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A Review of Bariatric Surgery Procedures to Induce Weight Loss

Sherry Haynes is currently pursuing a PharmD degree and has experience in both the clinical and management sides of pharmacy.

Bariatric surgery results in significant weight loss and helps prevent more than 40 diseases related to obesity.

It causes weight loss either by restricting the amount of food intake, causing malabsorption of calories and nutrients by bypassing the part of the intestine that absorbs the most food, or by a combination of these. Restriction of food intake is achieved by reducing the size of the stomach with a gastric band or by removing a part of the stomach so that the person feels full earlier. Most of the bariatric operations are successfully performed laparoscopically—through multiple, small incisions.

Common bariatric surgery procedures are:

  1. Gastric Banding
  2. Roux-en-Y Gastric Bypass
  3. Biliopancreatic Diversion With Duodenal Switch (BD/DS)
  4. Sleeve Gastrectomy
  5. Mini-Gastric Bypass
  6. Gastric Plication (Gastric Imbrication)

Most types of bariatric surgery require the patient to take long-term vitamin and iron supplementation. In the immediate weeks following surgery, the patient will be restricted to an all-liquid diet.

1. Gastric Banding

Diagram of the gastric banding procedure.

Diagram of the gastric banding procedure.

Laparoscopically adjustable gastric banding (LAGB) is the least invasive of all surgical interventions currently available. It was the first surgery performed laparoscopically. It does not require removal of tissue or any alteration of gastric or intestinal continuity.

A constricting ring is placed around the top end (fundus) of the stomach. The band has an inflatable balloon within its lining to allow for adjustment of the size of the stomach to regulate food intake. Additional surgery is not needed for adjustment; adjustment is performed by adding or removing saline through a subcutaneous access port to fill or empty the balloon. This is technically a reversible procedure.

Complications associated with the gastric banding procedure:

  • Splenic injury
  • Oesophageal injury
  • Wound infection
  • Band slippage
  • Band migration or erosion
  • Persistent vomiting
  • Poor nutrition
  • Scarring inside the belly

Other risks:

  • Acid reflux
  • Failure to lose weight

Patients will be required to eat slowly, eat only when hungry, and to eat only until no longer hungry, not until completely full. The average hospital stay for gastric banding is generally less than a day.

2. Roux-en-Y Gastric Bypass (RYGB)

Diagram of a Roux-en-Y gastric bypass.

Diagram of a Roux-en-Y gastric bypass.

It is the most commonly performed and is considered the gold standard for bariatric surgery procedures. It combines restriction and malabsorption techniques.

The upper part of the stomach is partitioned and surgically stapled to create a small pouch (restriction). The pouch has a small outlet which opens to the middle of the small intestine. The duodenum and jejunum of the small intestine are bypassed to limit the absorption of the calories (malabsorption).

A gastric bypass can technically be reversed.

Complications associated with gastric bypasses:

  • Failure of stapled partition
  • Leakage at the junction of the stomach and small intestine
  • Acute gastric dilation
  • Delayed gastric emptying—spontaneously or due to a blockage
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Complications after a surgery:

  • Vomiting
  • Wound hernias
  • Intestinal obstruction
  • Dumping syndrome: It is thought that dumping syndrome helps patients lose weight by conditioning them against eating sweet foods.
  • Nutritional deficiencies: Calcium, vitamin D, vitamin B12, and iron deficiency anemias. Routine monitoring of nutrition and frequent supplementation is required.

3. Biliopancreatic Diversion With Duodenal Switch (BPD/DS)

Diagram of a biliopancreatic diversion.

Diagram of a biliopancreatic diversion.

The stomach is divided vertically—preserving the pylorus—and stapled. The small intestine is cut into the alimentary limb and the biliopancreatic limb. The stomach empties the food into the alimentary limb, where the essential nutrients get absorbed. The biliopancreatic limb coming from duodenum conveys bile and pancreatic juice to the common limb, where the digestion and absorption of fat/starch will take place. The common limb, which allows the delayed meeting of biliopancreatic secretion with food, is a characteristic of the biliopancreatic division.

For patients who undergo biliopancreatic diversion with duodenal switch, eating larger meals are allowed. After the surgery, a less restrictive (free) diet is allowed. Due to the complications associated with BPD/DS, it is used only in severely obese patients.

Risks of biliopancreatic diversion:

  • Protein-energy malnutrition
  • Iron and calcium deficiency
  • Vitamin A and vitamin E deficiency
  • Intestinal obstruction resulting from internal hernias
  • Bleeding
  • Pulmonary embolism
  • Anastomotic ulcer
  • Cholelithiasis

4. Sleeve Gastrectomy

Diagram of a sleeve gastrectomy.

Diagram of a sleeve gastrectomy.

This is the second most performed bariatric procedure after the RYGB. The stomach is divided vertically to preserve the pylorus (lower end), creating a tube or banana-shaped pouch along the lesser curvature, and then surgically stapled. The stomach size is reduced by 75-80%.

For some, a sleeve gastrectomy is enough to induce satisfactory weight loss, while in others, it is followed by a conversion to either a gastric bypass or a duodenal switch after 6 -12 months of the initial surgery.

The surgery is relatively quick to perform. Since the digestive process is unaltered, the complications of this surgery are relatively reduced.

This procedure is not reversible.

Sleeve Gastrectomy With a Loop Duodenojejunal Bypass

This is a single-anastomosis BPD-DS, also called as loop duodenal switch or stomach intestinal pylorus-sparing (SIPS). Single-anastomosis means there is a single surgical connection involved. It is a combination of a sleeve gastrectomy and a mini-gastric bypass. The middle of the jejunum is attached to the first part of duodenum in a loop fashion. This increases the hormonal changes responsible for weight loss and diabetes resolution.

Risks of a sleeve gastrectomy:

  • Gastritis
  • Heartburn
  • Ulcers
  • Injury to the stomach, intestine, or other organs during surgery
  • Leakage along the stapled line
  • Poor nutrition
  • Scarring inside the belly that can lead to future blockage of the bowel
  • Vomiting due to accidental overeating

5. Mini-Gastric Bypass

Diagram of a mini-gastric bypass, also known as a single-anastomosis bypass or an omega loop gastric bypass.

Diagram of a mini-gastric bypass, also known as a single-anastomosis bypass or an omega loop gastric bypass.

A small pouch is created in the stomach and stapled. All of the duodenum and a part of the jejunum—which is about 5-7 feet—is bypassed and attached to the small pouch using a surgical stapler. This is called anastomosis.

The new mini-stomach holds 4-6 oz of food. Once food leaves the mini stomach, it bypasses the duodenum and a part of jejunum and travels along the other part of the small intestine, restricting the number of calories absorbed by the body. However, digestive juices from the larger part of the stomach which no longer holds foods and biliopancreatic juices will still pass through the duodenum and meet the food at the bypass point to help the digestion.

Operating time is generally around 89 minutes. The hospital stay for a mini-gastric bypass, on average, is two days.

Risks of a mini-gastric bypass:

  • GI bleeding
  • Leakage
  • Abdominal bleeding
  • Bile reflux
  • Anastomotic ulcers caused when the small pouch of the stomach continues to secrete acids.
  • Iron deficiency
  • Protein malnutrition
  • An internal hernia
  • Regained weight
  • Cancer

6. Gastric Plication (Gastric Imbrication)

The gastric plication is a relatively new procedure that reduces the stomach volume without any removal of the stomach tissue. In this procedure, the stomach is folded into itself and stitched to create a narrow tube shape stoma (opening), similar to that of the sleeve gastrectomy procedure.

Hospital stay for a gastric plication is typically one or two days.


What is a revisional surgery?

Revision surgery is any bariatric surgery performed on a patient who already had a bariatric surgery in the past. It is a corrective surgery that is performed to correct an anatomical complication, like a fistula, stricture, or blockage, or to reverse or convert a procedure. For example, you can convert a sleeve gastrectomy to a gastric bypass for weight regain or to prevent heartburn.

How much does a typical bariatric surgery cost?

The cost of bariatric surgery may differ depending on the type of procedure and the surgeon performing the procedure. For example, Roux-en-Y gastric bypasses cost anywhere from $25,000 to $30,000. The cost includes the procedure and preoperative, intraoperative, and postoperative services. Gastric banding, on average, costs $15,000 to $20,000.

Who is eligible for bariatric surgery?

The 2014 Interdisciplinary European Guidelines on Metabolic and Bariatric Surgery indicates that bariatric surgery is generally approved for morbidly obese patients fulfilling the following criteria:

  • BMI > 40 kg/m2 with at least one comorbidity (e.g. sleep apnea, hypertension, insulin resistance, etc.)
  • Followed organized, weight-reducing attempts in a specialized center for at least 6 months.
  • Skeletal and developmental maturity.
  • Capable of committing to comprehensive medical and psychological evaluation pre- and post-surgery.
  • Willing to participate in a postoperative multidisciplinary treatment program.
  • Another recently proposed selectional criterium includes patients with BMI > 34 kg/m2 and serious comorbidities (type 2 diabetes mellitus, moderate or severe obstructive sleep apnea, severe steatohepatitis, etc.).

For More Information

If you want to learn more about bariatric surgery or maybe clear any misconceptions before planning to undergo one, Dr. E's Guide to Weight Loss Surgery is a book I came across sometime ago that answers all the questions in easy terms that are understandable to everyone—even those not familiar with the medical field. To give you an idea, some of the questions answered in this book are:

  1. Which is better for me, sleeve gastrectomy or gastric bypass?
  2. What do I do with the excess skin after surgery?
  3. What kind of tests do I have to have before surgery?
  4. How should I choose my surgeon?
  5. Can I get pregnant after surgery?


  1. Angrisani, L., Formisano, G., Santonicola, A., Hasani A., & Vitiello, A. Bariatric surgery worldwide. Bariatric and Metabolic Surgery. New York: Springer, 2017, pp. 19–24.
  2. Angrisani, L., Santonicolo, A., Iovino, P., Formisano, G., Buchwald, H., Scopinaro, N. (2015). Bariatric Surgery Worldwide 2013. Obes Surg. 25(10):1822-1832. doi: 10.1007/s11695-015-1657-z.
  3. Fried M. et al. (2014). Interdisciplinary European Guidelines on Metabolic and Bariatric Surgery. Obes Surg 24(1):42–55. doi: 10.1007/s11695-013-1079-8
  4. Maciejewski ML, Arterburn DE. (2013). Cost-effectiveness of Bariatric Surgery. JAMA, 310(7): 742-743. doi: 10.1001/jama.2013.276131

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2018 Sherry Haynes


CaribTales on February 25, 2018:

Thanks for this detailed explanation of the procedure. Seen the ads and wondered about it. Glad for those who have been and can be helped.

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