Bariatric Surgery
Causes of Obesity
Obesity is a complex and chronic disease with many causes. It is not simply a result of overeating. Research has shown that genetics can play a significant role in determining a person's body weight, particularly for morbidly obese people, and that diet and exercise may have a limited ability to provide effective, long-term relief for obese people.
In addition to genetics, factors such as the environment, metabolism, eating disorders and certain medical conditions may contribute to obesity.
Genetics
Research has shown that a person's genes play an important role in their tendency to gain weight. Just as some genes determine eye color or height, others affect appetite, ability to feel full or satisfied, metabolism, fat-storing ability and even natural activity levels.
Environment
Environmental and genetic factors are closely intertwined. If you have a genetic predisposition towards obesity, the modern American lifestyle and environment may make controlling weight more difficult.
Fast food, long days sitting at a desk and suburban neighborhoods that require cars exacerbate hereditary factors such as metabolism and efficient fat storage. For those suffering from morbid obesity, anything less than a total change in environment usually results in failure to reach and maintain a healthy body weight.
Metabolism
We used to think that a person could lose weight if they burned more calories than they consumed. Now we know that for some people, it's not that simple.
Obesity researchers now refer to a theory called the "set point," a sort of thermostat in the brain that makes people resistant to either weight gain or loss. If you try to override the set point by drastically cutting your calorie intake, your brain responds by lowering metabolism and slowing activity. You then gain back any weight you lost.
Eating Disorders
Many obese and morbidly obese people suffer from eating disorders. In these cases, behavior and diet modification therapy are recommended to help treat the eating disorder before weight loss surgery is considered.
There also are certain medical conditions, such as hypothyroidism, that can cause weight gain and may be treated with medication.
See information on the Weight Management Program at UCSF Medical Center.
Evaluation
There are several medically accepted criteria for defining morbid obesity. You might be considered morbidly obese if you meet any of the following critiera:
You may qualify for bariatric surgery, though technically not be morbidly obese, if you have a BMI of over 35 and suffer from conditions such as high blood pressure or diabetes, related to being severely overweight.
Obesity Health Risks
If you are obese or morbidly obese, you are at risk for developing a number of serious health problems. The most common conditions include:
Depression -- Depression is very common after repeated failure with dieting and disapproval from family, friends and the public.
Diabetes -- Obese individuals develop a resistance to insulin, which regulates blood sugar levels. Over time, high blood sugar can cause type 2 diabetes that can lead to serious damage to the body.
Gastroesophageal Reflux or Heartburn -- When acid escapes from the stomach into the esophagus through a weak or overloaded valve, gastroesophageal reflux can occur, causing "heartburn" and acid indigestion. Gastroesophageal reflux disease can lead to Barrett's esophagus, a pre-cancerous change in the lining of the esophagus and a cause of esophageal cancer.
High Blood Pressure and Heart Disease -- Excess body weight strains the heart. This may lead to high blood pressure, which can cause strokes as well as heart and kidney damage.
Incontinence -- In obese people, a large, heavy abdomen may cause the valve on the urinary bladder to weaken, leading to urinary stress incontinence or the leakage of urine with coughing, sneezing or laughing.
Infertility -- Obese women may experience infertility -- an inability or diminished ability to become pregnant.
Osteoarthritis -- The weight placed on joints, particularly knees and hips, results in rapid wear and tear of joints as well as pain caused by inflammation, called osteoarthritis. Excess weight puts a strain on bones and muscles of the back, which can cause disk problems, pain and decreased mobility.
Sleep Apnea and Respiratory Problems -- Fat deposits in the tongue and neck can cause intermittent obstruction of your air passage, called sleep apnea. Because the obstruction is more severe when sleeping on your back, you may wake frequently to reposition yourself. Loss of sleep often causes drowsiness and headaches.
Evaluation Process
To be considered for bariatric surgery, you must weigh less than 450 pounds because our hospital X-ray equipment can't accommodate patients who weigh more. A nutritionist is available to help you lose weight to meet this requirement, if necessary.
You also must complete a medical and psychological evaluation and undergo an initial consultation with a surgeon. To streamline this process, you can coordinate most of your medical evaluations with your primary care doctor. A psychological evaluation with a certified mental health professional as well documentation of participation in a supervised weight-loss program also are required.
This information is sent to UCSF where it is reviewed by our team of surgeons, gastroenterologists and nurses. You will be asked to meet with a surgeon to discuss the procedure. At this time, you can ask any questions you may have.
When your pre-operative evaluation and tests have been successfully completed, we will schedule a follow-up appointment and arrange a surgery date.
The evaluation process, which takes about six to eight months, consists of the following steps:
Treatment
There are countless weight-loss strategies available but many are ineffective and short-term, particularly for those who are morbidly obese. Among the morbidly obese, less than 5 percent succeed in losing a significant amount of weight and maintaining the weight loss by participating in non-surgical programs — usually a combination of dieting, behavior modification therapy and exercise.
There are cases, however, where people do lose weight without surgery, particularly when they work with a certified health care professional to develop an effective and safe weight-loss program. Most health insurance companies don't cover weight loss surgery unless you first made a serious effort to lose weight using non-surgical approaches.
Many people participate in a combination of the following therapies.
Dietary Modification
Many of us have tried a variety of these diets and have been caught in a cycle of weight gain and loss — "yo-yo" dieting — that can cause serious health risks by stressing the heart, kidneys and other organs. Ninety percent of people participating in all diet programs regain the weight they've lost within two years. However, for people who have weight-loss surgery, dieting is an instrumental part of maintaining weight loss after surgery.
If you decide to go on a diet, we recommend that you work with a certified health professional who can customize a diet to meet your needs. A diet should greatly restrict your calorie intake, but also maintain your nutrition. Calorie-restrictive diets fall into two basic categories.
Low calorie diets (LCDs) are individually planned so that the patient takes in 500 to 1,000 fewer calories a day than he or she burns.
Very low calorie diets (VLCDs) typically limit caloric intake to 400 to 800 a day and feature high-protein, low-fat liquids.
See information on the Weight Management Program at UCSF Medical Center.
Behavior Modification
Behavior modification therapy is designed to change your eating and exercise habits to promote weight loss. Examples include:
Although some people experience success with behavior modification, most patients achieve only short-term weight loss for the first year. If you plan on having weight-loss surgery, behavior therapy and dieting will be instrumental in helping you maintain your weight loss after surgery.
Surgery is a tool to get your body to start losing weight. Diet and behavior modification will determine your ultimate success.
Exercise
Exercise greatly increases your chance of long-term weight loss. It is a key component for any long-term weight management program, particularly weight-loss surgery.
Research shows that when you reduce the number of calories you consume, your body reacts by slowing your metabolism to burn fewer calories, rather than promote weight loss. Daily physical activity can help speed up your metabolism, effectively reducing the "set point" -- a sort of thermostat in the brain that makes you resistant to either weight gain or loss -- to a lower natural weight.
Starting an exercise program can be especially intimidating if you're morbidly obese. Your health condition may make any level of physical exertion extremely difficult. But you can learn strategies to help you start a realistic exercise routine. The following strategies are designed to help you start exercising and can be incorporated into your daily routine.
Medications
There are a variety of over-the-counter and prescription weight loss drugs available. Some people find that they help curb their appetites. Studies show that patients on drug therapy lose around 10 percent of their excess weight, and that the weight loss plateaus after six to eight months. As patients stop taking the medication, weight gain usually occurs.
Weight loss drugs, approved by the US Food and Drug Administration (FDA) for treating obesity, include:
Orlistat (Xenical) -- Orlistat is the most recently approved by the federal Food and Drug Administration. It works by blocking about 30 percent of dietary fat from being absorbed.
Phentermine -- Phentermine, an appetite suppressant, has been available for many years. It is half of the "fen-phen" combination that remains available for use. The use of phentermine alone has not been associated with the adverse health effects of the fenfluramine-phentermine combination.
Sibutramine (Meridia) -- Sibutramine is an appetite suppressant approved for long-term use.
Medications are an important part of the morbid obesity treatment process but weight-loss drugs can have serious side effects. We recommend that you visit a certified health care professional who can prescribe appropriate medications. Before insurance companies will reimburse you for weight-loss surgery, you must follow a well-documented treatment plan that typically includes medications.
Surgery
After trying a variety of weight-loss approaches, many people suffering from morbid obesity are unsuccessful in losing and keeping off the weight and opt for weight loss surgery. In 2000, about 40,000 weight-loss surgical procedures were performed in the United States.
Bariatric surgery, which involves sealing off most of the stomach to reduce the amount of calories you can consume, currently is the most effective means by which morbidly obese people can lose weight and maintain that weight loss.
To be considered for weight-loss surgery, you must meet at least one of the following qualifications:
Be more than 100 pounds over your ideal, recommended body weight.
Have a body mass index (BMI) of 40 or higher (20 to 25 is considered a normal). BMI is a number based on both your height and weight. Surgery may be considered with a BMI as low as 35 if your doctor determines that there's a medical need for weight reduction and surgery appears to be the only way to accomplish the targeted weight loss.
To qualify for surgery, you must complete a medical and psychological pre-evaluation process. You must show that you are committed to adhering to long-term, follow-up care after surgery. Most surgeons require that you demonstrate serious motivation and a clear understanding of the extensive dietary, exercise and medical guidelines that must be followed for the remainder of your life.
The UCSF Bariatric Surgery Center has performed surgical weight loss procedures since 1996. Various procedures involve different risks and advantages. During your initial consultation, your surgeon will discuss in detail the different options available to you, along with their associated risks and advantages.
The most common bariatric surgeries are "restrictive" procedures that reduce the size of the stomach and limit the calories you can consume. Another type of procedure -- called a malabsorptive procedure -- alters your digestion, causing food to be poorly digested and incompletely absorbed so that it is eliminated in the stool.
Gastric Restrictive Procedures
Roux-en-Y Gastric Bypass
Roux-en-Y gastric bypass is the current "gold standard" procedure for weight-loss surgery, according to the American Society for Bariatric Surgery and the National Institutes of Health. One of the most frequently performed weight-loss procedures in the United States, it involves stapling the stomach to create a small -- 15 to 20 cubic centimeter -- stomach pouch. The remainder of the stomach is not removed, but is stapled shut and divided from the stomach pouch.
The outlet from this newly formed pouch empties directly into the lower portion of the small intestine, called the jejunum, thus bypassing calorie absorption. This is done by dividing the small intestine just beyond the duodenum to connect it with the newly formed stomach pouch. The other end is connected to the side of the Roux limb of the intestine creating a "Y" shape that gives the technique its name. The length of either segment of the intestine can be increased to produce some degree of malabsorption.
Advantages
Average weight loss after the Roux-en-Y procedure is generally higher if you rigorously follow instructions than with other restrictive procedures.
A year after surgery, weight loss averages 77 percent of excess body weight.
Studies show that after 10 to 14 years, 50 percent to 60 percent of excess body weight loss is maintained by some patients.
A study of 500 patients, conducted in 2000, showed that 96 percent of certain health conditions -- including back pain, sleep apnea, high blood pressure, diabetes and depression -- were improved or resolved.
Disadvantages
Because the duodenum is bypassed, poor absorption of iron and calcium can result in the lowering of total body iron, which may result in iron deficiency anemia. This is a particular concern for patients who experience chronic blood loss during excessive menstrual flow or bleeding hemorrhoids. Women, already at risk for osteoporosis that can occur after menopause, should be aware of the potential for heightened bone calcium loss.
Bypassing the duodenum has caused metabolic bone disease in some patients, resulting in bone pain, loss of height, humped back and fractures of the ribs and hip. All of the deficiencies mentioned, however, can be managed through proper diet and vitamin supplements.
Chronic anemia due to Vitamin B12 deficiency may occur. This problem usually can be managed with Vitamin B12 pills or injections.
A condition known as "dumping syndrome" can occur as the result of rapid emptying of stomach contents into the small intestine. This is sometimes triggered when too much sugar or large amounts of food are consumed. While generally not considered a serious health risk, the results can be unpleasant, including nausea, weakness, sweating, faintness and, on occasion, diarrhea after eating. Some patients are unable to eat any form of sweets after surgery.
In some cases, the procedure's effectiveness may lessen if the stomach pouch is stretched or if it is initially left larger than 15 to 30 cubic centimeters.
The bypassed portion of the stomach, duodenum and segments of the small intestine cannot be easily visualized using X-ray or endoscopy if problems such as ulcers, bleeding or malignancy occur.
Laparoscopic Adjustable Gastric Band (Lap-band)
In this procedure, an adjustable silicone band is placed around the upper part of the stomach to create a stomach pouch that can hold only small amounts of food. The lower, larger part of the stomach is located below the band. The outlet from the pouch is restricted by the band, which slows the emptying of the food and allows one to feel full sooner. Adjustment of the band is performed in the doctor's office by injecting fluid into a small "port," a device implanted beneath the abdominal skin.
Advantages
Application of the band is less invasive and doesn't involve stapling or cutting the stomach.
The band is adjustable, allowing your doctor to control the size of the pouch outlet.
If the band needs to be removed for any reason, the stomach usually returns to its original form.
Disadvantages
The procedure is relatively new in the United States and it's effectiveness still is being studied. However, it has been used extensively and with good results in Europe and Australia.
Insurance companies vary widely in the coverage they provide for this procedure.
Vertical banded gastroplasty (VBG) is a restrictive procedure performed less frequently today. The upper stomach near the esophagus is stapled vertically for about 2-1/2 inches, or 6 centimenters, to create a smaller stomach pouch. The outlet from the pouch is restricted by a band or ring that slows the emptying of the food. As a result, a patient will experience a feeling of fullness sooner.
Advantages
The main advantage of this restrictive procedure is that a reduced amount of well-chewed food enters and passes through the digestive tract in the normal way. the body is able to fully absorb nutrients, vitamins and calories. Studies show that after 10 years, patients can maintain 50 percent of their targeted excess weight loss.
Disadvantages
Following surgery, staple-line disruption in the stomach can result in leakage or serious infection, requiring hospitalization with antibiotic treatment and or additional operations.
Staple-line disruption also may lead to weight gain in the long-term. For this reason, some surgeons divide the staple-line wall of the pouch from the rest of the stomach to reduce the risk of staple-line disruption.
The band or ring applied to the stomach pouch may lead to obstruction or perforation, requiring surgical intervention.
Typically, these procedures create a sense of fullness, but often not the satisfying feeling of having had "enough" to eat.
Because restrictive procedures rely on a small pouch to reduce food intake, there is a risk of the pouch stretching or the restricting band or ring breaking or migrating, allowing patients to eat too much.
About 40 percent of patients undergoing these procedures have lost less than half of their excess body weight.
All weight-loss surgeries may require readmission to a hospital for fluid replacement or nutritional support if a patient experiences excessive vomiting and cannot maintain adequate amounts of food.
Malabsorptive Procedures
Like gastric restrictive procedures, malabsorptive procedures reduce the size of the stomach, although the stomach pouch is larger. The goal is to restrict the food consumed and alter the normal digestive process. The anatomy of the small intestine is altered so that food is delayed in mixing with bile and pancreatic juices, which aid in the absorption of nutrients. The result is an early sense of fullness, combined with a sense of satisfaction that reduces the desire to eat.
Sleeve Gastrectomy
This procedure involves removing the outer margin of the stomach to restrict food intake, leaving a sleeve of stomach with the pylorus, the muscle that controls emptying of food from the stomach into the intestine. When a sleeve gastrectomy is performed alone, this procedure functions as a purely restrictive procedure.
Biliopancreatic Diversion with Duodenal Switch
Currently, this two-step procedure is not performed at UCSF Medical Center.
This involves performing a sleeve gastrectomy as the first step of the procedure, sometimes performed separately to allow initial weight loss before completing the procedure. After the sleeve gastrectomy is performed, the duodenum, which is the first portion of the small intestine, is divided so pancreatic and bile drainage is bypassed.
The near-end of the "alimentary limb" is then attached to the beginning of the duodenum, just past the pyloris, while the bile and pancreatic juices move through the long "biliopancreatic limb." A "common limb" is created by connecting the "alimentary" and "biliopancreatic" limbs a short distance from the end of the small bowel. Food mixes with the digestive juices in this portion of the intestine and is absorbed.
The length of the common limb may vary to regulate the absorption of carbohydrates, protein, fat and other nutrients.
Extended (Distal) Roux-en-Y Gastric Bypass (RYGBP-E)
RYGBP-E is an alternative to achieve malabsorption by creating a stapled or divided small gastric pouch, leaving the remainder of stomach in place. A long limb of the small intestine is attached to the stomach to divert the bile and pancreatic juices. This procedure carries with it fewer operative risks by avoiding removal of the lower three-quarters of the stomach. Gastric pouch size and the length of the bypassed intestine determine the risks for ulcers, malnutrition and other side effects.
Advantages
Patients can eat larger meals than with a purely restrictive or standard Roux-en-Y gastric bypass procedure.
These procedures can produce the greatest excess weight loss because they provide the highest levels of malabsorption.
In one study of 125 patients, the loss of excess weight averaged 74 percent the first year, 78 percent after two years, 81 percent after three years, 84 percent after four years and 91 percent after five years.
Long-term maintenance of weight loss can be successful with a straightforward dietary, supplement, exercise and behavioral regimen.
Disadvantages
Weight-loss surgeries may require hospitalization for fluid replacement or nutritional support if a patient experiences excessive vomiting and cannot maintain adequate amounts of food.
For all malabsorption procedures, there is a period of intestinal adaptation when bowel movements can be very liquid and frequent. This condition may lessen over time, but may be a permanent lifelong occurrence.
Abdominal bloating and malodorous stool or gas may occur.
Close monitoring for protein malnutrition, anemia and bone disease is recommended. Lifelong vitamin supplements are required. If patients don't follow eating and vitamin instructions, at least 25 percent of patients will develop problems that require treatment.
Changes to the intestinal structure can result in increased risk of gallstone formation and the need to remove the gallbladder.
Re-routing of bile and pancreatic and other digestive juices beyond the stomach can cause intestinal irritation and ulcers.
Laparoscopic or Minimally Invasive Surgery
Laparoscopic, or minimally invasive, procedures have been used for weight loss surgery for several years. During a laparoscopic operation, a small video camera is inserted into the abdomen. The surgeon views the procedure on a separate video monitor, allowing for better visualization and access. The camera and surgical instruments are inserted through small incisions made in the abdominal wall. Not all surgeons offer laparoscopic weight loss surgery because they aren't properly trained.
The American Society for Bariatric Surgery recommends that laparoscopic weight-loss surgery be performed only by surgeons experienced in both laparoscopic and open bariatric procedures. At the UCSF Bariatric Surgery Center, our experts are trained in the advanced techniques required to perform laparoscopic procedures.
Laparoscopic surgery is considered less invasive because it replaces the need for one long incision to open the abdomen. A recent study showed that patients who underwent laparoscopic weight-loss surgery experienced less pain after surgery, resulting in easier breathing and lung function and higher overall oxygen levels.
Other benefits of laparoscopy are fewer wound complications, such as infection or hernia, and patients returning more quickly to their normal levels of activity.
Not all patients, however, are candidates for this approach.
Follow-Up Care
Follow-up care, including support groups, dietitian services and other forms of continuing education, is offered. For more information, see "Dietary Guidelines" and "Life After Surgery."
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