Obesity

Obesity is not solely a North American phenomenon. All areas of the world and all socioeconomic classes demonstrate a rapidly increasing prevalence of obesity. Obesity is defined as a body mass index (BMI, weight in kilograms divided by the square of the height in meters) greater than 30 kg/m². Morbid obesity is present at a BMI of 35 kg/m² in people who have weight-related comorbid conditions (i.e., hyperlipidemia, diabetes mellitus, obstructive sleep apnea, reactive airway disease) or a BMI of more than 40 kg/m² in the absence of weight-related comorbid conditions. Excessive caloric intake only partly contributes to obesity. Psychiatric, physiologic, and metabolic components are all likely factors that contribute to the obesity phenomenon. Emerging research identifying digestive hormones that influence eating behavior, metabolism, and weight gain (e.g., ghrelin, peptide YY) could potentially lead to nonsurgical therapies for obesity. However, at this time, only surgical interventions have been demonstrated to be effective in producing a significant sustained weight loss in the treatment of obesity.

Surgical procedures for weight loss

Current WLS involves restrictive or restrictive-malabsorption components. Restrictive procedures (adjustable gastric banding, gastric sleeve resection) create a small stomach but do not alter how food is digested. The most common restrictive procedure at this time is the laparoscopic adjustable gastric banding procedure. The U.S. Food and Drug Administration approved the adjustable gastric band for clinical use in 2001, and its application has increased annually since its introduction. In this procedure, a limited dissection of connective tissue is performed at the top of the stomach, and an inflatable band is passed that encircles the upper stomach (Figure 164-1, A). The band can be adjusted via a port attached to the body wall by adding or withdrawing saline. The surgical risk is considered to be very low. In select patients, this is being performed as an outpatient procedure.

The gastric sleeve resection is typically performed laparoscopically and reduces stomach volume to approximately 100 mL by externally stapling the stomach to exclude the fundus and greater curvature to form a narrow tube along the lesser curvature of the stomach (Figure 164-1, B). Both laparoscopic adjustable gastric banding and gastric sleeve resection procedures result in significant weight loss, providing that the patients receiving these interventions comply with proper eating habits, particularly those who avoid high-caloric content (e.g., milkshakes, candy, ice cream). Blood loss is minimal. Surgical duration is relatively brief. Complications are infrequent.