The Banded Gastric Bypass

(For the treatment of Morbid Obesity)


The banded gastric bypass (BGBP) operation is a gastric bypass procedure, in which a Ring or Band is placed around the pouch to provide a fixed outlet from the gastric bypass pouch.

The banded gastric bypass operation requires the creation of a gastric pouch 5-7 cm long 20-30cc in size by vertically transecting the stomach just distal to the gastro-esophageal junction. A gastro-jejunostomy anastomosis ~2cm in width is formed to provide gastro intestinal continuity. A ring is placed around the gastric pouch approximately 2 cm above the gastro-enterostomy site to provide a stabilized outlet.

Surgical Treatment of Obesity

The obesity epidemic continues to persist despite global educational efforts and treatment with diet, exercise, and pharmaceuticals. Morbid obesity is closely associated with co-morbid conditions experienced in different facets of life. Medical conditions associated with morbid obesity include diabetes, sleep apnea, hypertension, arthritis, GERD and pseudotumor cerebri. In addition to the aforementioned co-morbidities, there are a host of other negative collateral effects such as social degradation, physical limitations, detrimental economic implications (most often due to limited employment opportunities, higher cost of living, higher cost of medical care), and psychological ramifications (e.g. low self-esteem and depression) ramifications that aggregate in the form of a. overall diminished quality of life for morbidly obese individuals. To date, metabolic/bariatric surgery remains the most effective intervention for morbid obesity with documented greater than 50% excess weight loss (EWL) maintained beyond 10 years.

Evolution of the Banded Gastric Bypass Procedure.

In 1967, the primary gastric bypass with a loop gastro-jejunostomy was introduced by Mason and Ito (Fig.1a) to treat morbid obesity based on the observation that patients who had subtotal gastrectomy for ulcer disease, which leaves a small gastric pouch, lost weight and maintained their weight loss in the long term [1]. In light of this discovery, the ulcer operation was modified to a gastric bypass operation for weight loss. The gastric bypass operation was further modified to a Roux-en-Y Gastric bypass, (RYGBP) (Fig.1b), with a pouch 20- 30 cc in size and a 1-2 cm diameter pouch outlet as it became apparent the pouch and outlet size was important to maximize weight loss [2]. This modified gastric bypass became the standard for Bariatric operation, and it is widely used today.

The RYGBP effectiveness, at that time, was perceived to be due to the small size of the pouch. This perception and the morbidity and mortality rates at that time from the gastric bypass operation prompted Mason to introduce a simpler and safer gastroplasty operation, the horizontal gastroplasty (Fig.1c), with a small pouch and a 1-2cm stoma and without bypassing any part of the gastro-intestinal tract. The initial weight loss with this operation was comparable to that of the RYGBP; however, with follow-up beyond one year, there was a high failure rate with partial or complete weight regain in some cases. The failure of the horizontal gastroplasty was determined to be attributable to the dilation of the pouch outlet. In 1980, Mason modified the gastroplasty operation to a vertical banded gastroplasty (VBG) (Fig.1d) with a surgeon-fashioned band placed around the pouch to stabilize the outlet [3]. This prevented pouch and stoma dilation and greatly enhanced the weight loss and weight loss maintenance after the VBG operation. In 1991, the NIH endorsed the RYGBP and the VBG as operations that provided viable long-term treatment of obesity [4].


Fig 1. (a) gastric bypass with loop; (b) RYGBP; (c) horizontal gastroplasty; (d) VGB

Beyond four years of the modified Roux-en-Y gastric bypass operation, surgeons started observing weight regain and failure of the gastric bypass in a subset of patient. This failure was determined to be mainly due to pouch and outlet dilation of the gastric bypass operation. In 1984, based on the observation of banding the pouch outlet in the VBG, Linner started placing a band around the gastro-jejunal anastomosis to stabilize the pouch outlet (Fig.2a) [5]. However, placement of a band at the anastomotic site resulted in a high rate of migration. Therefore, in 1986, Fobi modified the method of banding the gastric bypass by placing the band around the gastric pouch at least 2cm proximal to the anastomosis (Fig. 2b). This procedure is referred to as the banded gastric bypass (BGBP) [6]. Fobi reported better weight loss, weight loss maintenance and a 2% rate of band migration with the BGBP, which has been corroborated by multiple reports of long-term clinical investigations [7-12].


Fig 2. (a) Gastric bypass with band at the anastomosis; (b) BGBP

Weight Loss Mechanisms of the Gastric Bypass

The Banded Gastric Bypass (GBP) has proved to be the most consistently successful treatment for obesity for the greatest number of patients. The mechanisms of action operating in the banded gastric bypass include:

  • Neural Stimulation of gastro-esophageal (GE) junction (Full Sense) – When patients fill the pouch with food to the point that the proximal GE junction stretches and the nerves are stimulated, they will feel a sense of fullness;
  • Restriction – The small size of surgically created pouch and pouch outlet restricts the amount of food a patient can ingest before distending the GE junction. The stabilized outlet slows the transit of food out of the pouch, thus prolonging the feeling of satiation;
  • Malabsorption – Selective mal absorption results from the bypassing of the gastro-duodenal axis. The delayed mixture of the food with the pancreatic enzymes and bile acids, due to bypassing the gastro-duodenal axis, results in decreased digestion and selective mal absorption of fats;
  • Ghrelin Effect – The Ghrelin hormone is produced in the stomach and stimulates hunger in the brain. Bypassing the stomach results in decreased secretion of Ghrelin hormone resulting in anorexia with diminished desire to take in calories;
  • Neurotensisn (Dumping Syndrome) – Direct transit of food from the pouch into the small bowel results in mild dumping, thus decreasing the patient’s desire for intake of calorically dense foods;
  • Enterokinin Effect – Secretion of incretins, GLP-1, GIP and PYY, from the foregut and hindgut alters taste and desired food intake, resulting in decreased caloric intake;
  • Gut Micro Biota – Change in the bacterial flora of the gastro-intestinal tract after the banded gastric bypass alters taste and the desire for food, resulting in decreased caloric intake; and
  • Patient Compliance – Patients must be motivated and willing to adjust their dietary habits, must keep in contact with their physician, and must follow physician recommendations [12-14].

The surgically created pouch and pouch outlet size are important to the effectiveness of the restriction and full sense mechanisms of the banded gastric bypass procedure If the restrictive mechanism is not moderately maintained, a subset of patients will experience complications associated with pouch outlet dilation, including inadequate weight loss, weight regain, return of their co-morbid conditions, other complications [6, 15-16] and very frequently revisional surgeries with the associated consequences.

Why does the Gastric Bypass Fail?

Pouch outlet dilation is a part of the gastric anatomy’s natural history after the gastric bypass procedure [16-18]. However, pouch outlet dilation, at the gastro-jejunal anastomosis to a diameter beyond 2 – 3 cm may defeat the restriction mechanism, since ingested food will pass freely through the pouch and pouch outlet, directly into the bowel [6, 16]. Pouch outlet dilation result in a loss of the restrictive mechanism of the gastric bypass procedure and results in the formation of a gastric food reservoir that is comprised of the surgically created pouch, pouch outlet, and proximal small bowel [6, 15, 19]. This dilation allows patients to ingest more food before achieving the full sense [17, 20]. Loss of restriction at the pouch outlet is a significant anatomic factor leading to adverse weight loss outcomes after the gastric bypass procedure [16, 21-23]. Other factors that can cause dilation include patient eating patterns and associated variations in caloric intake – patient compliance [16]. A subset of gastric bypass patients (up to 40%) will fail to achieve successful weight loss outcomes due to pouch outlet dilation, and will experience associated complications including:

  • Inadequate weight loss – A dilated pouch outlet allows patients to increase their food intake. As a result, a subset of patients will fail to achieve > 50 percent excess weight loss (%EWL). Inadequate weight loss may result in decreased resolution of co-morbid conditions (diabetes, high blood pressure, sleep apnea, and GERD) and may require reoperation.
  • Weight regains – A dilated pouch outlet allows patients to increase their food intake. As a result, a subset of patients may achieve successful weight loss (> 50 %EWL) but will subsequently regain a significant amount of the weight lost. Weight regain may result in the recurrence of co-morbid conditions and may require surgical revision.
  • Increased incidence of severe Dumping Syndrome – A dilated pouch outlet allows ingested food to rapidly pass through the pouch and enter the bowel largely undigested, causing sweatiness, shakiness and sometimes nausea, vomiting and diarrhoea.
  • Increased incidence of Reactive Hypoglycaemia – A dilated pouch outlet allows ingested food to rapidly pass through the pouch and enter the bowel largely undigested, resulting in a severe form of dumping syndrome causing hunger, weakness, low blood sugar, lightheadedness and syncope.
  • Increased incidence of GERD – A dilated pouch and pouch outlet allows the ingestion of large amounts of food, resulting in some food reverting back into the esophagus as the bowel contracts.
  • Medical or surgical treatment of the above complications – A dilated pouch outlet that results in any of the above complications requires medical or surgical treatment, and subjects patients to the higher rate of complications associated with post-operative surgical treatment.

Addressing Procedural Failure Due to Pouch Outlet Dilation

Several methods have been employed to address the dilation of the pouch and outlet in failed gastric bypass procedures, including: (1) surgical revision to reduce pouch and pouch outlet size; (2) endoscopic revision of pouch outlet size; (3) revisional gastric banding using adjustable and non-adjustable gastric bands; and (4) the placement of a band around the pouch during the primary gastric bypass operation to create a stabilized pouch outlet using surgeon-fashioned devices, adjustable gastric bands used off-label, or the devices now available specifically to band the pouch in the gastric bypass procedure.

Surgical revision involves resection of the pouch and the creation of a new smaller pouch outlet to recreate the restriction once provided by the gastric bypass [24].

Endoscopic revision involves a variety of methods including Sclerotherapy (injection of a sclerosant in perianastomotic tissue), Suturing Systems (placing sutures at the dilated gastrojejunostomy to reduce its size, e.g. Bard EndoCinch Suturing System, OverSticth Endoscopic Suturing System), and Plication (though generally limited to resizing the pouch and not the pouch outlet, e.g. StomaphyX, and the ROSE – restorative obesity surgery endoscopic, procedure) [25].

Banding the gastric bypass as a revisional operation involves the placement of a band, usually an adjustable gastric band around an already dilated gastric pouch to recreate the restriction once provided by now dilated pouch outlet, in order to control food intake [26-27]. In the US, surgeons use approved adjustable gastric bands used off-label (e.g. Lap-Band or Realize Band) to halt additional weight regain or reinitiate weight loss. Many international surgeons now use prefabricated non-adjustable bands to band the dilated pouch to provide the stabilized pouch outlet.

Surgical revision, endoscopic revision and revisional placement of a band, non-adjustable or adjustable, are reactive means to address pouch outlet dilation after patients have already significantly experienced the complications associated with pouch outlet dilation [28]. Whereas, placing a band around the pouch during the primary gastric bypass operation is a proactive method to address pouch outlet dilation and its negative externalities.

The Banded Gastric Bypass Procedure

Placing a band around the surgically created pouch during the primary gastric bypass procedure to provide a stabilized restrictive pouch outlet is a proactive means of addressing pouch outlet dilation. A gastric bypass with a band around the pouch is referred to as the banded gastric bypass procedure. Surgeons have used various unregulated surgeon-fashioned devices and off-label devices to band the primary gastric bypass, including silicone tubing bands, polypropylene bands, Marlex or Gore-Tex mesh bands, fascia bands and bands approved for the adjustable gastric banding procedure [29-30]. There are now banding device designed and manufactured specifically to replace the bands currently used during BGBP operations, like the GaBP RingTM device, to provide a stabilized pouch outlet, and to help standardize the process of band placement in the BGBP procedure.

In the BGBP procedure, the band is loose around the pouch at implantation and does not affect the function of the gastric bypass anatomy immediately after operation. However, once the pouch dilates to a certain point, the device provides a new outlet proximal to the gastro-jejunostomy to slow the rate of food passage, and thus maintain the restrictive and full sense mechanisms of the gastric bypass procedure [20]. Despite any dilation proximally or distally to the band, as long as the band is in place, it will provide a stabilized pouch outlet to restrict the passage of food to the area distal to the device. Therefore, patients must only fill the area proximal to the device to distend the GE junction and reach satiety, and the effect of any distal dilation is non-consequential to the amount of food intake [8, 30-31].

An animated depiction of the expected change in the size of the gastric food reservoir over time with and without a band is provided in Figure 3.


Fig 3. Animated change in size of food reservoir, with and without a Band in place.

A radiographic illustrating of the change in the size of the gastric reservoir after 12 months based on radiological contrast swallow after a gastric bypass and a banded gastric bypass is shown in Figures 4 & 5.


Fig 4. Non-Banded gastric bypass with a dilated pouch, outlet and proximal jejunum


Fig 5. Banded gastric bypass with the Band site functioning as the stabilized gastric outlet

The BGBP procedure for weight loss is a well-documented operative procedure and is an accepted standard of care practice in bariatric surgery. The mechanism and benefits of the BGBP are well documented in bariatric surgery textbooks, published clinical investigations, prospective comparative studies, systematic reviews and a systemic review and meta-analysis in reputable surgical journals [31-34]. The banded gastric bypass provides more weight loss for more patients that are maintained for a longer period of time than other gastric bypass operations.