Highlights from the annual scientific assembly: mechanisms to stop the epidemic of obesity: surgical therapy for obesity *. (Special Feature).

OBESITY IS a serious problem in the United States, and surgical therapy for obesity is an increasingly common and accepted medical practice. Various types of surgical procedures are available.

A Roux-en-Y gastric bypass is shown in Figure 1. This surgery is associated with loss of two thirds of excess weight (or one third of total weight) within 2 years after surgery; within 6 months of surgery, two thirds of this weight loss has been attained. The Roux-en-Y gastric bypass has been found to be significantly more effective for weight loss than various other types of gastroplasty procedures, including the vertical banded gastroplasty (Fig 2), in several randomized prospective trials and retrospective studies (Figs 3 and 4). Superobese patients with a body mass index >50 kg/[m.sup.2] have been shown to have improved weight loss with a 150 cm Roux limb, called a long-limb gastric bypass.

The mortality rate for gastric bypass surgery averages around 1%, and the rate is higher in massively obese patients, especially those with obesity hypoventilation syndrome. Roux-en-Y gastric bypass surgery may be associated with iron deficiency anemia, vitamin [B.sub.12] deficiency, and calcium deficiency; however, these can usually be prevented with prophylactic supplementation. All of the obesity operations can now be done laparoscopically, which has increased patient acceptance of the procedure. The Food and Drug Administration has recently approved implantation of a laparoscopically adjustable silicone gastric band. This device is equivalent to a gastroplasty procedure. We have found this to provide inadequate weight loss for the majority of our patients in whom we placed the band, especially the African American patients. Furthermore, it was associated with problems of esophageal dilatation, dysphagia, and band slippage. Band erosion into the stomach occurs in about 2% of patients. A more malabsorptive bariatric operation that has increased in popularity is the partial biliopancreatic bypass with duodenal switch. This operation may be associated with protein-calorie malnutrition, calcium deficiency, and fat-soluble-vitamin deficiencies (vitamins A, D, E, and possibly K). No randomized, prospective trials have compared the duodenal switch with a long-limb gastric bypass; however, the proponents believe it to be associated with a better, longer-lasting weight loss.

Surgically induced weight loss is associated with significant improvements in obesity comorbidity, usually within months of the surgery. Sleep apnea resolves or improves so that most patients are able to discontinue nasal continuous positive airway pressure (CPAP). Obesity hypoventilation is associated with normalization of arterial blood gases and elevated cardiac filling pressures. Type 2 diabetes mellitus resolves in 85% to 90% of patients, and systemic hypertension resolves in 66% to 75% of patients. Acid reflux disappears in most patients after gastric bypass surgery but may be aggravated by gastroplasty or gastric banding. Urinary incontinence resolves in 95% of patients. Low-density lipoprotein cholesterol falls, and high-density lipoprotein cholesterol rises. Pseudotumor cerebri resolves in 90% of patients with decreased cerebrospinal fluid pressures. Most venous stasis ulcers heal. Female sex hormone balance is improved, and previously infertile women may conceive. Degenerative joint disease of the b ack, hips, knees, and feet may improve but often does not resolve, since damage to the cartilage often precedes obesity surgery. Comorbidity improvement remains as long as the weight loss is maintained. Weight regain, seen in approximately 15% of patients, will be associated with comorbidity recurrence. Patients who correct their diabetes mellitus and hypertension lose more weight than those who do not. The Swedish Obesity Study (SOS) noted improvements in sick-leave time, quality of life, diabetes mellitus, and hypertension in the surgically treated patients, compared with matched patients treated in community medical clinics. The improvements in diabetes mellitus (47%) and hypertension (42%) were less than in the American studies, however. The weight loss (23% of body weight) in the SOS (using mostly gastroplasty and banding procedures) is less than with gastric bypass (35% of body weight). The SOS found recurrence of hypertension with weight regain at 7 years after surgery, which was not seen in the gastri c bypass surgery studies or in their own patients who had gastric bypass in Sweden. Central (android) obesity is associated with visceral fat induced hyperglycemia, hyperinsulinemia, and hypercholesterolemia. We have shown that central obesity causes a significant increase in intra-abdominal pressure (as measured by urinary bladder pressure) and is probably the cause of urinary incontinence, acid reflux, obesity hypoventilation, venous stasis disease, pseudotumor cerebri, and increased risk of incisional hernia. We also believe it is the cause of systemic hypertension in obesity.

[FIGURE 3 OMITTED]

[FIGURE 4 OMITTED]

Suggested Reading

1. Sugerman HJ, Starkey JV, Birkenhauer R: A randomized prospective trail of gastric bypass versus vertical banded gastroplasty for morbid obesity and their effects on sweets versus non-sweets eaters. Ann Surg 1987; 205:613-624

2. Sugerman HJ, Londrey CL, Kellum JM, et al: Weight loss with vertical banded gastroplasty and Roux-en-Y gastric bypass for morbid obesity with selective versus random assignment. Am J Surg 1989; 157:93-100

3. Pories WJ, Swanson MS, MacDonald KG, et al: Who would have thought it? an operation proves to be the most effective therapy for adult-onset diabetes mellitus. Ann Surg 1995; 222:339-350

4. carson JL, Ruddy ME, Duff AE, et al: The effect of gastric bypass surgery on hypertension in morbidly obese patients. Ann Intern Med 1994; 154:193-200

5. Sugerman HJ, Felton WL, Sismanis A, et al: Effects of surgically induced weight loss on idiopathic intracranial hypertension in morbid obesity. Neurology 1995; 45:1655-1659

6. Gleysteen JJ, Barboriak JJ, Sasse EA: Sustained coronary-risk-factor reduction after gastric bypass for morbid obesity. Am J Clin Nutr 1990; 51:774-778

7. Bjorntrop P: Abdominal obesity and the metabolic syndrome. Ann Med 1992; 24:465-468

8. Sugerman HJ, Windsor ACJ, Bessos MK, et al: Abdominal pressure, sagittal abdominal diameter and obesity comorbidity. J lntern Med 1997; 241:71-79

9. Sugerman HJ, Windsor A, DeMaria E, et al: Effects of surgically induced weight loss on urinary bladder pressure, sagittal abdominal diameter, and obesity comorbidity. Int J Obesity Metab Disord 1998; 2:230-235

* Presented as a Symposium at the 95th Annual Meeting of the Southern Medical Association, November 8-10, 2001, Nashville, Tenn.

Dr. Sugerman is the David M. Hume Professor of Surgery, Chief, General/Trauma Surgery Division, Vice Chairman, Department of Surgery, Medical College of Virginia of Virginia Commonwealth University, Richmond.

Southern Medical Association acknowledges Roche Laboratories for an unrestricted educational grant in support of this session, and appreciates their commitment to medical excellence.