|Year : 2022 | Volume
| Issue : 1 | Page : 10-15
Gastric bypass: Historical evolution and technical development of a time-honored bariatric procedure
Eduardo Lemos de Souza Bastos1, Dênis Pajecki2
1 Department of Gastrointestinal Surgery, Marilia School of Medicine, Brazil
2 Metabolic and Bariatric Unit, University of São Paulo, Brazil
|Date of Submission||13-Dec-2021|
|Date of Acceptance||11-Jan-2022|
|Date of Web Publication||09-Mar-2022|
Prof. Eduardo Lemos de Souza Bastos
Department of Gastrointestinal Surgery, Marilia School of Medicine, Marilia
Source of Support: None, Conflict of Interest: None
Gastric bypass (GB) was originally described over 50 years ago as an alternative to jejunoileal bypass in the surgical approach to morbid obesity. Since then, several technical improvements and modifications have been proposed over time to simplify technical execution, enhance outcomes, and minimize the risk of complications and/or adverse effects. After half a century of robust and sustained results, the technical drawing of the GB still undergoes improvements, mainly to ensure even more safety for obese patients and encompass modern concepts of metabolic surgery. This review aims to outline the main technical changes proposed for GB from its original description to the current times.
Keywords: Bariatric Surgery, Gastric Bypass, History, Morbid Obesity
|How to cite this article:|
Bastos EL, Pajecki D. Gastric bypass: Historical evolution and technical development of a time-honored bariatric procedure. J Bariatr Surg 2022;1:10-5
|How to cite this URL:|
Bastos EL, Pajecki D. Gastric bypass: Historical evolution and technical development of a time-honored bariatric procedure. J Bariatr Surg [serial online] 2022 [cited 2022 May 21];1:10-5. Available from: http://www.jbsonline.org/text.asp?2022/1/1/10/339263
| Introduction|| |
Obesity is a chronic, multifactorial, and incurable disease with increasing incidence and prevalence, especially in countries with a western lifestyle.,, Although dietary control, regular physical activities, and/or drug therapy have been considered the first line of therapeutic approach, bariatric and metabolic surgery is the most effective approach for patients with higher body mass index (BMI) and/or with associated comorbidities, such as type 2 diabetes, hypertension, sleep apnea, and dyslipidemia. Studies comparing clinical and surgical treatment in morbidly obese individuals have shown better results in short, medium, and longterm in favor of the surgical approach, both in relation to sustained weight loss and control of comorbidities, as well as in the reduction of macro- and microvascular events and mortality.,,,,
Several techniques are available in the current surgical armamentarium, and despite the exponential growth of laparoscopic sleeve gastrectomy (LSG) in recent years, Roux-en-Y gastric bypass (RYGB) is still considered by many surgeons as their preferred technique and remains outperforming LSG in some countries.,
Gastric bypass (GB) was first described as a mainly restrictive bariatric procedure shortly after the era of jejunoileal bypass (JIB). Since then, several technical changes and improvements have been proposed, resulting in the current concept of a small vertical gastric pouch based on lesser curvature, narrow gastrojejunostomy, and Roux-en-Y reconstruction with longer limbs. As the GB still remains in the spotlight as a bariatric and metabolic procedure and will probably remain so for a longer time, it is quite opportune to know the main technical changes proposed over time that ended up resulting in the current technical drawing.
Thus, this narrative review was conducted to outline the historical evolution and technical development of GB, highlighting the most striking technical changes since the beginning.
| Early Reports as an Essentially Restrictive Gastric Procedure|| |
GB was originally described in 1967 by Edward Eaton Mason and Chikashi Ito as a result of efforts to find an effective operation for the treatment of morbid obesity without adverse effects commonly observed in the JIB. In fact, the concept of GB was derived from observation of weight loss after subtotal gastrectomy, but gastric resection was seen as too “radical and irreversible” to be considered as a feasible surgical option in patients without a “specific gastric disease.” Thus, GB was born to mimic the expected postgastrectomy weight loss, except that nothing would be removed. After experiments in dogs to assess the effect on body weight and possible occurrence of a peptic ulcer due to the “retained antrum,” the outcomes of gastric exclusion in eight morbidly obese patients were originally reported, and the operation was called “Gastric Bypass.” Interestingly, the first patient who underwent this operation in 1966 did not have morbid obesity per se as a primary indication but rather the weight loss necessary to minimize the risk of recurrence in a planned incisional hernia repair due to previous appendectomy. The surgical technique was based on a horizontal gastric division, excluding about 80% of the stomach distally. The proximal gastric pouch consisted basically of the fundus and was end-to-side anastomosed to a jejunal loop about 60 cm from the angle of Treitz, which was carried to the supramesocolic field via antecolic pathway. Thus, reconstruction of alimentary transit in the original description of GB was Billroth-II type, with wide gastrojejunostomy (polya anastomosis-i. e., oralis-totalis) and short afferent loop.
Two years later, in 1969, the same authors published their personal experience in a slightly larger series (n = 24) and reported some technical modifications. Gastric exclusion increased to about 90%, thereby reducing pouch size. Reconstruction of alimentary transit remained through an end-to-side gastrojejunostomy (Billroth-II type), but the jejunal loop now reached the supramesocolic field via retrocolic pathway and the Treitz ligament section was recommended to allow an even shorter afferent loop. In addition, gastrojejunostomy was performed in the greater curvature by oralis-partialis technique, therefore with a smaller diameter (about 2–3 cm). The authors also emphasized that it would be essential to attach the borders of the transverse mesocolon opening to the gastric pouch walls to avoid twisting and jejunal stasis, and strongly recommended that the proximal portion of the excluded stomach be attached to the anterior pouch wall to also prevent the stasis of gastric secretions.
In 1973, Mason et al. reported their observations on the entire cohort of patients undergoing GB since 1966 (n = 130) in a comparative study between GB (n = 49) and horizontal gastroplasty (n = 42). Apparently, the overall technical drawing remained unchanged, but a narrower gastrojejunostomy was reported (1.5–2 cm). After two years, in 1975, Mason et al. again reported personal observations and results from this cohort of patients, but now in a larger series (n = 377). Although the idea of the horizontal pouch and Billroth-II reconstruction remained unchanged, the authors emphasized the need for an even narrower gastrojejunostomy (around 1.2 cm) and proposed two different ways of constructing the gastric pouch, both still horizontal. In this publication, it included 17 patients who underwent GB as revisional surgery after horizontal gastroplasty.
| From Billroth-II to Roux-en-Y Reconstruction|| |
In 1977, 10 years after the original publication, two studies reported relevant technical changes in the design proposed by Mason and Ito, both in comparative studies between GB and JIB. Alden et al. performed gastric exclusion and pouch construction by means of a noncutting horizontal stapling, therefore without gastric division. In addition, calibrated gastrojejunostomy (2 cm) was performed using linear stapler. These two modifications were considered by the authors as “technical simplification.” Also in 1977, Griffen et al. published a new proposal for alimentary reconstruction in GB, from Billroth-II to Roux-en-Y. The arguments to support this technical change were to make the gastrojejunostomy an easier maneuver and to minimize the occurrence of postoperative biliary vomiting, although the length of alimentary limb (Roux limb) was pretty short (30 cm). This proposal was gradually accepted by surgeons until it became standard.
| Pouch Shape and Placement of the Restriction Ring: The Fobi Pouch|| |
In 1983, Torres et al. proposed a vertical gastric pouch built from the angle of His toward the lesser gastric curvature, where a calibrated (10 mm) gastrojejunostomy was positioned. As gastric dissection for the pouch construction was performed from the lesser curvature through the opening of the gastrohepatic ligament, without approaching the greater curvature, there were no risks of vascular and splenic injuries. In addition, a smaller pouch (20–35 ml) excluding approximately 97% of the stomach was reached. The gastrojejunostomy was technically easier, performed in a region with better blood supply, and the gastric outlet remained practically in continuation with the esophagus. Vertical orientation in the pouch construction from the lesser gastric curvature was gradually accepted among bariatric surgeons until it became the standard.
In 1989, Fobi et al. began to recommend placing a 5.5 mm restriction ring around a triangular-shaped pouch to enhance the restrictive action for solid foods, minimize clinically relevant episodes of dumping syndrome, and prevent long-term weight recovery due to gastrojejunostomy enlargement, trying to gather Mason's vertical banded gastroplasty and RYGB benefits previously observed.
Later, when reviewing their own GB experience, Fobi et al. described in detail the surgical technique for the construction of gastric pouch according to the “Fobi-Pouch Operation for Obesity” (“The Transected Silastic Vertical Gastric Bypass”), emphasizing both the need for the placement of the ring and the complete pouch transection. The concept of placing the restriction ring was also supported by better long-term weight loss seen in patients undergoing RYGB as revisional surgery from VBG or Silastic ring vertical gastroplasty surgery whose gastrojejunostomy was performed distally to the band/ring.
In turn, the recommendation for complete pouch transection in the “Fobi-Pouch Operation for Obesity” comes from the early 1990s and derived from the observation that the staple line breakdown was frequently associated with morbidities and reoperations. Moreover, it was also recommended the interposition of a short segment of the Roux limb between the gastric pouch and bypassed stomach to guarantee the maintenance of the gastric division. At the same time, MacLean et al. also resumed the concept of complete gastric pouch transection and named this operation as “Isolated Gastric Bypass.”
The concept of complete transection remains current, since all modern linear staplers used in the pouch construction are also “cutting” type, but the jejunal interposition is no longer widely applied. Conversely, RYGB ringed pouch has remained in force for many years until severe related complications made it virtually obsolete today.
| Fobi-Capella Operation: The Current Technical Drawing|| |
The current generation of RYGB began in the late 1980s and early 1990s with the technical principles proposed by Fobi and Capella et al.,, as a primary treatment of morbid obesity or as a revisional procedure for Mason's VBG. The narrowing of the pouch lumen was recommended in both, either with polypropylene mesh (1.5 cm wide/5.5 cm length) in the initial cases described by Capella (n = 90) or with a 5.5 cm Silastic ring sutured in place with 2-0 polypropylene in the final Capella series (n = 57) and in entire Fobi series (n = 357). The gastric pouch shape was more triangular in the Fobi technique and more rectangular in the Capella technique. In addition, the lengths of the alimentary and biliopancreatic (BLP) limbs were also different, being 100 and 25 cm, respectively, in the Capella technique, and 60 and 60 cm, respectively, in the Fobi technique. At the same time, Fobi also advocated a common channel of 150 cm and the remaining small bowel equally shared between the alimentary and BLP limbs in super-obese patients (i. e., patients with more than 225% of ideal body weight).
Minor differences aside, the techniques proposed by Fobi and Capella were quite similar and the RYGB became known as Fobi-Capella surgery thereafter, mainly in Latin-America.
| Laparoscopic and Robotic Approach|| |
Despite the remarkable improvements until then, a milestone step occurred in 1994 with description of laparoscopic approach by Wittgrove et al., starting a new era not only to RYGB but to bariatric surgery as a whole. The original publication reported the technique applied in five patients, with which the first patient was operated in 1993. The step-by-step was based on open RYGB systematization, with alimentary limb reaching the supramesocolic field via transmesocolic and retrogastric pathway. All anastomoses were strictly stapled, the gastrojejunostomy was performed through 21-mm circular stapler with ogive introduced orally, and gastric pouch was constructed vertically without restriction ring. In 1996, 2 years after its outstanding publication, Wittgrove and Clark published their personal experience with a larger number of patients (n = 75). After 4 years, in 2000, an even larger case series (n = 500) on the laparoscopic approach in GB was published by the same authors. Although some technical alterations were made in these subsequent series, surgical steps were basically maintained. At that time, some key technical features to optimize the effects of laparoscopic RYGB (LRYGB) were highlighted by the authors, namely (1) complete gastric division, (2) lesser curvature-based pouch, minimal pouch size, (3) retrocolic and retrogastric Roux-limb, and (4) calibrated anastomosis. After 20 years, these highlights remain widely applied, perhaps with the exception of the Roux-limb pathway.
In 1996, shortly after Wittgrove's pioneering spirit in the USA, Lonroth et al. reported the European laparoscopic experience started in 1994 with six patients undergoing GB with horizontal pouch, Billroth-II reconstruction, two-layer handsewn gastrojejunostomy and Braun-type enteroanastomosis 20 cm distally from gastrojejunostomy, perhaps to minimize bilious vomiting.
From these original reports in the mid-90s, laparoscopic approach has paid to the attention of bariatric surgeons worldwide. In the late 1990s, Higa et al. contributed significantly to the expansion of LRYGB through a technical standardization that was applied to all eligible patients, regardless of the absolute size of the patient or previous operations. In addition, the use of materials from common videolaparoscopy surgery showed that the length of the instrumentation was not a limiting factor.,
However, LRYGB still followed the concepts and technical steps previously established by open surgery. Thus, the procedures were generally very long and technically demanding, especially for surgeons with scarce experience in videolaparoscopic surgery. Even considering this initial technical challenge, as early as 2003, the percentage of LRYGB surpassed open RYGB (25.67% and 23.07%, respectively). With the main purpose of making the procedure technically easier and more reproducible, thereby shortening the learning curve and reducing operative time and the risk of technical complications, some technical simplifications were subsequently proposed. The “Simplified Gastric Bypass” (or Brazilian technique) proposed by Ramos et al. and “Lönroth technique” proposed by Olbers et al. are two examples of these technical simplifications, both of which are still used today by several surgeons worldwide and in some European centers, respectively.
Both the techniques mentioned above were based on very similar surgical steps. After making the gastric pouch, the intestinal step of the surgery is carried out by the initial construction of a double omega loop, in reference to the Greek letter omega, in capitals. Based on the surgeon's frontal view, the first omega-loop consists of the alimentary limb on the left, the BPL on the right, and the gastrojejunostomy in the center. In the second, the alimentary limb is positioned on the left and the common channel on the right, with the entero–entero-anastomosis in the center. Following this montage, the section of the jejunum between the two anastomoses provides the reconstruction of the food transit in Roux-en-Y fashion. Thus, the surgeon can perform stapling and anastomoses in a single surgical field (supramesocolic), which can be seen as a “technical simplification.”
Aside to these and others technical simplifications, the technological evolution of laparoscopic surgery as a whole along with surgeons' growing expertise in addressing obese patients laparoscopically has resulted in procedures with shorter operative time, faster recovery, and lower complication rates. In addition to the effectiveness observed in the vast majority of cases, these were key factors that drove the expressive growth of LRYGB from the 2000s onward, strongly helping to consolidate it as the preferred technique of most bariatric surgeons around the world. More recently, LRYGB has also been performed using robotic platforms, but without major changes in technical systematization compared to the traditional laparoscopic approach.,
| The One-Anastomosis Gastric Bypass|| |
In 1997, Rutledge started a case series resuming the GB reconstruction with just one gastrojejunostomy, published in 2001 (n = 1,274). The operation was called “Mini-Gastric Bypass” (MGB) to express a technical simplification of the traditional RYGB. Briefly, a laparoscopically long-slender gastric pouch (“sleeve-like”) was made and a single stapled end-to-side gastrojejunostomy about 200 cm distally from the Treitz angle reconstructed the food transit.
Soon after Rutledge's original publication, Carbajo et al. started a case series published in 2005 with data from 209 patients undergoing GB also with reconstruction of the food transit with just one anastomosis. In this first case series, a technical change in the gastrojejunostomy to reduce the time of contact of BLP secretion with the gastric mucosa (“anti-reflux mechanism”) was proposed. This anti-reflux mechanism was described in detail in 2004 and the operation was named “Bypass Gástrico de Una Anastomosis” (BaGUA, in Spanish)., Later, Carbajo et al. proposed another significant change in the technical design of the procedure, where the afferent loop should no longer have a fixed length but tailored according to the total small bowel length and patient's BMI.,,
Since pioneering studies from Rutledge and Carbajo, there has been a growing percentage of one-anastomosis GB (OAGB) referrals, especially in Europe, the Middle East, and some regions in Asia, tending to overtake RYGB soon.,,, In 2018, the IFSO Position Statement regarding MGB-OAGB recognized this surgery as a regular bariatric/metabolic procedure, also recommended that “OAGB” should be the identifier for this procedure in future publications. More recently, the Consensus Conference Statement on OAGB-MGB, endorsed by IFSO, considered that both MGB (proposed by Rutledge) and OAGB (BaGUA, proposed by Carbajo) should be considered in the same class of bariatric/metabolic procedures, regardless of technical differences.
The debate over whether OAGB is just a modality of GB or a different class of bariatric/metabolic procedure is one of the hot topics in bariatric surgery today, and is far from finished.
| Limbs Lengthening: The Concept of Metabolic Effect|| |
Since the late 1980s and early 1990s, some authors began to report longer alimentary and BLP limbs in order to enhance the effect on weight loss in cases of super-obesity or weight loss failure (inadequate weight loss or weight recovery). Since then, this drawing has been called of the “distal RYGB.”,,
Except in these above-mentioned situations, the afferent loop and the alimentary and BLP limbs were usually long enough just to allow the reconstruction of the alimentary transit according to the universal principles already established for Billroth-II and Roux-en-Y gastrectomies, respectively.
From the mid-2000s onward, the spread of anterior (foregut) and posterior (hindgut) theories has supported longer exclusions of the small bowel, mainly to get stronger and longer-lasting metabolic effects, especially on DM2.
Based on the growing concepts of metabolic surgery, some surgeons have started to perform RYGB surgery with the exclusion of an increasing part of the jejunum (over 150–200 cm).,,,,, The “metabolic gastric bypass,” characterized by longer limbs but not as long as in the distal GB, is perhaps the most current major changing in the technical drawing of RYGB. Despite adoption by many surgeons around the world, the vaunted greater effectiveness of longer jejunal exclusions on glucose homeostasis remains to be better clarified in longer-term observations.
| Technical Consensus and Points of Contention|| |
Although GB technical details may depend on the training and experience of the surgeon, (1) laparoscopic approach, (2) small vertical pouch based on lesser curvature, (3) Roux-en-Y reconstruction, and (4) longer limbs appear to be universally accepted today. Conversely, gastric pouch size, restriction ring placement, wide/narrow or stapled/handsewn gastrojejunostomy, intestinal step before or after, transmesocolic or antecolic pathway, length of the alimentary and BLP limbs, closure of the mesenteric spaces, staple-line reinforcement, and drainage of the peritoneal cavity are just some topics that are still under debate. This extensive list of lack of consensus on technical steps shows how much GB still has to evolve.
| One Last Consideration: Is RYGB Now a Misnomer?|| |
A misnomer is when a noun is used inappropriately, not reflecting its real meaning. The original idea of GB was to reduce gastric volume to provoke early satiety with small portions of ingested food, especially solids ones. The exclusion of the duodenum and part of the jejunum was only natural consequence of well-established techniques to alimentary transit reconstruction after partial gastrectomies, such as Billroth-II and Roux-en-Y. Thus, the nomenclatures “Gastric Bypass” at first, and then “Roux en Y Gastric Bypass”, appeared well suited at the time.
At present, the “Gastric Bypass” aims not only to perform gastric exclusion but also of the duodenum and part of the jejunum, clearly featured by the increasing length of the BLP limb. Thereby, the nomenclature “Gastric Bypass” and “Roux-en-Y Gastric Bypass” may no longer faithfully represent the targets of this operation, and perhaps, the most appropriate nomenclature should be “Roux-en -Y gastroduodenojejunal bypass”.
| Conclusion|| |
GB is undoubtedly a time-honored bariatric procedure. Since the beginning of its history, it has been the object of several technical improvements and changes over time, but it has always remained a safe and effective option in the surgical management of obesity and its related comorbidities, regardless of the new procedures that have emerged throughout of these more than 50 years.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Ng M, Fleming T, Robinson M, Thomson B, Graetz N, Margono C, et al.
Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: A systematic analysis for the Global Burden of Disease Study 2013. Lancet 2014;384:766-81.
GBD 2015 Obesity Collaborators; Afshin A, Forouzanfar MH, Reitsma MB, Sur P, Estep K, et al.
Health effects of overweight and obesity in 195 countries over 25 years. N Engl J Med 2017;377:13-27.
NCD Risk Factor Collaboration (NCD-RisC). Trends in adult body-mass index in 200 countries from 1975 to 2014: A pooled analysis of 1698 population-based measurement studies with 19·2 million participants. Lancet 2016;387:1377-96.
Gloy VL, Briel M, Bhatt DL, Kashyap SR, Schauer PR, Mingrone G, et al.
Bariatric surgery versus non-surgical treatment for obesity: A systematic review and meta-analysis of randomised controlled trials. BMJ 2013;347:f5934.
Maciejewski ML, Arterburn DE, Van Scoyoc L, Smith VA, Yancy WS Jr., Weidenbacher HJ, et al.
Bariatric surgery and long-term durability of weight loss. JAMA Surg 2016;151:1046-55.
Schauer PR, Bhatt DL, Kirwan JP, Wolski K, Aminian A, Brethauer SA, et al.
Bariatric surgery versus intensive medical therapy for diabetes – 5-year outcomes. N Engl J Med 2017;376:641-51.
Fisher DP, Johnson E, Haneuse S, Arterburn D, Coleman KJ, O'Connor PJ, et al.
Association between bariatric surgery and macrovascular disease outcomes in patients with type 2 diabetes and severe obesity. JAMA 2018;320:1570-82.
Cohen RV, Pereira TV, Aboud CM, Petry TB, Lopes Correa JL, Schiavon CA, et al.
Effect of gastric bypass vs best medical treatment on early-stage chronic kidney disease in patients with type 2 diabetes and obesity: A randomized clinical trial. JAMA Surg 2020;155:e200420.
Angrisani L, Santonicola A, Iovino P, Vitiello A, Higa K, Himpens J, et al.
IFSO worldwide survey 2016: Primary, endoluminal, and revisional procedures. Obes Surg 2018;28:3783-94.
Mason EE, Ito C. Gastric bypass in obesity. Surg Clin North Am 1967;47:1345-51.
Mason EE, Ito C. Gastric bypass. Ann Surg 1969;170:329-39.
Printen KJ, Mason EE. Gastric surgery for relief of morbid obesity. Arch Surg 1973;106:428-31.
Mason EE, Printen KJ, Hartford CE, Boyd WC. Optimizing results of gastric bypass. Ann Surg 1975;182:405-14.
Alden JF. Gastric and jejunoileal bypass. A comparison in the treatment of morbid obesity. Arch Surg 1977;112:799-806.
Griffen WO Jr., Young VL, Stevenson CC. A prospective comparison of gastric and jejunoileal bypass procedures for morbid obesity. Ann Surg 1977;186:500-7.
Torres JC, Oca CF, Garrison RN. Gastric bypass: Roux-en-Y gastrojejunostomy from the lesser curvature. South Med J 1983;76:1217-21.
Fobi MA, Lee H, Fleming A. The surgical technique of the banded Roux-en-Y gastric bypass. J Obes Wgt Reg 1989;8:99-102.
Fobi MA, Lee H. The surgical technique of the Fobi-Pouch operation for obesity (the transected silastic vertical gastric bypass). Obes Surg 1998;8:283-8.
Mason EE. Vertical banded gastroplasty for obesity. Arch Surg 1982;117:701-6.
Laws HL. Standardized gastroplasty orifice. Am J Surg 1981;141:393-4.
Fobi MA, Lee H. SILASTIC ring vertical banded gastric bypass for the treatment of obesity: Two years of follow-up in 84 patients. J Natl Med Assoc 1994;86:125-8.
MacLean LD, Rhode BM, Sampalis J, Forse RA. Results of the surgical treatment of obesity. Am J Surg 1993;165:155-60.
Capella RF, Capella JF, Mandec H, Nath P. Vertical banded gastroplasty-gastric bypass: Preliminary report. Obes Surg 1991;1:389-95.
Fobi M. Why the operation i prefer is silastic ring vertical gastric bypass. Obes Surg 1991;1:423-6.
Wittgrove AC, Clark GW, Tremblay LJ. Laparoscopic gastric bypass, roux-en-Y: Preliminary report of five cases. Obes Surg 1994;4:353-7.
Wittgrove AC, Clark GW, Schubert KR. Laparoscopic gastric bypass, Roux-en-Y: Technique and results in 75 patients with 3-30 months follow-up. Obes Surg 1996;6:500-4.
Wittgrove AC, Clark GW. Laparoscopic gastric bypass, Roux-en-Y- 500 patients: Technique and results, with 3-60 month follow-up. Obes Surg 2000;10:233-9.
Lönroth H, Dalenbäck J, Haglind E, Lundell L. Laparoscopic gastric bypass. Another option in bariatric surgery. Surg Endosc 1996;10:636-8.
Higa KD, Boone KB, Ho T, Davies OG. Laparoscopic Roux-en-Y gastric bypass for morbid obesity: Technique and preliminary results of our first 400 patients. Arch Surg 2000;135:1029-33.
Higa KD, Boone KB, Ho T. Complications of the laparoscopic Roux-en-Y gastric bypass: 1,040 patients – What have we learned? Obes Surg 2000;10:509-13.
Buchwald H, Williams SE. Bariatric surgery worldwide 2003. Obes Surg 2004;14:1157-64.
Ramos AC, Silva AC, Ramos MG, Canseco EG, Galvão-Neto Mdos P, Menezes Mde A, et al.
Simplified gastric bypass: 13 years of experience and 12,000 patients operated. Arq Bras Cir Dig 2014;27 Suppl 1:2-8.
Olbers T, Lönroth H, Fagevik-Olsén M, Lundell L. Laparoscopic gastric bypass: Development of technique, respiratory function, and long-term outcome. Obes Surg 2003;13:364-70.
Ramos AC, Domene CE, Volpe P, Pajecki D, D'Almeida LA, Ramos MG, et al.
Early outcomes of the first Brazilian experience in totally robotic bariatric surgery. Arq Bras Cir Dig 2013;26 Suppl 1:2-7.
Rogula T, Koprivanac M, Janik MR, Petrosky JA, Nowacki AS, Dombrowska A, et al.
Does robotic Roux-en-Y gastric bypass provide outcome advantages over standard laparoscopic approaches? Obes Surg 2018;28:2589-96.
Rutledge R. The mini-gastric bypass: Experience with the first 1,274 cases. Obes Surg 2001;11:276-80.
García-Caballero M, Carbajo M. One anastomosis gastric bypass: A simple, safe and efficient surgical procedure for treating morbid obesity. Nutr Hosp 2004;19:372-5.
Carbajo M, García-Caballero M, Toledano M, Osorio D, García-Lanza C, Carmona JA. One-anastomosis gastric bypass by laparoscopy: Results of the first 209 patients. Obes Surg 2005;15:398-404.
Garciacaballero M, Reyes-Ortiz A, García M, Martínez-Moreno JM, Toval JA, García A, et al.
Changes of body composition in patients with BMI 23-50 after tailored one anastomosis gastric bypass (BAGUA): Influence of diabetes and metabolic syndrome. Obes Surg 2014;24:2040-7.
Carbajo MA, Luque-de-León E, Jiménez JM, Ortiz-de-Solórzano J, Pérez-Miranda M, Castro-Alija MJ. Laparoscopic one-anastomosis gastric bypass: Technique, results, and long-term follow-up in 1200 patients. Obes Surg 2017;27:1153-67.
Deitel M. History of the MGB and OAGB operations. Int J Surg 2019;66:79-83.
Haddad A, Fobi M, Bashir A, Al Hadad M, ElFawal MH, Safadi B, et al.
Outcomes of one anastomosis gastric bypass in the IFSO Middle East North Africa (MENA) region. Obes Surg 2019;29:2409-14.
Welbourn R, Hollyman M, Kinsman R, Dixon J, Liem R, Ottosson J, et al.
Bariatric surgery worldwide: Baseline demographic description and one-year outcomes from the fourth IFSO global registry report 2018. Obes Surg 2019;29:782-95.
De Luca M, Tie T, Ooi G, Higa K, Himpens J, Carbajo MA, et al.
Mini Gastric Bypass-One Anastomosis Gastric Bypass (MGB-OAGB)-IFSO position statement. Obes Surg 2018;28:1188-206.
Ramos AC, Chevallier JM, Mahawar K, Brown W, Kow L, White KP, et al.
IFSO (International Federation for Surgery of Obesity and Metabolic Disorders) Consensus Conference Statement on One-Anastomosis Gastric Bypass (OAGB-MGB): Results of a modified delphi study. Obes Surg 2020;30:1625-34.
Torres J, Oca C. Gastric bypass lesser curvature with distal Roux-en-Y. Bariatric Surg 1987;5:10-5.
Brolin RE, Kenler HA, Gorman JH, Cody RP. Long-limb gastric bypass in the superobese. A prospective randomized study. Ann Surg 1992;215:387-95.
Pinheiro JS, Schiavon CA, Pereira PB, Correa JL, Noujaim P, Cohen R. Long-long limb Roux-en-Y gastric bypass is more efficacious in treatment of type 2 diabetes and lipid disorders in super-obese patients. Surg Obes Relat Dis 2008;4:521-5.
Nora M, Guimarães M, Almeida R, Martins P, Gonçalves G, Freire MJ, et al.
Metabolic laparoscopic gastric bypass for obese patients with type 2 diabetes. Obes Surg 2011;21:1643-9.
Kaska L, Kobiela J, Proczko M, Stefaniak T, Sledziński Z. Does the length of the biliary limb influence medium-term laboratory remission of type 2 diabetes mellitus after Roux-en-Y gastric bypass in morbidly obese patients? Wideochir Inne Tech Maloinwazyjne 2014;9:31-9.
Nergaard BJ, Leifsson BG, Hedenbro J, Gislason H. Gastric bypass with long alimentary limb or long pancreato-biliary limb – Long-term results on weight loss, resolution of co-morbidities and metabolic parameters. Obes Surg 2014;24:1595-602.
Murad AJ Jr., Cohen RV, de Godoy EP, Scheibe CL, Campelo GP, Ramos AC, et al.
prospective single-arm trial of modified long biliopancreatic and short alimentary limbs Roux-En-Y gastric bypass in type 2 diabetes patients with mild obesity. Obes Surg 2018;28:599-605.
Miras AD, Kamocka A, Tan T, Pérez-Pevida B, Chahal H, Moorthy K, et al
. Long Limb Compared with Standard Limb Roux-en-Y Gastric Bypass for Type 2 Diabetes and Obesity: The LONG LIMB RCT. Southampton (UK): NIHR Journals Library; 2021.