Obesity surgery

Published on 09/04/2015 by admin

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Last modified 09/04/2015

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Chapter 27 OBESITY SURGERY

• Morbid obesity is increasingly prevalent in all developed and developing countries.

• Bariatric (weight-loss) surgery is the only treatment shown to cause measurable weight loss in those severely affected.

• Appropriately performed surgery in appropriately selected patients leads to weight loss, resolution of obesity-related comorbidities, reductions in medical and disability costs and reduced mortality risk.

• Other than the intragastric balloon, all surgical procedures aim to cause permanent changes in gastrointestinal physiology to encourage the durability of weight loss.

• Complications after this type of surgery can occur at any time post-procedure, and can be predicted by the procedure undertaken.

• Endoscopy has an important role to play, and these patients will present to gastroenterologists for care.

• Therapy for these patients cannot be accomplished without an understanding of the underlying anatomy.

DEFINITIONS OF OBESITY

The increasing prevalence of obesity is a worldwide phenomenon and it is a disease with protean adverse physical, social and psychological effects. The classification of obesity defines the relationship between a person’s height and weight, the body mass index (BMI) to stratify patients according to their risk of obesity-related medical conditions (Table 27.1).

TABLE 27.1 Obesity definitions ^*

	BMI (kg/m²)	Obesity class
Underweight	<18.5	–
Normal	18.5–24.9	–
Overweight	25.0–29.9	–
Obesity	30.0–34.9	I
Obesity	35.0–39.9	II
Extreme obesity	40.0+	III

* The term ‘morbid obesity’ relates to BMI 35.0–39.9 with medical comorbidities or BMI 40 and above.

TREATMENT OF OBESITY

There are many dietary, medical and therapeutic options available to clinicians treating patients with obesity and, in general, many of these treatments have been attempted by patients as they progress through various stages of their disease. Non-surgical treatments combining elements of diet, exercise and pharmacotherapy are demonstrated in the published literature to be effective in obtaining modest weight loss and perhaps allowing patients to ‘hold’ their weight, but have no long-term efficacy in those in whom massive sustained weight-loss is required. In general, weight-loss after surgical treatments is 5–10 times greater than that obtained by non-surgical methods, and the results in obesity comorbidity resolution, cost saving and mortality reduction cannot be matched by other methods.

Having surgery entails taking on some risks, so it is obvious that this is not a treatment that can be applied liberally. The effects of any operation, both positive and negative, may be permanent and some complications may develop insidiously many years later and, therefore, may not be related to the operation. Current, generally accepted criteria for selecting patients for surgery are listed in Table 27.2.

TABLE 27.2 Selection criteria for bariatric surgery

Body weight	BMI >40
	BMI 35–39.9 with medical comorbidities
	No endocrine cause
Resistant obesity	Obesity present >5 years
Resistant obesity	Multiple failed non-surgical attempts
Psychological profile	No alcohol or drug use
	No or controlled psychiatric conditions
	Understanding of surgery and commitment to follow-up

Weight-loss surgery

Obesity is a chronic, probably life-long disease and, therefore, the current surgical solutions are designed to cause permanent alterations to gastrointestinal physiology. These physiological alterations, while necessary for the maintenance of weight-loss, may become disordered and lead to the patient presenting for medical or surgical care. There are a range of bariatric surgical procedures currently undertaken, and a number of historical procedures that remain of interest due to the large number of patients who have undergone them in the past. Thankfully there is sufficient homology between all of the historic and current procedures to allow them to be grouped into categories when discussing them. Complications following surgery may be related to weight loss itself (e.g. gallstones), anatomic changes (e.g. vomiting, obstruction) or altered nutritional status (e.g. decreased intake, decreased absorption or gastrointestinal losses). Most of the subtle nutritional complications that can arise after this type of surgery are beyond the scope of this chapter and will not be discussed.

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