Surgery for obesity (Bariatric surgery) is not a new field but has been around for over 50 years. The first significant gastrointestinal operative procedures for weight loss were the intestinal bypasses. These procedures, first described in the 1950’s, involved the connecting (anastomosing) of the very proximal piece of the small intestine called the jejunum to the very distal part of the small intestine called the ileum, or even the colon. In doing so, approximately 90% of the small intestine’s absorptive surface area was no longer exposed to nutrients taken in. Although intestinal bypasses were successful for achieving significant weight loss, it came at the high price of significant complications. Patients universally suffered from chronic diarrhea and foul smelling flatus. Additionally many suffered from protein malnutrition, vitamin and macronutrient deficiencies, joint and muscle aches, and renal stones. Most troublesome, some patients developed cirrhosis and even liver failure. After decades of use, these procedures were no longer performed. In 1979, Dr. Nicola Scopinaro introduced a redesigned intestinal bypass called the “biliopancreatic diversion.” This procedure delivers significant weight loss results and does not have many of the severe long term consequences of the intestinal bypasses. A more recent variant is the biliopancreatic diversion with duodenal switch, or just “duodenal switch” for short (Figure 4). However, the complexity of these procedures and the risk of protein, vitamin, and mineral deficiencies have limited them to less than 5% of all bariatric procedures performed.
In the mid 1960’s, Dr. Edward Mason described the first experience with gastric bypass for weight loss. This procedure was thought to be much safer than the intestinal bypass because it had minimal if any malabsorption. The main mechanism of action was the restriction of nutrient intake by the creation of a very small gastric pouch which was connected directly to the intestine thereby “bypassing” the vast majority of the stomach and the proximal small intestine. At that time, the gastric bypass was a formidable operation in obese patients. In response, less complicated gastric restrictive procedures were developed. These procedures were known as “gastroplasties” and were very popular in the 1970’s and 1980’s. These procedures partitioned the stomach typically with surgical stapling devices to create small stomach pouches. Although safer and less complex than the gastric bypass, the results were inferior and these procedures declined in popularity. In the mid 1990’s, the gastric bypass was first successfully performed laparoscopically (Figure 2). The ability to now perform gastric bypasses laparoscopically, significantly reduced the operative complications, increased the acceptability of the gastric bypass.
In addition to the introduction of laparoscopy, there was another major advance and that was the introduction of the laparoscopic adjustable gastric band (Figure 1). This relatively simple and safe procedure behaved like a gastroplasty in that it creates a small gastric pouch but did so without staple-partitioning the stomach. The procedure has a very low complication rate. Another beneficial feature of the band is its adjustability. The band can be tightened or loosened in a simple office procedure thereby allowing the band to be uniquely adjusted for each individual patient. Band popularity sky rocketed worldwide but has recently diminished due to inferior results compared to the gastric bypass and also to the introduction of a new procedure known as the sleeve gastrectomy (Figure 3).
The sleeve involves the removal of the outer crescent of the stomach leaving behind a very small stomach remnant that holds only a few ounces. The sleeve has become very attractive for patients wanting good results with less of the risk and complexity of the gastric bypass.
Currently, patients considering bariatric surgery have the choice of four bariatric operative procedures; the laparoscopic adjustable gastric band (Figure 1), roux-Y gastric bypass (Figure 2), sleeve gastrectomy (Figure 3), and the biliopancreatic diversion with or without duodenal switch (Figure 4).
|Figure 1. The Laparoscopic Adjustable Gastric Band||Figure 2. Roux-Y Gastric Bypass|
|Figure 3. Sleeve Gastrectomy||Figure 4. Biliopancreatic Diversion With or Without Duodenal Switch|
As a further testament to the drive for safety, in the mid 2000’s, the American Society for Metabolic and Bariatric Surgery established a “Centers of Excellence Program” to insure that high standards for safety and quality of care were followed universally not just at certain centers. Shortly thereafter, the American College of Surgeons created a similar program. Between both entities, the vast majority of bariatric surgery programs in the U.S. are designated as “Centers of Excellence” and practice bariatric surgery at high levels of competence.
The current requirements for qualification for bariatric surgery have not changed in over 20 years. These requirements were established by the National Institutes of Health (NIH) in the 1991 NIH Consensus Statement. At the time, the only operative procedures being performed were the gastric bypass and the vertical banded gastroplasty. Based on the best available evidence at that time, the panel considered the potential risks of surgery against possible benefits and established the minimum criteria for considering patients for surgery as the following: a body mass index (BMI) of 35-39 kg/m2 if they suffer from obesity-related comorbidities, and a BMI >40 kg/m2, regardless of the presence or absence of comorbidity. Candidates for surgery should have failed attempts to achieve sustainable weight loss with nonoperative strategies (although no specific weight loss method was required). Some health insurance companies mandate that their clients must complete a structured preoperative weight loss program before authorizing coverage for surgery. They often stipulate that the program be “physician-supervised” and include monthly visits for a duration of 3 to 6 months. The value of such a requirement is debatable.
Although these standards have changed little in over 2 decades, much has changed in the field. As mentioned above the introduction of laparoscopy and new procedures such as the band and sleeve have dramatically reduced bariatric surgery complications. Given these observations and the growing evidence of the benefits of surgery for the treatment of conditions such as type 2 diabetes mellitus, many bariatric surgeons and a growing number of non-bariatric surgeon clinicians support allowing patients with type II diabetes and BMI > 30 kg/m2 to consider bariatric surgery. A small but growing body of literature also supports this consideration.
The most remarkable aspect of bariatric surgery is the fact that after surgery, weight loss is only one of the dramatic benefits realized by patients. Currently all of the conventional operative procedures can result in meaningful and sustainable weight loss. The range in weight loss varies with the procedure from a low of approximately 40% of excess achieved by the band to about 75% of excess for the realized by the duodenal switch. Additionally, the majority of patients will maintain significant weight loss for long term duration.
Even potentially more significant than the weight loss, is the improvement and even resolution of a large number of obesity-related health issues and diseases such as type II diabetes mellitus, hypertension, and sleep apnea, just to name a few.
Several long term studies have also discovered that bariatric surgery may reduce the risk of several types of cancers including breast, colon, prostate, uterus, liver, and pancreas. Additionally, studies have shown a potential reduction in the risk of heart disease. Given all of these potential health benefits, it is therefore of no surprise that bariatric surgery has also been shown to improve quality of life.
It is no great secret that all surgical procedures carry some degree of risk and consequences. Bariatric surgery involves the performance of complicated surgical procedures in complicated patients. It is therefore not surprising that the potential for catastrophic complications and even death exists with all of the operative procedures. However, as stated above, the introduction of advanced laparoscopic techniques, improved perioperative care, and the participation in the “Centers of Excellence” programs have resulted in dramatic reductions in complications.
Overall complication rates are relatively low. For the band, band erosion occurs in 1-2%, band prolapse in 1-2%, and port problems in approximately 4%. Sleeve complications include a 1-2% risk of leak and a 2% risk of stricture. The overall complication rate for the gastric bypass is 10-15%. This includes a leak rate of 1-2%, anastomotic stricture rate of 1-2%, a bleeding rate of 3-4%, and a 1% risk of bowel obstructions.
For all procedures, the risk of blood clots is less than 1%. Vitamin and mineral deficiencies are more common with the sleeve, gastric bypass, and the duodenal switch secondary to malabsorption but can even be seen with the band due to dietary derangements. It is therefore imperative that patients who undergo any type of weight reduction surgery have regular follow up with a physician who can monitor for these deficiencies.
Despite the low complication rates and good results, currently less than 1% of potential patients undergo bariatric surgery. While there are several factors that contribute to this phenomenon, one of the most significant is that many patients are just not interested in the current operative choices. They are concerned about the risks, do not want to have their gastrointestinal tracts permanently altered, and/or do not want to be exposed to the potential long term issues (i.e. vitamin supplementation, dietary restrictions). Many have expressed the desire for simpler, less risky options. With so few patients undergoing surgery, there is a tremendous opportunity for innovative new therapies to be introduced. Several are currently under investigation involving either endoscopic-based approaches or laparoscopically implanting electric pulse generator devices onto the gastrointestinal tract.
Scott A. Shikora, MD, The Center for Metabolic Health and Bariatric Surgery, Department of Surgery, Brigham and Women’s Hospital, Boston, MA – Updated January 2015.
Scott A. Shikora, MD and Rebecca Shore, MD, Tufts-New England Medical Center, Boston, MA – Published January 2006.