Patients lose more than pounds and inches after bariatric surgery. Gastric bypass and gastric banding, the two most commonly performed procedures, have been shown to help resolve diabetes, eliminate sleep apnea and alleviate hypertension, among other potential secondary benefits. That evolution of care now makes bariatric surgery less a mechanical treatment for weight loss and more a metabolic therapy for the morbidly obese. Here's where the specialty stands now and where it may be heading.

The procedures
A gold standard surgical treatment doesn't exist, probably because we're not smart enough to predict the procedure that's best for a particular patient. Laparoscopic gastric bypass is currently the most commonly performed, followed by the increasingly popular adjustable gastric band procedure. Bilio-pancreatic diversion and the duodenal switch are current, but less popular, treatment options.

• Gastric bypass. The gastric bypass has been in existence for nearly 40 years. During that time, the procedure has undergone an evolution, transitioning to less invasive techniques. The majority of bypass surgeries are performed through 5-inch incisions. This has helped to increase the surgery's safety.

Although the approach to this operation has changed, the basic anatomical components have not. The stomach is partitioned to form a very small (less than one ounce) gastric pouch and the small intestine is connected to it, bypassing the duodenum. This effect, once thought to be mechanical (creating restriction by virtue of the size of the pouch and opening) and malabsorptive (decreased availability of calories) has been observed to alter gut hormones that affect satiety and diabetes. These observations have challenged our understanding of the mechanisms by which this and other operations exert their powerful effects, not only on weight loss, but on metabolic diseases.

Whatever the mechanism — restriction, malabsorption, increased satiety, aversion to sweets (dumping syndrome) — this operation works. Patients who've undergone gastric bypass not only have weight management superior to any non-surgical treatment, but also they live longer and have better control of their metabolic diseases.

• Laparoscopic adjustable gastric banding. The adjustable gastric band has been studied for more than 15 years. Recently, in a prospective randomized trial, the AGB has been shown to be superior to medical management of diabetes for patients whose body mass index is less than 35kg/m2.

The AGB has been shown to be a safe and effective treatment for morbid obesity, although absolute weight loss may not equal that of the gastric bypass or duodenal switch. However, it is an easier operation for surgeons to learn. It's often performed as an outpatient procedure and doesn't require stapling or cutting of the intestines. This, combined with an overall lower cost, makes it an appealing alternative to gastric bypass for patients.

However, success of the band is related to follow-up and adjustment of the device. Many patients travel to foreign countries to have this device implanted, only to discover that their band may not be FDA-approved in this country and, therefore, follow-up care here is not possible. The adjustable gastric band has secured its place in the treatment of morbid obesity.

• Biliopancreatic diversion and the duodenal switch. Although similar in theory, these operations have very different effects on the eating habits of patients. The biliopancreatic diversion is a highly malabsorptive operation; in fact, patients often eat more after the operation than before. Their diet is restricted, however, by side effects such as diarrhea and flatulence that result from dietary indiscretions. The duodenal switch, in contrast, has a more restrictive intake by virtue of the construction of the stomach tube and, therefore, often less malabsorption and dietary side effects compared with the biliopancreatic diversion.

These two operations are perhaps the most effective bariatric procedures when comparing absolute weight loss. However, they have a higher associated complication rate and mortality. Long-term follow-up and nutritional counseling are essential with these operations, similar to all bariatric procedures.

Expanded coverage — sort of
In November 2006 Medicare recognized bariatric surgery as a safe and effective treatment for obesity. It ruled that:

• Medicare will pay for the surgery for obese elderly (including those older than 65) or disabled patients who have tried but failed with other weight-loss options, have at least one weight-related medical problem and have a body mass index equal to or greater than 35kg/m2.
• Medicare will only pay for the surgery if patients undergo the procedure at centers that have been certified as Centers of Excellence by the American College of Surgeons or the American Society for Metabolic and Bariatric Surgery.
• The coverage will be limited to three of the most commonly performed types of stomach-shrinking surgery procedures: open and laparoscopic Roux-en-Y gastric bypass, open and laparoscopic biliopancreatic diversion with a duodenal switch and laparoscopic gastric banding. The vertical-banded gastroplasty is no longer a covered operation.

In expanding its coverage, Medicare made bariatric surgery available to many. But by ruling that surgeries are reimbursable only if performed in accredited Centers of Excellence, it also limited access for scores of other potential patients.

Surgeries should be performed in high-volume facilities by surgeons who can demonstrate safe and effective results. Reimbursing for procedures performed in Centers of Excellence is an important aspect of promoting the safe practice of bariatric surgery. But patients in rural or remote areas must forgo surgical intervention; travel to highly populated areas for access to a Center of Excellence or cover the cost of the procedure themselves.

Commercial payors often follow Medicare's lead, mandating a patient's meeting of certain criteria before paying for bariatric surgery. Some commercial payors, however, don't provide coverage, regardless of the facility's quality of service or the patient's need. Insurers have to make decisions based on finances, although a lively debate could center on the morality of not paying for a procedure that could stave off a life-threatening condition.

There are many barriers to care, even for insured patients. Many have to comply with requirements that have no scientific foundation, such as mandatory six-month weight loss programs, or travel to another city because of contractual issues. Imagine living in Los Angeles, finding out that you have a small breast cancer, but only being able to receive treatment in San Diego because they have secured a better contract for the "elective" lumpectomy.

Patients who have the means to secure financing for paying for operations do so if there are no alternatives. They do so for their health and quality of life. However, the treatment of morbid obesity should be a core benefit and available to all citizens. Morbid obesity is a killer. Surgical treatment shouldn't be considered "elective." Surgery saves lives.

Future growth
Potential weight-control treatments include implantable gastric stimulators that send "full" signals to the brain and a balloon implant placed in the stomach to limit food intake. These developments lack adequate clinical evidence, but could further the minimally invasive and outpatient treatment of the morbidly obese. They also offer the possibility of caring for patients who aren't dangerously obese, but who still might benefit from surgery to treat conditions related to excess weight. Patients might opt for low-risk surgical cures for hypertension and high cholesterol if they'll end a lifetime of drug therapy that simply keeps the conditions in check.