Obesity: Preventing and Managing the Global Epidemic – Report of a WHO consultation. Geneva, 3-5 June 1997, Section 10.5.5

Gastric Surgery

Surgery is now considered to be the most effective way of reducing weight, and maintaining weight loss, in severely obese (BMI > 35) and very severely obese (BMI > 40) subjects.  On a kg/weight loss basis, surgical treatment has been estimated after four years to be less expensive than any other treatment (82).

Surgical Procedures

A variety of different methods are available for the treatment of obesity.  These are generally based on two principles, restriction of energy intake and malabsorption of food.  Some surgical methods achieve a combination of both restriction and malabsorption effects.  However, there is now clear agreement that vertical banded gastroplasty, Roux-en-Y gastric bypass, duodenal switch and the use of certain laparoscopic techniques are among the procedures considered effective.  Full evaluation of long-term safety and efficacy is pending.  Intestinal (16, 83) bypass surgery is no longer recommended as a surgical option to treat obesity. 

Patient Selection

Improvements after surgery

Substantial weight loss of more than 20 kg generally occurs within 12 months of the operation, although some weight is regained within 5 to 15 years.  Analysis of patients from the SOS study in Sweden showed weight losses of 30-40 kg over two years depending on the surgical procedure used (84).

Surgical gastric bypass treatment ameliorates obesity-related morbidity in the majority of obese patients.  In the SOS study, surgical treatment remitted NIDDM in 68% of obese patients and hypertension in 43%.  For those who did not have risk factors at baseline, a 30-kg weight loss was associated with a 14-fold risk reduction for NIDDM, and 3- to 4- fold risk reductions with respect to the development of hypertension and other cardiovascular risk factors (84).  In addition, surgical treatment has been shown to prevent progression of impaired glucose tolerance to NIDDM (85).

Quality of life measures including employability, median wage, sick days, social interaction, mobility, self-image, assertiveness and depression are also improved in the majority of patients after anti-obesity surgery.  Recently, patients in the surgical intervention group of the SOS reported marked improvements in social interaction, perceived health, mood, anxiety, depression and obesity-specific problems compared to controls.

Risks associated with surgery

Risks associated with gastric surgery include micronutrient deficiencies, neuropathy, postoperative complications, “dumping syndrome”, and late post-operative depression (83).  It has been proposed, however, that most of the complications associated with this type of surgery, unlike most other surgery, are modifiable with behavior therapy.  Kral for example, notes that the vomiting seen in approximately 10% of patients after surgery is due more to eating behavior than to stenosis or stricture of the gastroplasty stoma (86).

Operative mortality in experienced centers is a fraction of the mortality observed in unoperated patients and in those remaining on waiting lists for operations (87).

Liposuction of unwanted subcutaneous fat depots is being used extensively for cosmetic reasons but offers no medical benefit in terms of co-morbidities linked to obesity.


 

References

 

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86.             Kral J.G., Side-Effects, Complications and Problems in Anti-Obesity Surgery.  International Journal of Obesity and Related Metabolic Disorders, 1994, 18(Suppl 2), 86.

 

87.             Kral J.G. Surgery. In: Guy-Grand B, ed. Management of Obesity and Overweight.  Background Paper Prepared by the IOTF’S Obesity Management Subgroup, 1996.

 

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