Long limb Roux en Y gastric bypass revisited

Roux-en-Y gastric bypass (RYGB) that is performed with at least a 150-cm Roux limb results in significantly greater weight loss than shorter (<100-cm) Roux limb procedures in superobese patients(BMI >50 kg/m2). Conversely, longer Roux limb procedures do not provide greater weight loss in less obese (BMI <50 kg/m2)patients. Modest elongation of the Roux limb-in the range of 150 cm to 200 cm-does not result in more frequent nutritional sequelae compared with shorter Roux limb procedures. This article discusses the current status of long limb Roux-en-Y gastric bypass in the context of weight loss, metabolic sequelae and CPT coding.     

Relationship between varying Roux limb lengths and weight loss in gastric bypass

BACKGROUND: The optimal Roux limb length for gastric bypass is unknown. Therefore, the effect of Roux limb length on weight loss and nutritional deficiency after a Roux-en-Y gastric bypass procedure was studied. METHODS: From September 2000 to February 2004, 165 Roux-en-Y gastric bypass surgeries were performed at William Beaumont Army Medical Center. One-year follow-ups were completed on 97 patients. Roux limbs varied from 100 cm to 150 cm, based on the patient's body mass index (BMI). Roux limb lengths were compared with 1-year changes in absolute weight, BMI, and nutritional levels. RESULTS: In the 97 patients, average age at the time of surgery was 44 years (range, 20-63). Average BMI was 46.7 +/- 6.6 kg/m(2) before surgery and 30.9 +/- 5.8 kg/m(2) at 1-year follow-up. Average absolute weight loss at 1 year was 43.7 +/- 12.8 kg. A statistically significant linear relationship existed between Roux limb length and reductions in BMI and absolute weight. No relationship existed between Roux limb length and changes in nutrient levels. CONCLUSION: A linear relationship exists between Roux limb length and 1-year weight loss.     

Roux limb obstruction secondary to constriction at transverse mesocolon rent after laparoscopic Roux-en-Y gastric bypass

BackgroundPartial small bowel obstruction can occur as a result of circumferential extrinsic compression of the Roux limb as it traverses the transverse mesocolic rent from thickened cicatrix formation in this area. The aim of this study is to examine the incidence of Roux limb compression with particular attention to the timing of presentation and associated weight loss in the setting of a university hospital in the United States.MethodsA retrospective chart review was performed of all patients undergoing laparoscopic Roux-en-Y gastric bypass who developed symptomatic small bowel obstruction requiring operative intervention from January 1, 2000 and September 15, 2006.ResultsOf 2215 patients, 20 (.9%) developed symptomatic Roux limb compression. The mean time to presentation was 48 days after LRYGB. By this stage, the mean percentage of excess body weight loss was 29%. Of the 20 patients, 19 underwent an upper gastrointestinal contrast study, the results of which confirmed the diagnosis. In all cases, laparoscopic intervention was successful in freeing the constricted Roux limb by dividing the cicatrix formation between the Roux limb and mesocolic window. Switching from continuous to interrupted closure of the space between Roux limb and mesocolic window appeared to reduce the incidence of this complication (P <.05).ConclusionNarrowing at the transverse mesocolon rent is an uncommon cause of small bowel obstruction after retrocolic laparoscopic Roux-en-Y gastric bypass. Unlike internal hernias, which tend to occur later in the clinical course and are associated with significant weight loss, Roux limb obstruction occurs earlier after gastric bypass and is not associated with significant weight loss. Interrupted closure of the mesocolic window might reduce the risk of Roux compression.     

Malabsorptive gastric bypass in patients with superobesity

Weight loss in superobese patients has been problematic after conventional gastric restrictive operations including conventional Roux-en-Y gastric bypass (RYGB). The goal of the present study was to compare weight loss in patients with superobesity (body mass index ≥50 kg/m²) using a distal RYGB (D-RY) in which the Roux-en-Y anastomosis was performed 75 cm proximal to the ileocecal junction (N = 47) vs. patients who had Roux limbs of 150 cm (N = 152) and 50 to 75 cm (N = 99). All operations incorporated the same gastric restrictive parameters. Minimum follow-up was 3 years and ranged to 16 years. Weight loss and reduction in body mass index were significantly greater after D-RY vs. both RYGB-150 cm and short RYGB and in RYGB-150 cm vs. short RYGB through 5 years. Mean percentage of excess weight loss peaked at 64% after DRY, at 61% after RYGB-150 cm, and at 56% after short RYGB. Weight loss maintenance through 5 years was correlated with Roux limb length with D-RY greater than RYGB-150 cm greater than short RYGB. More than 95% of obesity-related comorbid conditions improved or resolved with weight loss. There was no difference in the early postoperative morbidity rates: 9% after D-RY; 8% after RYGB-150 cm; and 2% after short RYGB with one death (0.3 %). All D-RY patients had at least one postoperative metabolic abnormality. Anemia was significantly more common after D-RY vs. the shorter RYGB with no difference in the incidence of metabolic sequelae between RYGB-150 cm and short RYGB. No operations were reversed or modified for nutritional complications. Two D-RY patients required total parenteral nutrition for protein malnutrition. These results show that Roux limb length is correlated with weight loss in superobese patients. However, the greater incidence of metabolic sequelae after D-RY vs. RYGB-150 cm calls into question its routine use in superobese patients undergoing bariatric surgery. We conclude that some degree of malabsorption should be incorporated into bariatric operations performed in superobese patients to achieve satisfactory long-term weight loss. Presented at the Forty-Second Annual Meeting of The Society for Surgery of the Alimentary Tract, Atlanta, Georgia, May 20–23, 2001.     

Long-long limb Roux-en-Y gastric bypass is more efficacious in treatment of type 2 diabetes and lipid disorders in super-obese patients.

BACKGROUND: Super-obese patients can achieve adequate weight loss with long limb Roux-en-Y gastric bypass (RYGB). These patients, however, might need longer intestinal limbs to control co-morbidities such as type 2 diabetes, lipid disorders, hypertension, sleep apnea, and gastroesophageal reflux disorder. METHODS: A total of 105 patients with a body mass index of > or =50 kg/m(2) were randomly divided into 2 similar groups regarding sex, age, and number of co-morbidities. All underwent laparoscopic Roux-en-Y gastric bypass. In group 1, the length of the biliary limb was 50 cm and the length of the Roux limb was 150 cm. In group 2, the length of the biliary limb was 100 cm and the length of the Roux limb was 250 cm. RESULTS: The follow-up for both group was 48 months. Diabetes was controlled in 58% of group 1 and in 93% of group 2 (P <0.05). Lipid disorders improved in 57% of group 1 and in 70% of group 2 (P <0.05). No statistical difference was found in the control or improvement of hypertension, sleep apnea, or gastroesophageal reflux disorder. The excess weight loss was faster in group 1 but was similar in both groups at 48 months (70% in group 1 and 74% in group 2), with no statistical difference. CONCLUSION: Patients with longer biliary and Roux limbs achieved greater type 2 diabetes control, greater lipid disorder improvement, and showed a trend toward faster excess weight loss.     

Small-Bowel Volvulus in Late Pregnancy Due to Internal Hernia After Laparoscopic Roux-en-Y Gastric Bypass

Internal hernias are a specific cause of acute abdominal pain and are a well-known complication after laparoscopic Roux-en-Y gastric bypass for morbid obesity. Although internal hernias are a rare cause of intestinal obstruction, they may evolve towards serious complications, such as extensive bowel ischemia and gangrene, with the need for bowel resection and sometimes for a challenging reconstruction of intestinal continuity. The antecolic position of the Roux limb is associated with a decrease in the incidence of small-bowel obstruction and internal hernias. The best prevention of the formation of these hernias is probably by closure of potential mesenteric defects at the initial operation with a non-absorbable running suture. We present a patient in late pregnancy with a small-bowel volvulus following laparoscopic Roux-en-Y gastric bypass for morbid obesity and discuss the available literature. For a favorable obstetric and neonatal outcome, it is crucial not to delay surgical exploration and an emergency operation usually is mandatory.     

Long-long limb Roux-en-Y gastric bypass is more efficacious in treatment of type 2 diabetes and lipid disorders in super-obese patients

BackgroundSuper-obese patients can achieve adequate weight loss with long limb Roux-en-Y gastric bypass (RYGB). These patients, however, might need longer intestinal limbs to control co-morbidities such as type 2 diabetes, lipid disorders, hypertension, sleep apnea, and gastroesophageal reflux disorder.MethodsA total of 105 patients with a body mass index of ≥50 kg/m² were randomly divided into 2 similar groups regarding sex, age, and number of co-morbidities. All underwent laparoscopic Roux-en-Y gastric bypass. In group 1, the length of the biliary limb was 50 cm and the length of the Roux limb was 150 cm. In group 2, the length of the biliary limb was 100 cm and the length of the Roux limb was 250 cm.ResultsThe follow-up for both group was 48 months. Diabetes was controlled in 58% of group 1 and in 93% of group 2 (P <0.05). Lipid disorders improved in 57% of group 1 and in 70% of group 2 (P <0.05). No statistical difference was found in the control or improvement of hypertension, sleep apnea, or gastroesophageal reflux disorder. The excess weight loss was faster in group 1 but was similar in both groups at 48 months (70% in group 1 and 74% in group 2), with no statistical difference.ConclusionPatients with longer biliary and Roux limbs achieved greater type 2 diabetes control, greater lipid disorder improvement, and showed a trend toward faster excess weight loss.     

Bipolar sealing increases mesenteric reach during bowel transection compared with stapled division: clinical evidence and laboratory support in a porcine model

BACKGROUND: The ideal technique for mesenteric division to create tension-free anastomoses has not been defined. For patients undergoing Roux-en-Y gastric bypass (RYGB), the mesenteric division technique was changed from stapler to bipolar sealing using LigaSure for cost reasons. This study aimed objectively to assess the impact of the mesenteric division method on mobilization length of the Roux limb in an animal model. Clinical complications related to Roux limb tension also were analyzed in the authors' population of RYGB patients. METHODS: Bowel and mesenteric divisions were performed in a porcine model. Four pigs received six to eight mesenteric divisions each. Steady force was applied for 1 min. The distances between the divided limbs of bowel were compared. To assess the clinical impact with RYGB patients, anastomotic complications were analyzed before and after incorporation of bipolar sealing in the authors' practice. RESULTS: In the porcine model, the length of mesenteric stretch averaged 93.7 mm with stapled division and 109 mm with bipolar sealing (p = 0.021). From a laparoscopic RYGB population, 160 patients with stapled division were included, all of whom were at least 1 year beyond their surgery. The study analyzed 792 patients with bipolar sealing for leak or bleeding and included 479 bipolar sealed patients more than 1 year beyond their surgery for analysis of their strictures. No difference in bleeding or leaks was found between these groups. The stricture rate was significantly different, with seven strictures after stapled division (4.37%) compared with one stricture after bipolar sealing (0.2%; p = 0.001). CONCLUSIONS: Bipolar sealing for mesenteric division is superior to stapling for optimization of enteric limb length at constant tension in a laboratory model. Clinical evidence supports this hypothesis with patients undergoing RYGB surgery by a decrease in the complications that can arise from Roux limb tension.     

American Society for Metabolic and Bariatric Surgery literature review on the effect of Roux-en-Y gastric bypass limb lengths on outcomes

This literature review is issued by the American Society for Metabolic and Bariatric Surgery regarding limb lengths in Roux-en-Y gastric bypass (RYGB) and their effect on metabolic and bariatric outcomes. Limbs in RYGB consist of the alimentary and biliopancreatic limbs and the common channel. Variation of limb lengths in primary RYGB and as a revisional option for weight recurrence after RYGB are described in this review.     

Laparoscopic conversion of failed gastric bypass to duodenal switch: technical considerations and preliminary outcomes

BACKGROUND: Weight loss failure after Roux-en-Y gastric bypass (RYGB) is a challenging problem facing bariatric surgeons today. Conversion from RYGB to biliopancreatic diversion with duodenal switch (BPD-DS) might provide the most durable weight loss of all revision procedures currently available. Revision to BPD-DS can be done laparoscopically in 1 or 2 stages and involves 4 anastomoses: gastrogastrostomy, duodenoileostomy, ileoileostomy, and jejunojejunostomy (to reconnect the old Roux limb). This study reports on our early outcomes after laparoscopic conversion from RYGB to BPD-DS. METHODS: The data from all patients undergoing conversion from failed RYGB to BPD-DS were retrospectively reviewed. The data analyzed included age, body mass index, excess weight loss, method of gastrogastrostomy, and morbidity/mortality. RESULTS: Twelve patients were identified for analysis. The mean age and body mass index before conversion was 41 years and 41 kg/m(2), respectively. Of these 12 patients, 4 (33%) had undergone revision surgery (lengthening of the Roux limb, resizing the gastric pouch, adjustable band on pouch, or distal gastric bypass) before conversion; 8 (66%) had obesity-related co-morbidities; 7 (58%) underwent conversion to BPD-DS in 1 stage. Most gastrogastrostomies were performed using the 25-mm circular stapler. No patient died and no leaks developed. One patient required laparotomy, and 4 developed stricture at the gastrogastrostomy. The patients lost a dramatic amount of weight after conversion to BPD-DS, with a mean body mass index and excess weight loss of 31 kg/m(2) and 63%, respectively, at 11 months postoperatively. All co-morbidities resolved completely with the weight loss. CONCLUSION: Our preliminary results indicate that laparoscopic conversion to BPD-DS from failed RYGB is highly effective with an acceptable morbidity. Using a linear stapler to construct the gastrogastrostomy might reduce the stricture rate.     

The role of total alimentary limb length in Roux-en-Y gastric bypass: a systematic review

BackgroundRoux-en-Y gastric bypass (RYGB) is an established surgical treatment for obesity. Variations in limb length during RYGB procedures have been investigated for optimizing weight loss while minimizing nutritional deficiencies. The role of the total alimentary limb length (TALL; Roux limb plus common channel [CC]), however, is poorly defined.ObjectiveCompare TALL in RYGB procedures for weight loss outcomes and malnutrition.SettingSystematic review.MethodsOvid Medline and PubMed databases were searched for entries between 1993 and 2020. Search terms included “gastric bypass” and “TALL.” Two independent reviewers screened the results.ResultsA total of 21 studies measured TALL in RYGB. Of these, 4 of 6 reported a relationship between TALL and weight loss. Additionally, 11 studies reported that when TALL was ≤400 cm and CC <200 cm, 3.4% to 63.6% of patients required limb lengthening for protein malnutrition.ConclusionsThe majority of studies on RYGB do not report TALL length. There is some evidence that weight loss is affected by shortening TALL, while a TALL ≤400 cm with CC<200 should be avoided due to severe protein malnutrition. More studies on the effect of TALL are needed.     

Short-term results of long biliopancreatic limb Roux-en-Y gastric bypass—is it superior?

ObjectivesTo compare the short-term safety and effectiveness of long biliopancreatic limb Roux-en-Y gastric bypass (RYGB) to that of regular RYGB.SettingAcademic hospital, United States.MethodsA retrospective chart review was performed on 89 consecutive patients who underwent RYGB between February 4, 2014 and March 12, 2015. Of these, 43 underwent long biliopancreatic limb RYGB (150 versus 60 cm, with 100-cm Roux limb).ResultsBaseline characteristics including sex, preoperative body mass index, and co-morbidities were similar between the long- and regular-limb RYGB patients. Long-limb patients were older than regular-limb patients. The median length of hospital stay was similar (2 d for both groups). In the long-limb RYGB group, the mean percentage of excess body mass index loss was 50.3%, 71.4%, 75.8%, and 80.5% at 6, 12, 24, and 36 months after the procedure, respectively. In the regular-limb RYGB group, the mean excess body mass index loss was 51.8%, 71.7%, 69.3%, and 68.5% during the same follow-up period. No significant difference in weight loss was observed between the 2 groups at any time point. Two patients in each group required 30-day readmission (4.7% and 4.3%). Two patients in each group required 30-day reoperation. One death occurred in the regular limb group due to a cerebrovascular accident after discharge.ConclusionsShort-term results show that long biliopancreatic limb RYGB was not associated with a more significant weight loss after RYGB. The 2 procedures were similar in 30-day complications.     

Errant and unrecognized antiperistaltic Roux limb construction during Roux-en-Y gastric bypass for clinically significant obesity

BACKGROUND: Proper isoperistaltic orientation of the Roux limb is important. We report on 5 patients with errant anatomic construction of the Roux limb during Roux-en-Y gastric bypass for clinically significant obesity. METHODS: We performed a retrospective review of the medical records of these 5 patients. Of the 5 patients, 3 had undergone open and 2 laparoscopic Roux-en-Y gastric bypass. RESULTS: These 5 patients developed persistent and predominantly bilious vomiting in the immediate postoperative period, with subsequent protein-calorie malnutrition. At least 18 operations were undertaken in these 5 patients at different times to correct the abnormally dilated Roux limb to no avail. The diagnosis of an antiperistaltic anatomy was unsuspected, and these operations failed to address the errant anatomy of the Roux limb or resolve the symptoms. Definitive treatment involved repositioning of the Roux limb in an isoperistaltic direction, which resulted in immediate resolution of the symptoms and reversal of the protein-calorie malnutrition. CONCLUSION: Antiperistaltic Roux anatomy is deleterious, and repositioning of the Roux limb in an isoperistaltic direction will resolve the symptoms and associated protein-calorie malnutrition.     

Laparoscopic and thoracoscopic Ivor Lewis esophagectomy after Roux-en-Y gastric bypass

Roux-en-Y gastric bypass is a commonly performed procedure for the treatment of morbid obesity. Esophagectomy in patients with a history of Roux-en-Y gastric bypass presents a difficult technical challenge for the surgeon. In this report we describe a technique of minimally invasive Ivor Lewis esophagogastrectomy in a patient who had had an open Roux-en-Y gastric bypass. Minimally invasive esophagectomy was performed with resection of the Roux limb using the gastric remnant as the conduit for gastrointestinal reconstruction.     

Gastric Bypass Surgery in Rats Produces Weight Loss Modeling after Human Gastric Bypass

Background  The study of the mechanisms of weight loss after bariatric surgery requires an animal model that mimics the human procedure and subsequent weight loss. A rat model eliminates the cognitive efforts associated with human weight loss and gain. Methods  A technique for gastric bypass (Roux-en-Y gastric bypass [RYGB]) was developed in Sprague–Dawley rats. A 1- to 2-cc pouch is created from the uppermost stomach using a linear stapler. A 10-cm biliopancreatic limb and 15-cm Roux limb are anastomosed side to side with running nonabsorbable suture. The gastrojejunostomy is created with a single layer of running nonabsorbable suture. Four rats underwent RYGB. Weight loss was compared to four sham rats that had a midline incision and left 60 min with an open abdomen before closure. Results  RYGB rats lost an average of 16.5% body weight (BW) at 1 week, 22% BW at 2 weeks, 20% BW at 3 weeks, and 11% BW at 4 weeks. The RYGB rat’s weight was basically level after 4 weeks. The shams lost an average of 4% BW at 1 week, 1% BW at 2 weeks, and 0% BW at 3 weeks and gained an average of 2% at weeks. Subjectively, the RYGB rats were less interested in chow and frequently had chow left in their cage. Conclusion  A Sprague–Dawley rat model for gastric bypass has been developed and yields approximately 11% BW loss. This will allow investigators to objectively view factors associated with weight loss without the confounding cognitive factors in humans. Presented at the 24th Annual Meeting of the American Society for Bariatric Surgery; June 16, 2007; San Diego, CA.     

Internal hernias in pregnant females with Roux-en-Y gastric bypass: a systematic review

Improved fertility following a Roux-en-Y gastric bypass (RYGB) can lead to pregnancy and increase the risk of internal herniation. A developing fetus and symptoms of pregnancy can mask the diagnosis and delay intervention, leading to deleterious maternal and fetal consequences. The aim of this systematic review is to summarize the literature regarding internal hernias during pregnancy, their management, and patient outcomes. A comprehensive literature search was undertaken on PubMed and Google Scholar to identify cases of internal hernias presenting during pregnancy after RYGB. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used for eligibility and inclusion of articles. Twenty-seven articles, with a total of 59 patients, regarding internal herniation during pregnancy after RYGB were identified. Epigastric pain and nausea and vomiting was the most common presentation. Regardless of orientation of the Roux limb and despite previous closure of mesenteric defects, internal herniation can still occur. A triad of epigastric pain, pregnancy, and a history of RYGB should be a red flag for clinicians to consider internal hernias as a top differential diagnosis. Prompt bariatric consultation and rapid intervention will improve maternal and fetal outcomes.     

Five-year outcome with gastric bypass: Roux limb length makes a difference

BackgroundSurgical reports have indicated that longer Roux limbs (150 cm) have greater or no effect on long-term weight loss in super-obese patients (body mass index [BMI] ≥50 kg/m²) and little effect in less obese patients.MethodsThe weight loss outcomes through 5 years were compared in 3 sequential groups of patients, who underwent gastric bypass by 1 surgeon, and in whom the Roux limb lengths were different. Comparisons were made between 2 cohorts: those with a BMI of <50 (morbid obesity [MO]) and those with a BMI ≥50 kg/m² (super obesity [SO]). Three groups of patients stratified by Roux limb lengths were compared: group 1, 41–61-cm Roux limb; group 2, 130–160-cm Roux limb; and group 3, 115–250-cm Roux limb (one third of small bowel). All comparisons were made using 2-way analysis of variance, and the interaction terms were not significant.ResultsA comparable number of patients were in each group, and the average preoperative weights were similar; however, more than twice as many patients in groups 2 and 3 were SO than MO. The BMI loss and weight loss were similar in each group. The greater BMI cohort (SO) lost more weight than did the MO cohort (P <.001). The BMI change and weight change in the shorter Roux limb group were less than those in groups 2 or 3 (longer Roux limbs; P <.01–.05). This difference was established with the BMI by 18 months. The BMI change and weight loss were not different between groups 2 and 3, presumably because their mean Roux limb lengths were not different. A limited amount of weight gain or recidivism occurred in patients with 5 years of follow-up, and it was not different among the 3 groups.ConclusionThe results of this study have shown that longer Roux limbs improve weight loss outcomes both early and late in SO patients but not in MO patients. Clinically used long lengths of Roux limbs are close enough to one third of the total small bowel length such that the weight outcomes were not different, and total length should not need to be measured operatively. The eventual changes attributed to recidivism were not affected by the Roux limb length.     

Hepaticojejunostomy for the management of sump syndrome arising from choledochoduodenostomy in a patient who underwent bariatric Roux-en-Y gastric bypass: A case report

IntroductionRapid weight loss following bariatric surgery is associated with high incidence of gallstones and complications that may need bilioenteric diversion. This presents a specific challenge in the management of this group of patients.Case presentationA 37 years old female underwent a Roux-en-Y gastric bypass (RYGB) in 2008 for morbid obesity. In 2009 she presented with obstructive jaundice and was diagnosed with choledocholithiasis successfully managed by open cholecystectomy and choledochoduodenostomy. In the following years, she developed recurrent attacks of fever, chills, jaundice, and right upper quadrant pain and her weight loss was not satisfactory. Imaging of the liver showed multiple cholangitic abscesses. Reflux at the choledochoduodenostomy site was suggestive of sump syndrome as a cause of her recurrent cholangitis and a definitive surgical treatment was indicated. Intraoperative findings confirmed sump at the choledochoduodenostomy site and also revealed the presence of a large superficial accessory duct arising from segment four of the liver with separate drainage into the duodenum distal to the choledochoduodenostomy site. A formal hepaticojejunostomy was done after ductoplasty. The Roux limb was created by transecting the jejunum 40 cm distal to the foot anastomosis of the RYGB. The gastric limb was lengthened as part of this procedure which afforded the patient the additional benefit of weight loss.ConclusionCholedochoduodenostomy should be avoided in patients with RYGB due to the risk of sump syndrome which requires conversion to a formal hepaticojejunostomy.     

Internal Hernia with Roux Loop Obstruction during Pregnancy after Gastric Bypass Surgery

We report the rare case of a pregnant woman who had undergone Roux-en-Y gastric bypass 8 months previously, and now presented with subacute small bowel obstruction secondary to internal herniation of some of the proximal Roux limb into the lesser sac through the transverse mesocolon rent, which was widely spread apart. At laparoscopy, the hernia contents were reduced and the defect was repaired. The patient made a good recovery. Because of the changes associated with pregnancy, gastric bypass patients may be at an increased risk of internal herniation. It is particularly important not to delay surgical exploration, even in the absence of a positive finding on imaging, because delay may lead to potentially devastating bowel strangulation and sepsis culminating in loss of fetus and mother.     

The Importance of the Length of the Limbs for Gastric Bypass Patients—An Evidence-based Review

The ideal length of the gastric bypass limbs is debated. Recent evidence suggests that standard limb lengths used today have a limited impact on patient weight loss. Our objective was to appraise critically the available evidence on the influence of the length of gastric bypass limbs on weight loss outcomes. We systematically reviewed MEDLINE, the Cochrane database of evidence-based reviews, and the Database of Abstracts of Reviews of Effects for articles reporting the effect of gastric bypass length on outcomes published between 1987 and 2009. Four randomized controlled trials and several retrospective studies were identified and reviewed. Longer Roux limb lengths (at least 150 cm) were associated with a very modest weight loss advantage in the short term in superobese patients. No significant impact of alimentary limb length on weight loss for patients with body mass index (BMI) <50 was seen. When the length of the common channel approaches 100 cm, a significant impact on weight loss is observed. The currently available literature supports the notion that a longer Roux limb (at least 150 cm) may be associated with a very modest weight loss advantage in the short term in superobese patients but has no significant impact on patients with BMI ≤50. To achieve weight loss benefit due to malabsorption, bariatric surgeons should focus on the length of the common channel rather than the alimentary or biliopancreatic limbs when constructing a gastric bypass especially in the superobese population where failure rates after conventional gastric bypass are higher.