Mini Gastric Bypass

Gastric Bypass Surgery

Gastric bypass surgery refers to a surgical procedure in which the stomach is divided into a small upper pouch and a much larger lower “remnant” pouch and then the small intestine is rearranged to connect to both. Surgeons have developed several different ways to reconnect the intestine, thus leading to several different gastric bypass (GBP) procedures. Any GBP leads to a marked reduction in the functional volume of the stomach, accompanied by an altered physiological and physical response to food.

The operation is prescribed to treat morbid obesity (defined as a body mass index greater than 40), type 2 diabetes, hypertension, sleep apnea, and other comorbid conditions. Bariatric surgery is the term encompassing all of the surgical treatments for morbid obesity, not just gastric bypasses, which make up only one class of such operations. The resulting weight loss, typically dramatic, markedly reduces comorbidities. The long-term mortality rate of gastric bypass patients has been shown to be reduced by up to 40%. As with all surgery, complications may occur. A study from 2005 to 2006 revealed that 15% of patient’s experience complications as a result of gastric bypass, and 0.5% of patients died within six months of surgery due to complications.

Since 1991, major developments in the field of bariatric surgery, particularly laparoscopy, have outdated some of the conclusions of the NIH panel. In 2004 the American Society for Bariatric Surgery (ASBS) sponsored a consensus conference which updated the evidence and the conclusions of the NIH panel. This conference, composed of physicians and scientists of both surgical and non-surgical disciplines, reached several conclusions, including:

  • bariatric surgery is the most effective treatment for morbid obesity
  • gastric bypass is one of four types of operations for morbid obesity
  • laparoscopic surgery is equally effective and as safe as open surgery
  • patients should undergo comprehensive preoperative evaluation and have multi-disciplinary support for optimum outcome.

Surgical Techniques

The Roux-en-Y laparoscopic gastric bypass, first performed in 1993, is regarded as one of the most difficult procedures to perform by limited access techniques, but use of this method has greatly popularized the operation due to associated benefits such as a shortened hospital stay, reduced discomfort, shorter recovery time, less scarring, and minimal risk of incisional hernia.

The gastric bypass procedure consists of:

Creation of a small, (15–30 mL/1–2 tbsp) thumb-sized pouch from the upper stomach, accompanied by bypass of the remaining stomach (about 400 mL and variable). This restricts the volume of food which can be eaten. The stomach may simply be partitioned (like a wall between two rooms in a house or two office cubicles next to each other with a partition wall in between them – and typically by the use of surgical staples), or it may be totally divided into two separate/separated parts (also with staples). Total division (separate/separated parts) is usually advocated to reduce the possibility that the two parts of the stomach will heal back together (“fistulize”) and negate the operation.

Re-construction of the GI tract to enable drainage of both segments of the stomach. The particular technique used for this reconstruction produces several variants of the operation, differing in the lengths of small intestine used, the degree to which food absorption is affected, and the likelihood of adverse nutritional effects. Usually, a segment of the small bowel (called the alimentary limb) is brought up to the proximal remains of the stomach.

Variations Gastric Bypass Surgery

Gastric bypass, Roux en-Y (RYGB, proximal)

This variant is the most commonly employed gastric bypass technique, and is by far the most commonly performed bariatric procedure in the United States. The small intestine is divided approximately 45 cm (18 in) below the lower stomach outlet and is re-arranged into a Y-configuration, enabling outflow of food from the small upper stomach pouch via a “Roux limb”. In the proximal version, the Y-intersection is formed near the upper (proximal) end of the small intestine. The Roux limb is constructed using 80–150 cm (31–59 in) of the small intestine, preserving the rest (and the majority) of it from absorbing nutrients. The patient will experience very rapid onset of the stomach feeling full, followed by a growing satiety (or “indifference” to food) shortly after the start of a meal.

Gastric bypass, Roux en-Y (RYGB, distal

The small intestine is normally 6–10 m (20–33 ft) in length. As the Y-connection is moved further down the gastrointestinal tract, the amount available to fully absorb nutrients is progressively reduced, traded for greater effectiveness of the operation. The Y-connection is formed much closer to the lower (distal) end of the small intestine, usually 100–150 cm (39–59 in) from the lower end, causing reduced absorption (malabsorption) of food: primarily of fats and starches, but also of various minerals and the fat-soluble vitamins. The unabsorbed fats and starches pass into the large intestine, where bacterial actions may act on them to produce irritants and malodorous gases. These larger effects on nutrition are traded for a relatively modest increase in total weight loss.

“Mini-gastric bypass” (MGB)

The mini gastric bypass procedure was first developed by Robert Rutledge from the US in 1997, as a modification of the standard Billroth II procedure. A mini gastric bypass creates a long narrow tube of the stomach along its right border (the lesser curvature). A loop of the small gut is brought up and hooked to this tube at about 180 cm from the start of the intestine

Numerous studies show that the loop reconstruction (Billroth II gastrojejunostomy) works more safely when placed low on the stomach, but can be a disaster when placed adjacent to the esophagus. Today thousands of “loops” are used for surgical procedures to treat gastric problems such as ulcers, stomach cancer, and injury to the stomach. The mini gastric bypass uses the low set loop reconstruction and thus has rare chances of bile reflux.

The MGB has been suggested as an alternative to the Roux en-Y procedure due to the simplicity of its construction, and is becoming more and more popular because of low risk of complications and good sustained weight loss. It has been estimated that 15.4% of weight loss surgery in Asia is now performed via the MGB technique.

Endoscopic duodenal-jejunal bypass

This technique has been clinically researched since the mid-2000s. It involves the implantation of a duodenal-jejunal bypass liner between the beginning of the duodenum (first portion of the small intestine from the stomach) and the mid-jejunum (the secondary stage of the small intestine). This prevents the partially digested food from entering the first and initial part of the secondary stage of the small intestine, mimicking the effects of the biliopancreatic portion of Roux en-Y gastric bypass (RYGB) surgery. Despite a handful of serious adverse events such as gastrointestinal bleeding, abdominal pain, and device migration — all resolved with device removal — initial clinical trials have produced promising results in the treatment’s ability to improve weight loss and glucose.

Results and health benefits of gastric bypass surgery

  • Weight loss of 65–80% of excess body weight is typical of most large series of gastric bypass operations reported. The medically more significant effects include a dramatic reduction in comorbid conditions:
  • Hyperlipidemia is corrected in over 70% of patients.
  • Essential hypertension is relieved in over 70% of patients, and medication requirements are usually reduced in the remainder.
  • Obstructive sleep apnea improves markedly with weight loss and bariatric surgery may be curative for sleep apnea. Snoring also reduces in most patients.
  • Type 2 diabetes is reversed in up to 90% of patients usually leading to a normal blood-sugar level without medication, sometimes within days of surgery. Furthermore, Type 2 diabetes is prevented by more than 30-fold in patients with pre-diabetes. All these findings were first reported by Walter Pories and Jose F. Caro.
  • Gastroesophageal reflux disease is relieved in almost all patients.
  • Venous thromboembolic disease signs such as leg swelling are typically alleviated.
  • Lower-back pain and joint pain are typically relieved or improved in nearly all patients.

A study in a large prospective study of 2010 obese patients showed an 29% reduction in mortality up to 15 years following surgery (hazard ratio 0.71 when adjusted for sex, age, and risk factors), compared to a non-surgically treated group of 2037 patients.

Concurrently, most patients are able to enjoy greater participation in family and social activities.

mini gastric sleeve

mini gastric sleeve