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).
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.
Patients
should be selected for surgery according to the following principles:
Non-surgical
treatment including dietary measures and weight reducing drug therapy should
be tried first.
Surgery with gastric placation procedures should be used only on well-informed and motivated patients with acceptable operable risks.
Patients
should have a BMI > 40 or > 35 together with high-risk,
life-threatening co-morbid conditions.
Surgery
should be undertaken only by an experienced surgeon in an appropriate
clinical setting which incorporates expert medical surveillance, access to
ventilator facilities and the support of a multi-disciplinary team.
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 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.
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