Gastric Bypass

This procedure is highly suited to performance through a laparoscopic approach. The open approach, however, is still used in many centers. Whether done open or laparoscopically, the steps of the procedure are the same. The operation can be divided into distinct steps: Step one, creation of the roux limb: The ligament of Treitz is identified; approximately 40 cm distal to the ligament is measured; the small bowel is divided at this position; the small-bowel mesentery is then divided; the small bowel to be bypassed, 75 cm-150 cm, depending on anatomy and amount of malabsorption, if any, desired, is then measured; the enteroenterostomy is constructed; and the defect in the mesentery closed. Step two, division of the omentum: The space between the roux limb and the transverse mesocolon — Peterson's space — a potential space for an internal hernia, is closed. Step three, creation of the gastric pouch: The avascular window in the gastrohepatic omentum is incised and opened along the lesser curve of the stomach, and the fatty and vascular tissue divided from the gastric wall, to create a 30 ml pouch; one transverse staple firing and two to three vertical firings create the pouch; the roux limb is then anastomosed to the pouch to complete the procedure; and a drain is placed across the upper anastomosis (Figure 7.2).

The long-term results of the Roux-en-Y gastric bypass on weight loss and improvement in obesity-related comorbidities have been described by a number of authors. Pories and colleagues43 have described their results over a 14-year period with a 97 percent follow-up in 608 morbidly obese patients. The mean weight loss was 49.2 percent (99.7 pounds) of excess body weight. A more striking finding in this study was the long-term control of adult-onset diabetes. Of 298 glucose-intolerant patients (146 with noninsulin-dependent diabetes mellitus and 152 with

FIGURE 7.2 Roux-en-Y gastric bypass. A Roux limb, created by dividing the proximal jejunum 40-60 cm distal to the ligament of Treitz, is anastomosed end-to-side to a 30-ml gastric pouch. The proximal jejunal (biliopancreatic) limb is anastomosed end-to-end to the Roux limb 75-150 cm distal to the gastroenterostomy.

impaired glucose tolerance), 271 (91 percent) maintained normal fasting glucose levels, glycosylated hemoglobins, and insulin levels. Of the diabetic patients, 80 percent were off all hypoglycemic agents. Although the mechanism remains unclear, the results have been reproduced in a number of shorter-term studies. In 353 patients with hypertension, only 85 (14 percent) remained hypertensive. Other studies report significant reductions in blood pressure, triglycerides, and low-density lipoproteins, with an increase in the plasma levels of high-density lipoproteins.44

Complications of open gastric bypass include splenic injuries (0.7 percent to 2.5 percent), anastomotic leaks (1.2 percent to 5 percent), seromas or superficial wound infections (11.4 percent to 14.5 percent), deep-wound infections (3 percent to 4.4 percent), deep venous thrombosis or pulmonary embolisms (0.6 percent to 2 percent), and a 30-day mortality rate of approximately 0.4 percent.45,46 Although the leak and coagulation complications remain with the laparoscopic approach, the wound problems and splenic-injury problems have declined significantly. Late complications include gastric-outlet stenosis and obstruction (3.4 percent to 14.6 percent), marginal ulcer (0.2 percent to 13.3 percent), small-bowel obstruction (4.7 percent), incisional hernia (4.7 percent to 23.9 percent), and symptomatic gallbladder disease (10 percent to 11.4 percent).47-49 The incisional hernia rate with the laparoscopic approach is significantly reduced. Nutritional deficiencies of iron, vitamin B12, folate, calcium, and the fat-soluble vitamins A, D, and E can occur without appropriate supplementation.

Currently Roux-en-Y gastric bypass is the gold standard weight-loss operation with good long-term follow-up studies.50

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