Gastrointestinal Surgery For Severe Obesity
There are two main types of bariatric surgery:
1. Restrictive Procedures
Gastrointestinal surgery promotes weight loss by closing off parts of the stomach to make it smaller, thus restricting food intake. Operations that only reduce stomach size are known as restrictive operations because they restrict the amount of food the stomach can hold. These operations only reduce the volume of food the stomach is capable of holding. They do not alter the anatomy of the digestive system. The bariatric surgeon partially closes part of the stomach with an adjustable band or line of special stomach-staples, thus creating a small pouch. Food leaves the pouch via an opening into the lower stomach, which is deliberately made small to delay emptying. There are four types of restrictive bariatric procedures: gastric stapling, vertical banded gastroplasty (VGB), gastric banding, and adjustable gastric banding (AGB). The most popular is adjustable gastric banding, also called Lap Band.
2. Malabsorptive Procedures
Originally, the main malabsorptive operation was the jejunoileal bypass. This procedure is no longer performed because of the high incidence of health complications. Nowadays, gastrointestinal bypass operations involve stomach restriction as well as a partial bypass of the small intestine. These stomach bypass procedures create a direct connection from the stomach to the lower segment of the small intestine, bypassing portions of the digestive tract that absorb calories and nutrients. Typically, the bariatric surgeon bypasses the lower stomach, duodenum, and most of the jejunum. The small intestine is the region of highest caloric and nutrient absorption. Malabsorptive procedures include: Roux-en-Y (RGB), and Biliopancreatic diversion (BPD), with or without Duodenal Switch. At present, the Roux-en-Y (RGB) gastric bypass is the most popular procedure, with the highest long-term success rate and low rates of mortality, complications and failures. A Roux-en-Y operation may bypass a moderate length of intestine (Proximal RGB) or a large length (Distal RGB). Obesity surgeons can now perform RGB using a laparoscope.
Comparison of Restrictive and Malabsorptive Procedures
The main advantage of Lap Band and other restrictive procedures, is that they are reversible and involve no permanent rearrangement of the digestive system. One reason why only lap band operations are performed on severely obese adolescents. Also, the lap band itself may be adjusted to suit patients’ food intake and physiology. Patients tend to lose less weight after gastrointestinal stapling or banding, than gastric bypass patients. It is easier to cheat, and does not compel the patient to change their post-op eating habits in the same way as does gastric bypass. About 1 in 3 of those who undergo vertical banded gastroplasty achieve normal weight, and about 8 out of 10 lose some weight. Studies indicate that 10 years after surgery, only 1 in 10 of patients maintain a weight loss of half their initial excess weight. After gastric banding, patients average a weekly weight reduction of 1-2 pounds, while more obese patients lose more. This adds up to about 50 to 100 pounds in the first 12 months for most lap band patients. According to Australian research into weight loss after bariatric surgery, AGB patients lose less weight than RGB bypass patients to begin with, but similar amounts after 4, 5 and 6 years. Even so, malabsorptive procedures typically lead to greater weight loss than restrictive procedures, and, thus they are more successful in improving or curing the health problems and co-morbidities linked with with obesity. Patients who undergo Roux-en-Y stomach bypass typically lose about 66 percent of their excess weight (about 100 pounds) within the first 24 months after their obesity surgery, and most patients are able to maintain this weight loss in the long term.
Health Complications Of Gastrointestinal Bariatric Operations
Recent studies of obesity surgery (2006) show that 39.6 percent of patients experienced complications within 180 days of surgery. The most common complications are:
- A combination of gastrointestinal symptoms including vomiting, diarrhea, dysphagia, and reflux (20 percent).
- Anastomotic leaking, commonly from the ‘stitched together’ connections between the stomach and the intestine (12 percent).
- Abdominal hernia (7 percent).
- Infections (6 percent).
In addition, approximately 7 percent of patients required hospitalization within 6 months to treat specific health complications of their bariatric procedure. Out of 104,702 adults who underwent obesity surgery in 2003, there were 212 hospital deaths. This is a death rate of 0.2 per cent.
What Is Laparoscopic Surgery?
Gastrointestinal surgery to reduce obesity can now be performed laparoscopically, using “keyhole” surgical techniques. The bariatric surgeon uses fiber optic lenses and small instruments connected to a video camera, a procedure which entails smaller incisions, reduced pain, less scarring, and a faster post-op recovery time. In 2000, a gastric band called the MIDband ® was used in France. This was manufactured specifically for laparoscopic insertion. Other bands have followed. Laparoscope-assisted surgery typically reduces the risk of incisional hernias (caused when abdominal contents bulge through the weakness in the abdominal wall created by the scar), although it tends to take longer than open surgery. It may also result in more internal complications, such as anastomotic leakages from connections between sections of intestine and between the stomach and intestine. Bariatric experts expect these complication rates to reduce as surgeons become more experienced at laparoscopy. At present, super-obesity is a contra-indication for laparoscopic gastric surgery.
Gastrointestinal Surgery For Super-Obese Patients
One procedure which may be performed laparoscopically on extremely obese patients (BMI > 60) is a two-step Sleeve Gastrectomy. During the first stage of this bariatric procedure, roughly two thirds of the stomach is surgically removed. The remaining section is stapled into the shape of a sleeve or tube. The second stage, usually performed 8 to 12 months after the first, involves a gastric bypass.
What is Open Surgery?
Bariatric surgeons perform traditional open surgery through a large incision in the abdomen. The main advantage of open surgery is that it allows the surgeon to place his hands directly into the abdomen. This ease of access is important if the operation is expected to be technically difficult (due to very severe patient obesity, or significant scarring from prior surgery). Open surgery operations are also faster. The main disadvantage of open surgery is that it needs a large incision. Such operations are therefore more painful, involve greater scarring and require more recovery time than those performed laparoscopically.
What is Revisional Bariatric Surgery?
Revisional obesity surgery corrects a previous bariatric operation, or updates an outmoded procedure. For example, many patients who had a jejunoileal bypass – no longer performed because of severe health complications – have undergone revisional surgery (eg. Roux-en-Y bypass) to reverse health problems such as nutritional deficiencies and liver and kidney abnormalities. Also, patients who had vertical banded gastroplasty (stomach stapling) have undergone revisional surgery during which their VBG procedure was converted to a gastric bypass or a BPD-DS (duodenal switch). Note however that revisional procedures are major operations, and carry risks that are greater than those for a primary procedure.
Gastrointestinal Surgery – Good Weight Loss Results
Although bariatric surgery has a direct impact on obesity, patients are advised that long term success depends upon lifetime changes in eating and exercise habits.