http://www.radiologic.theclinics.com/article/S0033-8389(07)00005-X/abstract
Laura R. Carucci, MDa ; Mary Ann Turner, MDa ; Richard A. Szucs, MDa,b

Obesity is increasing in epidemic proportions and currently is the second leading cause of preventable death in the United States [1,2]. In the United States, more than 50% of adults are overweight, and more than 20% are considered obese. Furthermore, approximately 12 million Americans are considered morbidly obese as defined by a body mass index (BMI) greater than or equal to 40 kg/m2 [1,3,4]. Obesity is associated with serious medical comorbidities, and society pays a high cost for this condition in terms of health care dollars and obesity-related deaths [2,4–7]. Conservative measures to achieve weight loss, including diet, exercise, and behavioral modification, have a high failure rate in the setting of morbid obesity [1,4–8]. As a consequence, surgical approaches have been developed for patients who have failed conservative treatments. According to the criteria formulated in 1991 by the National Institutes of Health consensus development conference, bariatric surgery may be considered for patients who have a BMI of 40 kg/m2 or higher or of 35 to 40 kg/m2 with associated high-risk obesity- related comorbidities [5,6,9–11]. In addition, patients should have failed prior conservative methods of weight loss. Surgery for morbid obesity incorporates restrictive and/or malabsorptive procedures for the achievement of weight loss. One of the first bariatric procedures performed was the malabsorptive jejunoileal bypass. This procedure subsequently was abandoned because of severe metabolic and nutritional complications [5,7,8]. In more recent years, gastric restrictive procedures including horizontal and vertical gastroplasty and vertical banded gastroplasty have increased in prevalence. Other procedures such as the combined restrictive and malabsorptive Roux-en-Y gastric bypass (RYGBP) and the malabsorptive biliopancreatic diversion (BD) with or without duodenal switch also have increased in prevalence [5,8]. The RYGBP and BD are now the most commonly performed bariatric procedures in the United States and Canada, comprising 80% to 90% of bariatric procedures [12]. However, restrictive procedures remain the most popular surgical option in European countries [12–14].

Restrictive procedures work by limiting the volume of solid food that can be consumed, but liquid and semisolid high-caloric foods may pass without the sensation of satiety [12]; therefore, patient cooperation is required to maintain a restricted diet and to avoid overfeeding [12,14]. On the other hand, combined restrictive and malabsorptive bariatric procedures, such as RYGBP, result in greater sustained weight loss with less need for patient compliance; however, these procedures are more technically demanding and have higher overall morbidity [1,7,12,15]. Technically, restrictive bariatric procedures are easier to perform and have lower complication rates than RYGBP and BD; however, restrictive procedures may not be as successful for long-term weight loss, especially in superobese patients (BMI > 50 kg/m2) [2,12,14–16]. Success rates for gastric restrictive procedures are better in Europe than in the United States, possibly related to differences in diet and less severe obesity in Europe [12,17]. Indeed, patients undergoing bariatric surgery in the United States tend to have a higher BMI, with more patients in the superobese category than in European countries [12]. A restrictive gastric banding procedure was first introduced in 1983, was made adjustable in 1986, and was made available laparoscopically in the early 1990s [5,8,18–20]. Because classic bariatric procedures are associated with a high complication rate and numerous side effects, the concept of a reversible, adjustable gastric banding device has become a popular alternative to more traditional bariatric procedures [21,22].