Outcomes of the One Anastomosis Gastric Bypass with Various Biliopancreatic Limb Lengths: a Retrospective Single-Center Cohort Study

Metabolic outcomes in obese mice undergoing one-anastomosis gastric bypass (OAGB) with a long or a short biliopancreatic limb

One-anastomosis gastric bypass (OAGB) has gained importance as a simple, safe, and effective operation to treat morbid obesity. We previously found that Roux-en-Y gastric bypass surgery with a long compared with a short biliopancreatic limb (BPL) leads to improved weight loss and glucose tolerance in obese mice. However, it is not known whether a long BPL in OAGB surgery also results in beneficial metabolic outcomes. Five-week-old male C57BL/6J mice fed a high-fat diet (HFD) for 8 weeks underwent OAGB surgery with defined BPL lengths (5.5 cm distally of the duodenojejunal junction for short and 9.5 cm for long BPL), or sham surgery combined with caloric restriction. Weight loss, glucose tolerance, obesity-related comorbidities, endocrine effects, gut microbiota, and bile acids were assessed. Total weight loss was independent of the length of the BPL after OAGB surgery. However, a long BPL was associated with lower glucose-stimulated insulin on day 14, and an improved glucose tolerance on day 35 after surgery. Moreover, a long BPL resulted in reduced total cholesterol, while there were no differences in the resolution of metabolic dysfunction-associated steatotic liver disease (MASLD) and adipose tissue inflammation. Tendencies of an attenuated hypothalamic-pituitary-adrenal (HPA) axis and aldosterone were present in the long BPL group. With both the short and long BPL, we found an increase in primary conjugated bile acids (pronounced in long BPL) along with a loss in bacterial Desulfovibrionaceae and Erysipelotrichaceae and simultaneous increase in Akkermansiaceae, Sutterellaceae, and Enterobacteriaceae. In summary, OAGB surgery with a long compared with a short BPL led to similar weight loss, but improved glucose metabolism, lipid, and endocrine outcomes in obese mice, potentially mediated through changes in gut microbiota and related bile acids. Tailoring the BPL length in humans might help to optimize metabolic outcomes after bariatric surgery.NEW & NOTEWORTHY Weight loss following OAGB surgery in obese mice was not influenced by BPL length, but a longer BPL was associated with improved metabolic outcomes, including glucose and lipid homeostasis. These changes could be mediated by bile acids upon altered gut microbiota. Further validation of these findings is required through a randomized human study.

Technical Variations and Considerations around OAGB in IFSO-APC and IFSO-MENAC Chapters, an Expert Survey

OBJECTIVE

This study aimed to evaluate the technical variations of one-anastomosis gastric bypass (OAGB) among IFSO-APC and MENAC experts.

BACKGROUND

The multitude of technical variations and patient selection challenges among metabolic and bariatric surgeons worldwide necessitates a heightened awareness of these issues. Understanding different perspectives and viewpoints can empower surgeons performing OAGB to adapt their techniques, leading to improved outcomes and reduced complications.

METHODS

The scientific team of IFSO-APC, consisting of skilled bariatric and metabolic surgeons specializing in OAGB, conducted a confidential online survey. The survey aimed to assess technical variations and considerations related to OAGB within the IFSO-APC and IFSO-MENAC chapters. A total of 85 OAGB experts participated in the survey, providing their responses through a 35-question online format. The survey took place from January 1, 2024, to February 15, 2024.

RESULTS

Most experts do not perform OAGB for children and adolescents younger than 18 years. Most experts create the gastric pouch over a 36-40-F bougie and prefer to create a gastrojejunostomy, at the posterior wall of the gastric pouch. An anti-reflux suture during OAGB is performed in all patients by 51.8% of experts. Most experts set a common limb length of > 4 m in revisional and conversional OAGBs to prevent nutritional complications.

CONCLUSION

The ongoing debate among metabolic and bariatric surgeons regarding the technical variations and patient selection in OAGB remains a significant point of discussion. This survey demonstrated the variations in technical aspects and patient selection for OAGB among MBS surgeons in the IFSO-APC and IFSO-MENAC chapters. Standardizing the OAGB technique is crucial to ensure optimal safety and efficacy in this procedure.

Prevention of malnutrition after one anastomosis gastric bypass: value of the common channel limb length

PURPOSE

Hypoalbuminemia and anemia are commonly observed indications for one anastomosis gastric bypass (OAGB) reversal and remain significant concerns following the procedure. Sufficient common channel limb length (CCLL) is crucial to minimize nutritional complications. However, limited literature exists regarding the impact of CCLL on OAGB outcomes. This study aimed to assess the effect of CCLL on weight loss and nutritional status in patients who underwent OAGB.

METHODS

A prospective cohort study was conducted from August 2021 to July 2022, involving 64 patients with a body mass index of 40-50 kg/m2. The standardized length of the biliopancreatic limb (BPLL) for all patients in this study was set at 175 cm. Additionally, the measurement of the common channel limb length (CCLL) was performed consistently by the same surgeon for all included patients.

RESULTS

The mean age and BMI of the patients were 39.91 ± 10.03 years and 43.13 ± 2.43 kg/m2, respectively, at the time of surgery. There was a statistically significant negative correlation between CCLL and percent total weight loss (%TWL) at the 12-month mark after OAGB (P = 0.02). Hypoalbuminemia was observed in one patient (1.6%), while anemia was present in 17 patients (26.6%) at the one-year follow-up. Statistical analysis revealed no significant difference in the incidence of anemia and hypoalbuminemia between patients with CCLL < 4 m and those with CCLL ≥ 4 m.

CONCLUSION

A CCLL of 4 m does not appear to completely prevent nutritional complications following OAGB. However, maintaining a CCLL of at least 4 m may be associated with a reduced risk of postoperative nutritional deficiencies.

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.

One Anastomosis Gastric Bypass (OAGB) with a 150-cm Biliopancreatic Limb (BPL) Versus a 200-cm BPL, a Systematic Review and Meta-analysis

This is a systematic review and meta-analysis that assessed the impact of performing OAGB with a 150-cm BPL versus a 200-cm BPL concerning weight loss, comorbidities remission, and adverse nutritional effects. The analysis included studies that compared patients who underwent OAGB with a 150-cm BPL and 200-cm BPL. Eight studies were eligible for this review after searching in the EMBASE, PubMed central database, and Google scholar. The pooled analysis revealed favoring the 200-cm BPL limb length for weight loss, with a highly significant difference in the TWL% (p=0.009). Both groups showed comparable comorbidities remission. Significantly higher ferritin and folate deficiency rates were found in the 200-cm BPL group. Considering a 200-cm BPL when performing OAGB delivers a better weight loss outcome than a 150-cm BPL, which is at the expense of a more severe nutritional deficiency. No significant differences were found regarding the comorbidities' remission.

How accurate is the visual estimation of bowel length by endoscopic surgeons?

Background

Measurement of small bowel length is an essential step in performing bariatric surgery. Surgeons need to measure bowel length in order to create alimentary and biliopancreatic limbs. Inaccurate bowel measurement may affect the outcome of surgery. However, it is not clear how accurate the measurement of bowel length is by surgeons.

Methods

Two image quizzes marking certain lengths of jejunum were sent to participants. They were asked to estimate the length of marked bowels in maze quizzes. The Error of estimation, prevalence of significant error (error greater than 30 percent of actual length), and the relationship between different participant characteristics was investigated.

Results

A total of 86 participants answered the questionnaire. The mean error of estimation was 4.62 cm (27%). Twenty-eight participants (33%) had significant errors in estimation of bowel length.

Conclusion

While there are surgeons that can estimate bowel length with decent accuracy, significant errors in estimation of bowel length are not uncommon among surgeons. Surgeons should consider adopting techniques for accurate measurement of the small intestine.

Predictors for weight loss after Roux-en-Y gastric bypass: the trend and associated factors for weight loss

BACKGROUND

Historically, Roux-en-Y gastric bypass (RYGB) has been considered the gold standard of bariatric surgery (BS). This procedure acts as a mixed restrictive and malabsorptive operation.

METHODS

 This retrospective cohort study included 410 morbidly obese patients (BMI > 40 kg/m2 or BMI > 35 kg/m2 along with at least one major comorbidity) who underwent primary laparoscopic RYGB surgery from 2009 to 2015 by a single surgery team. The patients were 18 years and older with at least 12 months of follow-up. Total weight loss (%TWL) and comorbidity resolution were compared in short-term (12 months) and mid-term (12-60 months) follow-ups. The primary and secondary outcomes were evaluating the effect of Roux-en-Y on weight loss and control of comorbidities, respectively.

RESULTS

 The mean ± SD age, weight, and BMI at surgery were 40.1 ± 10.58 years, 123.32 ± 19.88 kg, and 45.78 ± 5.54 kg/m2, respectively, and 329 (80%) were female, and 62 (15%) had T2DM. %TWL was significantly higher in T2DM patients 9 months postoperatively and after that. Patients with lower BMI (< 50 kg/m2) at surgery and non-diabetic patients had a significantly lower %TWL over a short- and long-term follow-up (P < 0.001).

CONCLUSIONS

BS remains the most efficacious and durable weight loss treatment. However, a proportion of patients will experience insufficient weight loss following BS.

150-cm Versus 200-cm Biliopancreatic Limb One-Anastomosis Gastric Bypass: Propensity Score-Matched Analysis

BACKGROUND

It has been suggested that shortening the length of the biliopancreatic limb (BPL) to 150 cm in one anastomosis gastric bypass (OAGB) would reduce nutritional complication rates without impairing weight loss outcomes. The aim of this study is to compare patients who underwent OAGB with a 200-cm BPL (OAGB-200) to patients with OAGB with a 150-cm BPL (OAGB-150) in terms of weight loss and late morbidity.

METHODS

This is a monocentric retrospective matched cohort study including patients with a body mass index between 35 and 50 kg/m² who underwent an OAGB-150 or an OAGB-200. Patients were matched 1:1 based on age, sex, and body mass index, prior to bariatric surgery.

RESULTS

In total, 784 patients who underwent OAGB were included (OAGB-150 n = 392 and OAGB-200 (n = 392). There was no significant difference in terms of early morbidity. Regarding late morbidity in patients with an OAGB-150, significantly lower rates for marginal ulcer (OR = 0.4, CI 95% [0.2; 0.8], p = 0.006), incisional hernia (OR = 0.5, CI 95% [0.3; 1], p = 0.041), and bowel obstruction (OR = 0.3, CI 95% [0.1; 0.9], p = 0.039) were reported. Likewise, regarding late nutritional deficiencies, post-OAGB-150, a significantly lower number of patients with hypoalbuminemia (OR = 0.3, CI 95% [0.2; 0.7], p = 0.006), low vitamin B9 (OR = 0.5, CI 95% [0.2; 1], p = 0.044), and low ferritin (OR = 0.5, CI 95% [0.3; 0.8], p = 0.005) were observed. There was no significant difference in the percentage of excess BMI loss at 1, 2, 3, 4, and 5 years.

CONCLUSION

Compared to OAGB-200 in patients with BMI ≤ 50 kg/m², OAGB-150 results in fewer nutritional deficiency rates long term, without impairing weight loss.

What Is the Efficacy of Short Length of Biliopancreatic Limb in One-Anastomosis Gastric Bypass? A Systematic Review and Meta-analysis of Short-Term Results

OBJECTIVE

To systematically review the efficacy of short length of biliopancreatic limb (BPL) in laparoscopic one anastomosis gastric bypass (OAGB).

METHODS

By thoroughly investigating in PubMed, Embase, and the Cochrane Library, each research containing the comparison between short BPL and 200-cm BPL was included, inception in July 2021. The research followed the guidance of Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) recommendations.

RESULT

A total of 1288 patients were included for meta-analysis. Results showed that in the short term, compared with 200-cm BPL, percentage excess weight loss (%EWL) did not show significant reduction (p = 0.91), neither did the incidence of vitamin D deficiency (p = 0.87) nor hypoalbuminemia (p = 0.06), while percentage total weight loss (%TWL) was significantly higher in the 200-cm BPL group (p = 0.0005). At 1, 2, and 8 years postoperatively, patients with short BPL still obtained significantly reduced body mass index (BMI).

CONCLUSION

Short BPL shows significant effect of weight loss; however, it seems no significantly lower rates of adverse events in the short term are found. More research with randomized controlled design is encouraged to further address the incidence of adverse events in the long term.

Tailoring limb length based on total small bowel length in one anastomosis gastric bypass surgery (TAILOR study): study protocol for a randomized controlled trial

Background

The one anastomosis gastric bypass (OAGB) is being performed by an increasing number of bariatric centers over the world. However, the optimal length of the biliopancreatic (BP) limb remains a topic of discussion. Retrospective studies suggest the benefit of tailoring BP-limb length; however, randomized trials are lacking. The aim of this study is to investigate whether tailoring the length of the BP-limb based on total small bowel length (TSBL) leads to better results in terms of weight loss, vitamin deficiencies, and bowel movements compared to a fixed BP-limb length.

Methods

The TAILOR study is a double-blind single-center randomized controlled trial. Patients scheduled for primary OAGB surgery will be randomly allocated either to a standard BP-limb of 150 cm or to a BP-limb length based on their TSBL: TSBL < 500 cm, BP-limb 150 cm; TSBL 500–700 cm, BP-limb 180 cm; TSBL > 700 cm, BP-limb 210 cm. The primary outcome is to compare the percent total weight loss (%TWL) at 5 years between the two groups. Secondary outcomes include nutritional deficiencies, remission of comorbidities, symptoms of dumping, quality of life, and daily bowel movements. The study includes a total of 212 patients and is designed to detect a 5% difference in the primary endpoint.

Discussion

The TAILOR study will provide new insights into the effect of different BP-limb lengths and the role of the TSBL in the OAGB. The study is designed to provide guidance for bariatric surgeons to determine the optimal BP-limb length in the OAGB.

Trial registration

Dutch Trial Register NL7945. Prospectively registered on 08 September 2019. NTR (trialregister.nl)

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06456-w.