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Roux-en-Y Gastric Bypass

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Through out the 60-year history of bariatric surgery, many operative procedures have been developed, adopted, popularized, and ultimately abandoned due to poor long term results or unacceptable complications. However, the gastric bypass procedure has shown itself to be durable, effective and safe. Many believe that it remains the “Gold Standard” bariatric procedure by which all others must be compared.

Mason and Ito first developed the gastric bypass procedure in the mid 1960’s from their observation that patients lost weight after partial gastrectomy for ulcer disease. (1) The initial procedure was based on the Billroth II gastrectomy that was commonly performed for many decades to treat peptic ulcer disease and gastric cancer. Mason’s original gastric bypass procedure involved the horizontal transection of the proximal stomach to create a small gastric segment (referred to as a pouch) and then anastomosing a loop of jejunumto the greater curvature side of the pouch.

Roux-En-Y gastric bypass, obesity

Although effective for weight loss, the original horizontal loop gastric bypass was a challenging procedure to perform and had a significant major complication rate. Additionally, although the procedure was effective for achieving significant weight loss, there was a high rate of pouch dilatation and weight regain. Over the ensuing years, surgeons modified the procedure to decrease the rate of serious complications and reduce the likelihood of pouch dilatation and weight regain. Significant advances in technique included the use of vertical stapling instead of horizontal and the construction of a lesser curvature based pouch which is more resistant to dilatation. Additionally, the conversion from open surgery to laparoscopic reduced complications and made the procedure acceptable to many patients. To reduce bile reflux, most surgeons adopted a roux anastomosis (roux-en-Y gastric bypass) rather than an intestinal loop (although some surgeons continue to prefer the loop construction {One Anostomosis Gastric Bypass}).

Currently, there are numerous variations in the construction of the gastric bypass. Pouch size and limb length varies. Limb orientation (retrocolic, retrogastric, antecolic, antegastric) also varies. The gastrojejunal anastomosis can be created with a linear stapler, circular stapler, or hand sewn. The pouch and anastomosis may or may not be banded. However, despite all of the variation, all gastric bypass procedures are basically similar in that they all have a small gastric pouch that drains into the small bowel so that the nutrient stream is diverted away from the gastric fundus and antrum, the duodenum and proximal jejunum.

There is currently a wealth of published literature describing the performance of the gastric bypass. 75-85% of patients will maintain an average of 50% excess weight loss long term (2). Weight loss after one year is generally reported to be 65-75% of excess. A considerable number of obesity-related disorders such as type 2 diabetes mellitus, hypertension, obstructed sleep apnea, polycystic ovarian syndrome, gastroesophageal reflux, etc, will improve or resolve altogether after successful surgery (3). Recently, several prospective, randomized trials comparing gastric bypass surgery to sleeve gastrectomy surgery or medical therapy reported the gastric bypass to be superior to both for weight loss and the improvement in diabetes and other metabolic disorders (4,5).

The laparoscopic gastric bypass as performed today, has become a much safer and efficacious procedure than its ancestors. Thirty-day mortality is reported to be less than 0.2% (6). Leaks occur in 1-2%, hemorrhage in 2-5%, thromboembolism <1% most other complications occur in just a few percent of patients (7). It remains the gold standard procedure by which all others should be compared.


  • Mason E, Ito C. Gastric bypass in obesity. SurgClin North Am 1967;47:1345-51.
  • Pories WJ, Swanson MS, MacDonald KG, et al. Who would have thought it? An operation proves to be the most effective therapy for adult-onset diabetes mellitus. Ann Surg 1995;222:339-352.
  • Schauer PR, Ikramuddin S, Gourash W, Ramanathan R, Luketich J. Outcomes after laparoscopic Roux-en-Y gastric bypass for morbid obesity. Annals of surgery. 2000;232:515-29.
  • Ikramuddin S, Korner J, Lee WJ, et al. Roux-en-Y Gastric Bypass vs intensive medical management for the control of type 2 diabetes, hypertension, and hyperlipidemia. The Diabetes Surgery Study randomized clinical trial. JAMA 2013;309:2240-9.
  • Schauer PR, Kashyap SR, Wolski K, etal. Bariatric surgery versus intensive medicaltherapy in obese patients with diabetes.N Engl J Med 2012;366:1567-76.
  • Longitudinal Assessment of Bariatric Surgery (LABS) Consortium, et al. N Engl J Med. Perioperative safety in the longitudinal assessment of bariatric surgery. 2009 Jul 30;361:445-54.
  • Shikora SA, Kim JJ, Tarnoff ME, et al. Laparoscopic Roux-en-Y gastric bypass: results and learning curve of a high-volume academic program. Arch Surg. 2005;140:362-7.