What is the efficacy of gastric bypass bariatric surgery?

Updated: Feb 16, 2021
  • Author: Alan A Saber, MD, MS, FACS, FASMBS; Chief Editor: John Geibel, MD, MSc, DSc, AGAF  more...
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After gastric bypass surgery, some patients may experience dumping syndrome upon ingestion of sweets. This is caused by the rapid passage of gastric pouch contents directly into the small bowel, unimpeded by a pyloric valve. The presence of concentrated simple sugars in the Roux limb presents a substantial osmotic load that may result in cramping and abdominal discomfort; additionally, the ensuing rapid release of insulin by the pancreas may cause symptomatic hypoglycemia. This unpleasant reaction to sugar is considered to be a desired effect of gastric bypass surgery, and it has been referred to by patients as the postoperative police officer.

Weight loss after gastric bypass has been shown to be greater than that obtained by dietary, medical, behavioral, or combined approaches to weight loss.

A long-term follow-up study performed by MacLean et al defined postoperative success as a reduction in weight to a BMI of less than 35 kg/m2. [12] By this criterion, a successful outcome was achieved in 93% of patients with an initial BMI of less than 50 kg/m2 and in 57% of patients with an initial BMI of greater than 50 kg/m2.

Since its initial description in 1994 by Wittgrove et al, laparoscopic gastric bypass has been shown to combine the efficacy of the open approach with the decreased pain, lower wound morbidity, and shorter convalescence of a minimally invasive procedure. [13] Results of several laparoscopic gastric bypass series have paralleled or improved upon those of open surgery.

In Higa's series of 400 laparoscopic procedures, patients lost an average of 69% of their initial excess weight by 12 months after the procedure. [14] Schauer's group reported even better weight loss; a group of 275 patients undergoing laparoscopic gastric bypass lost an average of 83% of excess weight at 24 months after surgery.

A prospective, randomized trial was completed that compared the results of laparoscopic gastric bypass to the results of open gastric bypass. Patients who had undergone laparoscopic gastric bypass were found to have substantially less impairment of pulmonary function after surgery and decreased postoperative pain.

In the author's experience, convalescence after laparoscopic gastric bypass is substantially reduced relative to open procedures, with some patients returning to work in 2 weeks or less.

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