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What is Malabsorptive Bariatric Surgery?

Malabsorptive bariatric surgery is a type of weight-loss surgery (bariatric surgery) employed to treat a medical condition called extreme or morbid obesity. The surgery restricts the quantity of nutrients the body can absorb by bypassing a section of the small intestine.

The only strict malabsorptive bariatric surgery is:

  • Biliopancreatic diversion

The two combination malabsorptive and restrictive bariatric surgeries are:

  • Roux-en-Y Gastric Bypass Surgery
  • Duodenal Switch urgery

Biliopancreatic Diversion (BPD): This is purely a malabsorptive bariatric surgery and is more complicated than gastric bypass surgery. It is a less common procedure and is usually reserved for patients who are severely obese. The procedure involves removal of a part of the stomach to restrict how much food the stomach can hold, along with diverting the gastrointestinal tract beyond some of the small intestine so fewer calories are absorbed. It is referred to as a malabsorptive procedure because the digested food from the stomach bypasses the first two segments of the small intestine, the duodenum, and the jejunum, significantly decreasing absorption of nutrients, which helps with weight loss.

Gastric Bypass Surgery: This is also known as Roux-en-Y gastric bypass surgery and is the most common bariatric surgery. The surgery involves a combination of restrictive (limits food intake) and malabsorptive (limits food absorption) techniques to achieve a successful outcome. Staples are used to create a smaller stomach to limit the amount of food intake, and a large portion of the small intestine is bypassed to limit the nutrients and calories absorbed. All gastric bypass surgeries are malabsorptive in nature. Some are a combination of both restriction and malabsorption.

Biliary Pancreatic Diversion with Duodenal Switch Surgery (BPD-DS): This surgery also involves a combination of restrictive and malabsorptive techniques. BPD-DS is a complex, 3-stage procedure that involves the following:

  • Removal of a large section of the stomach, so that it holds less food
  • Bypassing the upper part of the small intestine where most of the digestion takes place
  • And changing the normal function of bile in the digestion process

The goal of the surgery is to make you feel full quicker so you do not overeat, and absorb fewer calories by the modifications made in the small intestine and bile gland.

Indications for Malabsorptive Bariatric Surgery

Malabsorptive bariatric surgery is indicated for extremely obese patients who have not been successful in losing weight through conservative measures such as dieting, exercise, and medication.

Obesity is a chronic condition in which there is an excessive accumulation of fat in the body. Obesity is defined as a Body Mass Index (BMI) of 30 to 34.9 and extreme or morbid obesity is a BMI of 40 or more. Obesity is a global problem affecting people of almost all age groups and is associated with increased risk of cardiac problems, diabetes, high blood pressure, breathing difficulties, and other diseases.

You are a candidate for malabsorptive bariatric surgery if your BMI is greater than 50 or if you have a BMI of more than 40 with one or more obesity-associated complications.

Preparation for Malabsorptive Bariatric Surgery

In general, pre-procedure preparation for malabsorptive bariatric surgery may involve the following steps:

  • A thorough examination is performed by your doctor to check for any medical issues that need to be addressed prior to surgery.
  • Depending on your medical history, social history, and age, you may need to undergo tests such as blood work and imaging to help detect any abnormalities that could compromise the safety of the procedure.
  • You will be asked if you have allergies to medications, anesthesia, or latex.
  • You should inform your doctor of any medications or supplements that you are taking or any medical conditions you have such as lung or heart disease.
  • You may need to refrain from certain medications such as blood thinners or anti-inflammatories for a week or two prior to the procedure.
  • Refrain from smoking or alcohol for at least a couple of weeks before surgery and several weeks after surgery.
  • You should not consume any solids or liquids at least 8 hours prior to the procedure.
  • You should arrange for someone to drive you home after the surgery.
  • A signed informed consent will be obtained from you after the procedure has been explained in detail.

Procedure for Malabsorptive Bariatric Surgery

Malabsorptive bariatric surgery procedures include:

Gastric Bypass Surgery: This surgery is performed under general anesthesia. Your surgeon makes several small incisions on your abdomen.  A laparoscope, a thin instrument with a light and camera on the end, is inserted through one of the incisions, allowing your surgeon to clearly view the internal organs on a monitor. Small surgical instruments are inserted through the other incisions to perform the surgery. The first step is to reduce the size of the stomach so that it holds less food. The upper portion of the stomach near the esophagus is converted into a pouch by stapling. The second step of the surgery involves the creation of a bypass for food to flow from the new stomach pouch. The small intestine is divided into upper and lower segments. The lower segment of the small intestine (jejunum) is connected to the new pouch, while the upper segment (duodenum) is stapled closed. At the end of the procedure, the incisions are closed with sutures.

Biliopancreatic Diversion: BPD surgery can be performed by open or laparoscopic techniques. In the open method, a large incision is made in your abdomen. The laparoscopic method is performed through 4 to 5 small incisions. A laparoscope, a thin fiber-optic tube with a light and camera attached to its end, is inserted through one incision to view the internal organs. The camera allows your surgeon to clearly view the operating site on a monitor. Surgical instruments are inserted through the other tiny incisions to perform the surgery. In BPD surgery, the lower portion of the stomach is removed. The remaining part of the stomach is then attached to the ileum, the final segment of the small intestine, bypassing the first two portions of the small intestine. The incisions are closed upon completion.

Biliary Pancreatic Diversion with Duodenal Switch Surgery: BPD-DS surgery, a modification of BPD surgery, combines a sleeve gastrectomy (removal of part of the stomach) with a long intestinal bypass. The surgery can be performed by open or laparoscopic techniques and involves the following:

  • In the sleeve gastrectomy, part of the surgery, the outer margin of the stomach is removed, leaving a banana-shaped stomach, ¼ of its original capacity, that remains connected to the duodenum.
  • This creates a restrictive portion of the surgery. The surgeon accomplishes this by dividing the first part of the duodenum between the stomach and bile duct and closing of the divided end.
  • The surgeon then divides the small intestine about halfway down, connecting the lower portion to the open end of the duodenum.  This segment is referred to as the digestive, or roux, limb.
  • The remaining end of the small intestine is reconnected 75-100 cm from the large intestine creating the “common channel” allowing for bile and pancreatic juices to flow and mix with the food at the distal end of the small intestine, instead of in the duodenum, thereby limiting the absorption of nutrients and calories. 

Postoperative Care and Recovery

After the surgery, you are required to stay in the hospital for about 2 to 3 days. You will be given pain medications to keep you comfortable and antacids to reduce the amount of acid produced by your stomach. Your nurse will help you to move from your bed as frequently as possible to prevent the risk of blood clots. You will be kept on a liquid diet for the first few days, after which you will be slowly advanced to a pureed or soft diet. Your surgeon or dietician will give you a specific diet plan and instructions to follow thereafter. It is important to drink plenty of fluids throughout the day to avoid dehydration. Refrain from smoking and alcohol for a specific period of time as it can hinder the healing process. Refrain from strenuous activities and lifting anything heavier than 5 pounds for a defined period. Refrain from driving until you are fully fit and receive your doctor’s consent. A follow-up appointment will be scheduled to monitor your progress.

Risks and Complications

Malabsorptive bariatric surgery is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as:

  • Post-operative pain
  • Problems associated with anesthesia
  • DVT (blood clot in the deep leg veins)
  • Damage to the adjacent organs such as the spleen, pancreas, and bile duct
  • Abdominal hernia
  • Bleeding
  • Infection
  • Gallstone formation
  • Dumping syndrome
  • Dehydration
  • Malnutrition
  • Need for lifelong vitamin and mineral supplementation

Related Topics

American College of Surgeons American Society for Metabolic and Bariatric Surgery Society of American Gastrointestinal and Endoscopic Surgeons