Laparoscopic sleeve gastrectomy for obesity

A summary of the ECRI Institute’s Emerging Technology Evidence Report

Sleeve gastrectomy is a surgical procedure that reduces the size and volume of the stomach, thereby restricting food intake while preserving the stomach’s function and enabling weight loss. Gastrectomy is known as a restrictive procedure in contrast to a malabsorptive procedure that inhibits food absorption. The surgery includes removal of the greater part of the stomach and many of the glands that produce the appetite-stimulating peptide, ghrelin. Postoperatively, the stomach resembles a slender tube, a “sleeve,” with a volume capacity of 60 to 200 mL. The procedure can be performed as open surgery or laparoscopic surgery.

Editor’s Note:

Managed care leaders are striving to make evidence-based decisions about new and emerging health technology. MANAGED CARE and ECRI Institute have collaborated to disseminate bimonthly summaries of the Institute’s Emerging Technology Evidence Reports. ECRI Institute is an independent not-for-profit organization that researches the best approaches to improving patient care. It does its work by analyzing the research literature and data on clinical procedures, medical devices, and drug therapies.

This summary provides a review of the literature through Nov. 10, 2010.

Most surgeons perform laparoscopic sleeve gastrectomy (LSG) to improve short-term operative and perioperative outcomes such as blood loss, adverse events (AEs), length of hospital stay, and patient recovery time. For patients with morbid obesity (body mass index [BMI] ≥35 kg/m2 with a comorbidity or BMI <40 kg/m2) or lesser obesity with serious comorbidity, LSG may be performed to enable adequate weight loss and reduce comorbidities while potentially causing fewer AEs than bariatric surgeries that result in greater reduction of the stomach size and/or malabsorption. For patients with super obesity (BMI ≥50 kg/m2), LSG may provide a feasible and safe first step, and the surgeon can perform the more technically demanding second-step procedure, laparoscopic biliopancreatic diversion with duodenal switch, 6 to 12 months later or once weight and related risks are sufficiently reduced.

Possible advantages of LSG over other bariatric surgery procedures include:

  • No foreign materials are introduced.
  • No digestive anastomosis is created.
  • No postoperative band adjustments are required.
  • Digestive tract is accessible to endoscopy after surgery.
  • Should not induce malabsorption or dumping syndrome.
  • Lower risk of inducing peptic ulcers.

Potential disadvantages of LSG include:

  • The procedure is complex in super obese men with large left liver lobes.
  • The procedure requires long staple lines that could leak.
  • A second operation may be needed if sufficient weight loss is not achieved.
  • The procedure permanently alters the stomach anatomy.

We focused our efficacy analysis on comparative effectiveness with other weight-loss procedures because evidence published to date has shown that laparoscopic sleeve gastrectomy induces substantial weight loss and clinical improvements.

Findings for each key question are:

1. How do clinical efficacy outcomes of LSG compare to other bariatric procedures?

No conclusions are currently possible regarding the comparative clinical efficacy of LSG because of the very small quantity of data, much of which came from small, low-quality studies.

An insufficient amount of evidence for each comparison was available to reach conclusions about how the effectiveness of LSG compares to other bariatric procedures.

One study compared excess weight loss after laparoscopic adjustable banding to LSG and did not find a significant difference. One study compared excess weight loss to endoscopic expandable intragastric balloon and did not find a significant difference (although the poor efficacy of LSG in this study compared to the efficacy of LSG in achieving weight loss in other LSG studies brings this into question). One study suggests that LSG may induce less weight loss than laparoscopic duodenal switch. Two studies compared LSG to laparoscopic Roux-en-Y gastric bypass, but the findings were conflicting, precluding any conclusions.

For resolution of comorbidities (e.g., hypertension, diabetes, elevated cholesterol levels), limited data suggest that LSG is not significantly different from intragastric balloon, banding, or Roux-en-Y. One study suggests no significant difference in the proportion of patients requiring additional bariatric surgery for weight loss after LSG or banding. For assessing quality of life after bariatric surgery, no data were available.

2. How do perioperative outcomes of LSG compare to other bariatric procedures?

An insufficient amount of evidence for each comparison was available to reach conclusions about how perioperative outcomes associated with LSG compare to other bariatric procedures.

Very limited data (one study for each comparison) suggest that length of stay for LSG is longer than for intragastric balloon or banding but shorter than for Roux-en-Y or duodenal switch surgeries. Since intragastric balloon placement is an endoscopic, and not a surgical, procedure, one might expect length of stay to be shorter than for LSG.

Operative time did not appear to be significantly different for LSG compared to banding based on data from only one study; another study suggests LSG operative time is shorter than for duodenal switch or Roux-en-Y surgery.

Blood loss was reported in only one study and was not clinically significant, ranging from about 7 percent to 20 percent of one pint [450 mL] of blood lost during surgery for LSG, Roux-en-Y, and duodenal switch. In the study, LSG was associated with the least amount of blood loss.

3. How do AE rates for LSG compare to those of other bariatric procedures?

No conclusions can be drawn regarding comparative safety because so few studies reported the same AEs. No single AE rate was statistically significantly different for LSG compared to other procedures, although only one or two studies addressed each comparison, and the size of these evidence bases may have been underpowered to detect differences between groups for rare events. One study did find the overall rate of harms and overall rate of major harms were significantly lower for LSG than for duodenal switch or Roux-en-Y bypass surgery, but no other studies reported AE rates in this fashion.

4. What AEs were reported for LSG?

The overall mortality rate was 0.9 percent for super obese patients and 0.2 percent for morbidly obese patients (including one suicide). The proportion of patients requiring reoperation for any reason was 3.5 percent in the super obese group and 2.3 percent in the morbidly obese group. The most common AE was leaking, which most frequently occurred perioperatively. However, at less than 2 percent, the rate was low. The other AEs occurred at rates of less than 1 percent overall. Super obese patients had several instances of serious events that were not reported in the lower BMI patients, such as need for ventilator support or development of renal failure.

Hospitals without previous bariatric surgery experience will need to invest in special equipment, including high-capacity beds, laparoscopic instrumentation for surgery on morbidly and super obese patients, patient lifts, and fluoroscopic imaging tools. In addition, this specialized equipment will likely require a significant increase in training for surgeons and other staff.

However, for hospitals that offer bariatric services, performing LSG instead of, or in addition to, other bariatric surgeries should not greatly affect hospital operations.

The U.S. Centers for Medicare & Medicaid Services considers LSG an uncovered service regardless of the patient’s BMI or comorbidity status. Of 11 representative commercial third-party payers that provide their coverage policies online, the policies of six payers indicate that LSG is covered (with some conditions). The policies of five payers describe noncoverage for LSG; most of these state that it is investigative. Effective January 2010, the American Medical Association assigned a Current Procedural Terminology code to describe LSG as a primary single-stage restrictive procedure. Establishing this code facilitates payment, but it does not guarantee coverage for the procedure.

Summary of the evidence base

Quantity of evidence base: low

Only one or two studies addressed each outcome for any comparison, providing an insufficient quantity of evidence to form conclusions about comparative effectiveness, safety, or perioperative outcomes. While including case series to assess adverse events increased the amount of included data to identify adverse events, very little information on long-term harms is currently available.

Quality of evidence base: low

Although three high-quality well-designed randomized controlled trials were included in the evidence base, most of the evidence (17 studies) comes from poorly designed nonrandomized controlled trials and case series.

Consistency of evidence base: low

For most efficacy and perioperative outcomes, only one study addressed the same outcome for the same comparison; therefore, consistency of outcomes among studies cannot be assessed. Body mass index change and percentage of excess weight loss were assessed in two studies of laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass, and the findings of those studies were very inconsistent.

Excerpted with permission from ECRI Institute’s database of Emerging Technology Evidence Reports. The complete report can be purchased from ECRI Institute’s Health Technology Assessment Information Service at

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