complications. Protein-energy malnutrition after OAGB is one of the main issues that needs to be addressed. There are several operative options for patients who require revision surgery including reversal and conversion to Roux-en-Y gastric bypass (RYGB). The conversion from OAGB to RYGB is a feasible method that has shown excellent results when performed by experts in the field. Here, we present the case of a woman with symptoms of acute obstruction secondary to OAGB who underwent conversion to RYGB under emergent conditions.

Protein malnutrition after Roux-en-Y gastric bypass: a challenging case and scoping review of the literature

Although protein malnutrition (PM) is often reported after highly malabsorptive procedures, its exact incidence and mechanisms after Roux-en-Y gastric bypass (RYGB) are poorly understood. The aim of this study was to present a challenging clinical case of PM after RYGB and conduct a scoping review of the literature. Among the 18 studies with 3015 RYGB patients included in the review, the median incidence of PM was 1.7% (range, 0%-8.9%), and it was diagnosed 12 to 120 months after RYGB. The most common cause is insufficient oral intake of protein; however, in cases of persistent hypoalbuminemia, a thorough diagnostic workup needs to be performed. Risk factors for PM after RYGB include specific triggering events such as intractable vomiting and dysphagia, and a total alimentary limb length less than 250 to 300 cm.

Comparison of One Anastomosis Gastric Bypass and Sleeve Gastrectomy for Revision of Laparoscopic Adjustable Gastric Banding: 5-Year Outcomes

PURPOSE

Laparoscopic adjustable gastric banding (LAGB) is in continuous decline due to low effectiveness and high reoperation rates. This study aims to evaluate outcomes of converting LAGB to one anastomosis gastric bypass (OAGB) and sleeve gastrectomy (SG) for insufficient weight loss or weight regain.

MATERIALS AND METHODS

Retrospective comparative study, based on prospective registry database of a tertiary center (2012-2019).

RESULTS

In all, 276 LAGB patients were converted to OAGB (n = 125) and SG (n = 151). Body mass index (BMI) at revision was 41.3 ± 6.6 and 42.3 ± 9.6 kg/m2 (P = 0.34) in OAGB and SG patients, respectively. Time interval was longer in OAGB patients (p < 0.001). Major early complication rates were comparable (2.4% and 4%; p = 0.46). At 5-years, OAGB patients had lower BMI (31.9 vs. 34.5 kg/m2; p = 0.002), and a higher total weight loss (25.1% vs. 18.8%; p = 0.003), compared with SG patients. Resolution of type 2 diabetes was higher in OAGB patients (93.3% vs. 66.6%; p = 0.047), while resolution of hypertension was not significantly different (84.6% and 80.5%; p = 0.68). Revision due to delayed complications was required in five (4%) OAGB patients and nine (8.6%) SG patients (p = 0.14).

CONCLUSION

OAGB for revision after LAGB due to insufficient weight loss or weight regain is safe, and has better effectiveness in weight reduction and resolution of type 2 diabetes than SG.

Mechanisms linking bariatric surgery to adipose tissue, glucose metabolism, fatty liver disease and gut microbiota

PURPOSE

In the last 20 years, bariatric surgery has achieved an important role in translational and clinical research because of obesity comorbidities. Initially, a tool to lose weight, bariatric surgery now has been shown to be involved in several metabolic pathways.

METHODS

We conducted a narrative review discussing the underlying mechanisms that could explain the impact of bariatric surgery and the relationship between obesity and adipose tissue, T2D, gut microbiota, and NAFLD.

RESULTS

Bariatric surgery has an impact in the relation between obesity and type 2 diabetes, but in addition  it induces the white-to-brown adipocyte trans-differentiation, by enhancing thermogenesis. Another issue is the connection of bariatric surgery with the gut microbiota and its role in the complex mechanism underlying weight gain.

CONCLUSION

Bariatric surgery modifies gut microbiota, and these modifications influence lipid metabolism, leading to improvement of non-alcoholic fatty liver disease.

Laparoscopic conversion of omega loop gastric bypass to Roux-en-Y gastric bypass for Barrett's esophagus: case report

BACKGROUND

The number of mini gastric bypass / one anastomosis bypass (MGB-OAGB) procedures in bariatric patients that have been performed world-wide has drastically increased during the past decade. Nevertheless, due to the risk of subsequent biliary reflux and development of ulcer and neoplastic (pre)lesions caused by long-time bile exposure, the procedure is still controversially discussed. In here presented case report, we could endoscopically demonstrate a transformation from reflux oesophagitis to Barrett's metaplasia most likely caused by bile reflux after mini-gastric bypass. To our knowledge, this is a first case study that shows development of Barrett's metaplasia after MGB-OAGB.

CASE PRESENTATION

We present the case of a 50-year-old female which received a mini-gastric bypass due to morbid obesity (body mass index (BMI) 42.4 kg/m²). Because of history gastroesophageal reflux disease (GERD), a fundoplication had been performed earlier. Preoperative gastroscopy showed reflux esophagitis (Los Angeles classification grade B) with no signs of Barrett's metaplasia. Three months post mini-gastric bypass, the patient complained about severe bile reflux under 40 mg pantoprazole daily. Six months postoperative, Endoscopically Barrett's epithelium was detected and histopathologically confirmed (C1M0 after Prague classification). A conversion into Roux-en-Y gastric bypass was performed. The postoperative course was without complications. In a follow up after 6 months the patient denied reflux and showed no signs of malnutrition.

CONCLUSIONS

The rapid progress from inflammatory changes of the distal esophagus towards Barrett's metaplasia under bile reflux in our case is most likely a result of previous reflux disease. Nevertheless, bile reflux appears to be a potential decisive factor. Study results regarding presence of bile reflux or development of endoscopically de-novo findings after MGB-OAGB are widely non-conclusive. Long-term prospective studies with regular endoscopic surveillance independent of clinical symptoms are needed.

Gastroesophageal Reflux Disease as an Indication of Revisional Bariatric Surgery-Indication and Results-a Systematic Review and Metanalysis

This systematic review evaluates the indications and results of revisional bariatric surgery (RBS) in gastroesophageal reflux disease (GERD). A systematic literature search and meta-analysis was performed for articles published by April 1, 2021. After examining 722 papers involving 17,437 patients, 48 studies were included (n = 915 patients). RBS for GERD was mostly reported after sleeve gastrectomy (n = 796, 87%) and one anastomosis gastric bypass (n = 62, 6.8%) and was performed due to intractable GERD (71.6%), GERD and weight issues (16%), and biliary reflux (6.2%). Mean follow-up of the studies was 31.5 (3-84) months. Pooled estimation of a meta-analysis of studies reported 7% of GERD following primary surgery needing RBS, in which 99% of the patients experienced remission.

Revisional Surgery of One Anastomosis Gastric Bypass for Severe Protein–Energy Malnutrition

Background: One anastomosis gastric bypass (OAGB) is safe and effective. Its strong malabsorptive component might cause severe protein–energy malnutrition (PEM), necessitating revisional surgery. We aimed to evaluate the safety and outcomes of OAGB revision for severe PEM. Methods: This was a single-center retrospective analysis of OAGB patients undergoing revision for severe PEM (2015–2021). Perioperative data and outcomes were retrieved. Results: Ten patients underwent revision for severe PEM. Our center’s incidence is 0.63% (9/1425 OAGB). All patients were symptomatic. Median (interquartile range) EWL and lowest albumin were 103.7% (range 57.6, 114) and 24 g/dL (range 19, 27), respectively, and 8/10 patients had significant micronutrient deficiencies. Before revision, nutritional optimization was undertaken. Median OAGB to revision interval was 18.4 months (range 15.7, 27.8). Median BPL length was 200 cm (range 177, 227). Reversal (n = 5), BPL shortening (n = 3), and conversion to Roux-en-Y gastric bypass (RYGB) (n = 2) were performed. One patient had anastomotic leak after BPL shortening. No death occurred. Median BMI and albumin increased from 22.4 kg/m² (range 20.6, 30.3) and 35.5 g/dL (range 29.2, 41), respectively, at revision to 27.5 (range 22.2, 32.4) kg/m² and 39.5 g/dL (range 37.2, 41.7), respectively, at follow-up (median 25.4 months, range 3.1, 45). Complete resolution occurs after conversion to RYGB or reversal to normal anatomy, but not after BPL shortening. Conclusions: Revisional surgery of OAGB for severe PEM is feasible and safe after nutritional optimization. Our results suggest that the type of revision may be an important factor for PEM resolution. Comparative studies are needed to define the role of each revisional option.

Effect of Biliopancreatic Limb Length on Weight Loss, Postoperative Complications, and Remission of Comorbidities in One Anastomosis Gastric Bypass: a Systematic Review and Meta-analysis

Aimed to evaluate the effects of biliopancreatic limb (BPL) length on weight loss, postoperative complications, and remission of comorbidities in OAGB.. An extensive search was conducted in PubMed, Scopus, EMBASE, and Google Scholar databases to find related OAGB articles. Both BPL length < 200 cm (by - 17.79, 95% CI - 19.23, - 16.34) and BPL length ≥ 200 cm (by - 14.93, 95% CI - 15.66, - 14.20) significantly decreased BMI. Regarding the effect of BPL length on comorbidities and postoperative complications, it was shown that BPL length < 200 cm is safer and more effective. Therefore, standardization of BPL length < 200 cm is suggested. Bypassing ≥ 200 cm of the small bowel does not ameliorate weight loss or resolve comorbidities significantly, and it is related to more frequent postoperative complications and nutritional deficiencies. Registration number in PROSPERO: PROSPERO 2021 CRD42021225499.

Revisional Surgery After One Anastomosis/Minigastric Bypass: an Italian Multi-institutional Survey

BACKGROUND

Efficacy and safety of OAGB/MGB (one anastomosis/mini gastric bypass) have been well documented both as primary and as revisional procedures. However, even after OAGB/MGB, revisional surgery is unavoidable in patients with surgical complications or insufficient weight loss.

METHODS

A questionnaire asking for the total number and demographics of primary and revisional OAGB/MGBs performed between January 2006 and July 2020 was e-mailed to all S.I.C. OB centres of excellence (annual caseload > 100; 5-year follow-up > 50%). Each bariatric centre was asked to provide gender, age, preoperative body mass index (BMI) and obesity-related comorbidities, previous history of abdominal or bariatric surgery, indication for surgical revision of OAGB/MGB, type of revisional procedure, pre- and post-revisional BMI, peri- and post-operative complications, last follow-up (FU).

RESULTS

Twenty-three bariatric centres (54.8%) responded to our survey reporting a total number of 8676 primary OAGB/MGBS and a follow-up of 62.42 ± 52.22 months. A total of 181 (2.08%) patients underwent revisional surgery: 82 (0.94%) were suffering from intractable DGER (duodeno-gastric-esophageal reflux), 42 (0.48%) were reoperated for weight regain, 16 (0.18%) had excessive weight loss and malnutrition, 12 (0.13%) had a marginal ulcer perforation, 10 (0.11%) had a gastro-gastric fistula, 20 (0.23%) had other causes of revision. Roux-en-Y gastric bypass (RYGB) was the most performed revisional procedure (109; 54%), followed by bilio-pancreatic limb elongation (19; 9.4%) and normal anatomy restoration (19; 9.4%).

CONCLUSIONS

Our findings demonstrate that there is acceptable revisional rate after OAGB/MGB and conversion to RYGB represents the most frequent choice.

Conversion from one-anastomosis gastric bypass to Roux-en-Y gastric bypass: when and why-a single-center experience of all consecutive OAGB procedures

BACKGROUND

One-anastomosis gastric bypass (OAGB) is a well-established treatment method in patients with morbid obesity. Its long-term impact on de novo reflux, anastomotic complications, and malnutrition needs further evaluation. Roux-en-Y gastric bypass (RYGB) is a technically feasible procedure in revisional bariatric surgery. This study presents our institutional data on conversion from OAGB to RYGB.

OBJECTIVE

To determine the reasons for conversion, preoperative endoscopic findings, and feasibility of revisional bariatric surgery after OAGB.

SETTING

University hospital in Austria METHODS: Retrospective analysis of a prospectively fed database. All patients undergoing OAGB between January 2012 and December 2019 were included. Screening was carried out for all patients needing conversion to RYGB. Percent total weight loss, percent excess weight loss, time to conversion, postoperative complications, and reasons for conversion were assessed.

RESULTS

Eighty-two of 1,025 patients who underwent OAGB were converted laparoscopically to RYGB. Seven patients were converted early because of anastomotic/gastric tube leakage. Median time to late conversion was 29.1 ± 24.3 months, mean percent excess weight loss was 86.6% ± 33.1% and percent total weight loss was 35.1% ± 13.5%. Forty-two patients were converted because of reflux, 11 because of persistent marginal ulcers, 10 because of anastomotic stenosis, 9 because of malnutrition, and 3 because of weight regain. Seven patients showed Barrett's metaplasia in biopsies at the gastroesophageal junction before conversion.

CONCLUSION

Laparoscopic conversion from OAGB to RYGB is technically feasible with a moderate rate of postoperative complications. Severe (bile) reflux is a serious long-term complication after OAGB, with 4.1% of patients needing conversion to RYGB. Endoscopy after OAGB in patients showing clinical symptoms of gastroesophageal reflux disease is strongly advised to detect underlying pathologic changes.

Network Meta-Analysis of Metabolic Surgery Procedures for the Treatment of Obesity and Diabetes

Background

Metabolic surgery is part of a well-established treatment intensification strategy for obesity and its related comorbidities including type 2 diabetes (T2DM). Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG) and one-anastomosis gastric bypass (OAGB) are the most commonly performed metabolic surgeries worldwide, but comparative efficacy is uncertain. This study employed network meta-analysis to compare weight loss, T2DM remission and perioperative complications in adults between RYGB, SG and OAGB.

Methods

MEDLINE, EMBASE, trial registries were searched for randomised trials comparing RYGB, SG and OAGB. Study outcomes were excess weight loss (at 1, 2 and 3–5 years), trial-defined T2DM remission at any time point and perioperative complications.

Results

Twenty randomised controlled trials were included involving 1803 patients investigating the three metabolic surgical interventions. RYGB was the index for comparison. The excess weight loss (EWL) demonstrated minor differences at 1 and 2 years, but no differences between interventions at 3–5 years. T2DM remission was more likely to occur with either RYGB or OAGB when compared to SG. Perioperative complications were higher with RYGB when compared to either SG or OAGB. Two-way analysis of EWL and T2DM remission against the risk of perioperative complications demonstrated OAGB was the most positive on this assessment at all time points.

Conclusion

OAGB offers comparable metabolic control through weight loss and T2DM remission to RYGB and SG whilst minimising perioperative complications.

Registration number: CRD42020199779 (https:// www.crd.york.ac.uk/PROSPERO)

Graphical abstract

Conversion of One-Anastomosis Gastric Bypass (OAGB) to Roux-en-Y Gastric Bypass (RYGB) is Effective in Dealing with Late Complications of OAGB: Experience from a Tertiary Bariatric Center and Literature Review

Purpose

Both primary and revisional bariatric surgery are on the rise due to global obesity pandemic. This study aimed to assess the indications for revision after one-anastomosis gastric bypass (OAGB) and the outcomes after laparoscopic conversion of OAGB to roux-en-y gastric bypass (RYGB).

Materials and Methods

Retrospective review on patients that had undergone conversion of OAGB to RYGB between June 2007-June 2019 in a tertiary bariatric center, followed by literature review.

Results

Out of 386 revisional bariatric surgery, a total of 14 patients underwent laparoscopic conversion of OAGB to RYGB. The mean age was 44.7 with 71% female. The mean pre-revision BMI was 29.2 kg/m². The primary indications for revision were bile reflux (n=7), marginal ulcer (n=3), inadequate weight loss or weight regain (IWL/WR) (n=3) and protein-calorie malnutrition (n=1). Conversion of OAGB to RYGB was completed laparoscopically in all cases. The mean length of stay was 4.1 days. There was no intraoperative or early post-operative complication. The mean total weight loss (rTWL%) after revision at year one, year three and year five post-revision were 11.5%, 18.1% and 29.1%, respectively. All patients achieved resolution of bile reflux and marginal ulcer. There was no mortality in this cohort.

Conclusion

Bile reflux, marginal ulcer, IWL/WR and malnutrition were the main indications for revision after OAGB in this study. In concordance with the available evidence, laparoscopic conversion of OAGB to RYGB was safe and effective in dealing with late complications of OAGB.

IFSO Update Position Statement on One Anastomosis Gastric Bypass (OAGB)

The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) issued a position statement on the role of one anastomosis gastric bypass (OAGB) in the field of bariatric/metabolic surgery in 2018 De Luca et al. (Obes Surg. 28(5):1188-206, 2018). This position statement was issued by the IFSO OAGB task force and approved by the IFSO Scientific Committee and IFSO Executive Board. In 2018, the OAGB task force recognized the necessity to update the position statement in the following 2 years since additional high-quality data could emerge. The updated IFSO position statement on OAGB was issued also in response to inquiries to the IFSO by society members, universities, hospitals, physicians, insurances, patients, policy makers, and media. The IFSO position statement on OAGB has been reviewed within 2 years according to the availability of additional scientific evidence. The recommendation of the statement is derived from peer-reviewed scientific literature and available knowledge. The IFSO update position statement on OAGB will again be reviewed in 2 years provided additional high-quality studies emerge.

Effect of one anastomosis gastric bypass on liver function tests: A comparison between 150 cm and 200 cm biliopancreatic limbs

Context:

Some studies have shown that one anastomosis gastric bypass (OAGB) results in the derangement of liver function tests (LFTs). We wanted to study this in our patients.

Aims:

The aims are to study the effect of OAGB on LFTs and to compare the effect of a biliopancreatic limb (BPL) of 150 cm (OAGB-150) to a BPL of 200 cm (OAGB-200).

Settings and Design:

The study was a retrospective cohort study conducted at a university hospital.

Materials and Methods:

Information was obtained from our prospectively maintained database and hospital's computerised records.

Statistical Analysis:

A P < 0.05 was regarded statistically significant; however, given the number of variables examined, findings should be regarded as exploratory.

Results:

A total of 405 patients underwent an OAGB-200 (n = 234) or OAGB-150 (n = 171) in our unit between October 2012 and July 2018. There were significant improvements in gamma-glutamyl transpeptidase (GGT) levels at 1 and 2 years after OAGB-200 and significant worsening in the levels of alkaline phosphatase (ALP) and albumin at 1 and 2 years. There was a significant improvement in GGT levels at 1 and 2 years after OAGB-150 and in alanine transaminase levels at 1 year. There was a significant worsening in ALP and albumin levels at both follow-up points in this group. OAGB-150 group had a significantly lower bilirubin level at 1 year and significantly fewer abnormal ALP values at 2 years in comparison with OAGB-200 patients.

Conclusions:

This exploratory study demonstrates the overall safety of OAGB with regard to its effect on LFTs, with no remarkable difference between OAGB-150 and OAGB-200.

Changes in Anthropometric Measures, Nutritional Indices and Gastrointestinal Symptoms Following One Anastomosis Gastric Bypass (OAGB) Compared with Roux-en-y Gastric Bypass (RYGB)

Purpose

Bariatric surgery is an effective treatment for obesity with new procedures emerging. However, despite comparable weight loss and improvements in metabolic outcomes, research on nutritional and gastrointestinal symptoms remains limited. Here we compare clinical data on weight, nutritional disorders and gastrointestinal symptoms of patients before and following one anastomosis gastric bypass (OAGB) and Roux-en-Y gastric Bypass (RYGB).

Materials and Methods

In this retrospective study, data on anthropometry, nutritional indices, dietary intake and gastrointestinal symptoms were retrieved in cohorts of patients up to 2 years following OAGB and RYGB.

Results

Seventy-three patients had either a RYGB (28) or an OAGB (45), with 71% seeking these as a revisional procedure. Significant and higher weight loss was observed in the OAGB cohort at 1 year (%TWL 33.0 ± 8.5 vs. 26.6 ± 12.4), albeit comparable at 2 years postoperatively (%TWL 29.0 ± 11.1 vs. 34.1 ± 11.2). Disorders such as vitamin D, active B12, folate, homocystein (Hcy) and hyperparathyroidism were present following both surgeries. Levels of vitamin D, ferritin and total protein significantly worsened over time. Gastrointestinal symptoms of diarrhoea, steatorrhoea and reflux were higher in the OAGB cohort while the RYGB cohort reported more dumping syndrome (DS).

Conclusion

Significant and similar weight loss results are seen following both OAGB and RYGB. Nutritional disorders were common in both cohorts and increased over time. However, the OAGB patients reported more gastrointestinal side effects, which may contribute to poor quality of life and nutritional consequences. Prospective and longer-term studies investigating the nutritional and gastrointestinal health of patients undergoing OAGB is recommended.

Revisional One-Anastomosis Gastric Bypass After Restrictive Index Surgery-a Metaanalysis and Comparison with Revisional Roux-en-Y Gastric Bypass

BACKGROUND

One-anastomosis gastric bypass (OAGB) was established as a recognized bariatric procedure in the 2018 International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) position statement. This study evaluates the outcomes of revisional OAGB (rOAGB) after a restrictive index procedure, and to compare it to revisional RYGB (rRYGB).

METHODS

A literature search was performed according to the PRISMA guidelines on papers published from inception till February 2020. Original studies involving patients who underwent rOAGB after a primary failed restrictive procedure were included. The primary outcome measured was postrOAGB weight loss. Secondary outcome measures include comorbidity resolution, operative duration, length of stay, morbidity, and mortality.

RESULTS

A total of 21 studies with 1377 patients were included. Five studies compared rOAGB versus rRYGB. Majority of the patients (76%) were female, with mean age of 43.5 years old. Mean body mass index (BMI) before revisional surgery was 41.6 kg/m². The most common biliopancreatic limb length was 200 cm. Percentage of excess weight loss after rOAGB increases to a maximum of 76.0% at 48 months postsurgery. rOAGB resulted in a pooled prevalence of diabetes, hypertension, hyperlipidemia, and obstructive sleep apnea resolution of 74.9%, 48.4%, 63.2%, and 75.7% respectively. When compared to rRYGB, rOAGB demonstrated greater weight loss, comparable metabolic syndrome resolution, but with a shorter operating time. Morbidity and mortality rates were low across all studies.

CONCLUSIONS

rOAGB has potential as an alternative revisional surgery, with weight loss profiles and rates of metabolic syndrome resolution that are comparable to rRYGB.

From the Knife to the Endoscope-a History of Bariatric Surgery

PURPOSE OF REVIEW

Current bariatric surgical practice has developed from early procedures, some of which are no longer routinely performed. This review highlights how surgical practice in this area has developed over time.

RECENT FINDINGS

This review outlines early procedures including jejuno-colic and jejuno-ileal bypass, initial experience with gastric bypass, vertical banded gastroplasty and biliopancreatic diversion with or without duodenal switch. The role laparoscopy has played in the widespread utilization of surgery for treatment of obesity will be described, as will the development of procedures which form the mainstay of current bariatric surgical practice including gastric bypass, sleeve gastrectomy and adjustable gastric banding. Endoscopic therapies for the treatment of obesity will be described. By outlining how bariatric surgical practice has developed over time, this review will help practicing surgeons understand how individual procedures have evolved and also provide insight into potential future developments in this field.

Laparoscopic Roux-En-Y gastric bypass versus one anastomosis (loop) gastric bypass for obesity: A prospective comparative study of weight loss and complications

Introduction

Most Bariatric units perform Laparoscopic Roux-en-Y Gastric Bypass (LRYGB) and One Anastomosis Gastric Bypass (OAGB) for weight loss and metabolic purposes with satisfactory results and low complication profile.

Objectives

This study compares LRYGB and OAGB outcomes in a high volume single bariatric unit.

Methods

Data was collected prospectively and analysed retrospectively for all LRYGB and OAGB performed between Jan 2014 to Dec 2016. The follow up period was for 2 years. Patients who were lost to follow up or had prior bariatric procedure were excluded. Excess weight loss percentage (EWL %), total weight loss percentage (TWL %) and post-operative complications were compared in both groups.

Results

1268 procedures performed. 113 patients were excluded. At 2 years, for LRYGB and OAGB groups mean TWL % was 31% and 35.4% respectively (P < 0.0001); and mean EWL % was 70.1% and 74.8% respectively (P = 0.0119). Gastroesophageal reflux symptoms were higher in OAGB group 17 (8.5%), with 7 patients needing further surgery, versus 26 (2.7%) in LRYGB (P = 0.0003). There was no difference in incidence of marginal ulcers between LRYGB and OAGB 2.7% vs 5% respectively (P = 0.1115). Internal hernia was seen only in LRYGB patients, 22 (2.2%). There was no significant difference in the re-operation rates following LRYGB 52 (5.4%) and OAGB 16 (8%) (P = 0.1824).

Conclusion

OAGB had superior short-term weight loss and low complications profile. Both procedures demonstrated no difference in either marginal ulcers or re-operation rates. Reflux symptoms have remained a major side effect of OAGB.

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One anastomosis gastric bypass has shown to have a safe operative profile and effective weight loss outcomes.

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No difference in marginal ulcerations or reoperation rate between One anastomosis gastric bypass and Laparoscopic Roux en y.

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We recommend strict selection criteria for patient undergoing OAGB.