Obesity is a medical condition affecting more than 30% of the population in the United States. Obesity affects an individual's personal quality of life and contributes significantly to morbidity and mortality. Obesity is most commonly defined by body mass index (BMI), a measure which takes into account a person's weight and height to gauge total body fat. It is a simple, rapid, and inexpensive measure that correlates both with morbidity and mortality. Overweight is defined as a BMI of 25 to 29.9 kg/m2 and obesity as a BMI of 30 kg/m2. Morbid obesity is defined as BMI≧40 kg/m2 or being 100 lbs. overweight. Obesity and its co-morbidities are estimated to cost an excess of $100 billion dollars annually in direct and indirect health care costs. Among the co-morbid conditions which have been associated with obesity are type 2 diabetes mellitus, cardiovascular disease, hypertension, dyslipidemias, gastroesophageal reflux disease, obstructive sleep apnea, urinary incontinence, infertility, osteoarthritis of the weight-bearing joints, and some cancers. These complications can affect all systems of the body, and dispel the misconception that obesity is merely a cosmetic problem. Studies have shown that conservative treatment with diet and exercise alone may be ineffective for reducing excess body weight in many patients.
Bariatrics is the branch of medicine that deals with the control and treatment of obesity. A variety of surgical procedures have been developed within the bariatrics field to treat obesity. The most common currently performed procedure is the Roux-en-Y gastric bypass (RYGB). This procedure is highly complex and is commonly utilized to treat people exhibiting morbid obesity. In a RYGB procedure, a small stomach pouch is separated from the remainder of the gastric cavity and attached to a transected portion of the small intestine. This transected portion of the small intestine is connected between the “smaller” gastric pouch and a distal section of small intestine allowing the passage of food therebetween. The conventional RYGB procedure requires a great deal of operative time and is not without procedure related risks. Because of the degree of invasiveness, post-operative recovery can be quite lengthy and painful. Still more than 100,000 RYGB procedures are performed annually in the United States alone, costing significant health care dollars.
In view of the highly invasive nature of the RYGB procedure, other less invasive procedures have been developed. These procedures include gastric banding, which constricts the stomach to form an hourglass shape. This procedure restricts the amount of food that passes from one section of the stomach to the next, thereby inducing an early feeling of satiety. A band is placed around the stomach near the junction of the stomach and esophagus. The small upper stomach pouch is filled quickly, and slowly empties through the narrow outlet to produce the feeling of satiety. In addition to surgical complications, patients undergoing a gastric banding procedure may suffer from esophageal injury, spleen injury, band slippage, reservoir deflation/leak, and persistent vomiting. Other forms of bariatric surgery that have been developed to treat obesity include bilio-pancreatic diversion, vertical banded gastroplasty and sleeve gastrectomy. As aspects of some of these procedures, including RYGB, involve stapling a portion of the stomach, many bariatric procedures are commonly referred to as “stomach stapling” procedures.
For morbidly obese individuals, RYGB, gastric banding or another of the more complex procedures may be the recommended course of treatment due to the significant health problems and mortality risks facing the individual. However, there is a growing segment of the population in the United States and elsewhere who are overweight without being considered morbidly obese. These persons may be 20-30 pounds overweight and want to lose the weight, but have not been able to succeed through diet and exercise alone. For these individuals, the risks associated with the RYGB or other complex procedures often outweigh the potential health benefits and costs. Accordingly, treatment options should involve a less invasive, lower cost solution for weight loss. Further, it is known that modest reductions in weight may significantly decrease the impact of co-morbid conditions including, but not limited to type 2 diabetes mellitus. For this reason as well, a low cost, low risk procedure with effective weight loss results would provide significant benefit to both patients and health care providers.
Accordingly, it is desirable to have a low risk, minimally invasive procedure for treating obesity. It is desirable to have a procedure in which a treatment device can be easily and safely implanted into the gastric cavity of a patient to reduce the effective volume of the cavity. Additionally, it is desirable to have such a device that can assume an initial deploying configuration, and then be transformed into a second operable configuration within the gastric cavity. Further, it is desirable that the device apply outward pressure against the wall of the gastric cavity in the operable configuration in order to create a sensation of fullness within the patient. Further, it is desirable to have a method of treating obesity by reducing the effective volume within the gastric cavity. Additionally, it is desirable to have a method of treating obesity which includes applying pressure against the inside surface of the gastric cavity to create a feeling of fullness. It is desirable that the obesity treatment method be low cost and minimally invasive so as to be beneficial to a large number of obese patients. Further, it is desirable that the obesity treatment be easily and safely reversible. The present invention provides an implantable obesity treatment device and method of treating obesity which achieves these objectives.