Gastric bypass, also called Roux-en-Y (roo-en-wy) gastric bypass, is a type of weight-loss surgery that involves creating a small pouch from the stomach and connecting the newly created pouch directly to the small intestine. After gastric bypass, swallowed food will go into this small pouch of stomach and then directly into the small intestine, there by bypassing most of the stomach and the first section of the small intestine.
Gastric bypass is one of the most commonly performed types of bariatric surgery. Gastric bypass is done when diet and exercise haven’t worked or when you have serious health problems because of your weight.
Gastric bypass is done to help you lose excess weight and reduce your risk of potentially life-threatening weight-related health problems, including:
- Gastroesophageal reflux disease
- Heart disease
- High blood pressure
- High cholesterol
- Obstructive sleep apnea
- Type 2 diabetes
- Stroke
- Cancer
- Infertility
Gastric bypass is typically done only after you’ve tried to lose weight by improving your diet and exercise habits.
The Consensus Panel of the National Institutes of Health (NIH) recommended the following criteria for consideration of bariatric surgery, including gastric bypass procedures:
- people who have a BMI of 40 or highe
- people with a BMI of 35 or higher with one or more related comorbid conditions such as type 2 diabetes,high blood pressure or severe sleep apnea.
In some cases, for certain types of weight-loss surgery if BMI is 30 to 34 and there are serious weight-related health problems
Surgical techniques
Laparoscopic surgery is performed using several small incisions, or ports: one to insert a surgical telescope connected to a video camera, and others to permit access of specialized operating instruments. The surgeon views the operation on a video screen. With experience, a skilled laparoscopic surgeon can perform most procedures as expeditiously as with an open incision—with the option of using an incision should the need arise. The Roux-en-Y laparoscopic gastric bypass, first performed in 1993, is regarded as one of the most difficult procedures to perform by limited access techniques. However the use of this method has greatly popularized the operation due to associated benefits such as a shortened hospital stay, reduced discomfort, shorter recovery time, less scarring, and minimal risk of incisional hernia.
Complications of gastric bypass
- Anastomotic leakage
Leakage can occur in about 2% of Roux-en-Y gastric bypass and less than 1% in mini gastric bypass. Leaks usually occur at the stomach-intestine connection (gastro-jejunostomy).
- Anastomotic stricture
As the anastomosis heals, it forms scar tissue, which naturally tends to shrink (“contract”) over time, making the opening smaller. This is called a “stricture”
- Anastomotic ulcer
Ulceration of the anastomosis occurs in 1–16% of patients.
- Dumping syndrome
Normally, the pyloric valve at the lower end of the stomach regulates the release of food into the bowel. When the gastric bypass patient eats a sugary food, the sugar passes rapidly into the intestine, where it gives rise to a physiological reaction called dumping syndrome. An affected person may feel their heart beating rapidly and forcefully, break into a cold sweat, get a feeling of butterflies in the stomach, and may have an anxiety attack. The person usually has to lie down and could be very uncomfortable for 30–45 minutes.
Nutritional deficiencies
Nutritional deficiencies are common after gastric bypass surgery, and are often not recognized. They include:
- Secondary hyperparathyroidism due to inadequate absorption of calcium may occur for GBP patients.. Most patients can achieve adequate calcium absorption by supplementation with vitamin D and calcium citrate
- Iron frequently is seriously deficient, particularly in menstruating females, and must be supplemented. signs of iron deficiency include: brittle nails, an inflamed tongue, constipation, depression, headaches, fatigue, and mouth lesions.
- zinc deficiency may also occur
- Deficiency of vitamin B1
- Vitamin B12 deficiency is quite common after gastric bypass surgery with reported rates of 30% in some clinical trials.
- Protein malnutrition is a real risk. Many patients require protein supplementation during the early phases of rapid weight loss to prevent excessive loss of muscle mass. Hair loss is also a risk of protein malnutrition.
Nutritional effects
After surgery, patients feel fullness after ingesting only a small volume of food, followed soon thereafter by a sense of satiety and loss of appetite. Total food intake is markedly reduced. Due to the reduced size of the newly created stomach pouch, and reduced food intake, adequate nutrition demands that the patient follow the surgeon’s instructions for food consumption, including the number of meals to be taken daily, adequate protein intake, and the use of vitamin and mineral supplements. Calcium supplements, iron supplements, protein supplements, multi-vitamins (sometimes pre-natal vitamins are best), and vitamin B12 (cyanocobalamin) supplements are all very important to the post-operative bypass patient.
Total food intake and absorbance rate of food will rapidly decline after gastric bypass surgery, and the number of acid-producing cells lining the stomach increases. Doctors often prescribe acid-lowering medications to counteract the high acidity levels.
Protein nutrition
With reduced ability to eat a large volume of food, gastric bypass patients must focus on eating their protein requirements first, and with each meal. In some cases, surgeons may recommend use of a liquid protein supplement. Powdered protein supplements added to smoothies or any food can be an important part of the post-op diet.
Calorie nutrition
The profound weight loss which occurs after bariatric surgery is due to taking in much less energy (calories) than the body needs to use every day. Fat tissue must be burned to offset the deficit, and weight loss results. Eventually, as the body becomes smaller, its energy requirements are decreased, while the patient simultaneously finds it possible to eat somewhat more food. When the energy consumed is equal to the calories eaten, weight loss will stop. Proximal GBP typically results in loss of 60–80% of excess body weight, and very rarely leads to excessive weight loss. The risk of excessive weight loss is slightly greater with distal GBP.
Vitamins
Supplements should be taken to complete minimum daily requirements of all vitamins and minerals. Absorption of most vitamins is not seriously affected after proximal GBP, although vitamin B12 may not be well-absorbed in some persons.After a distal GBP, fat-soluble vitamins A, D, and E may not be well-absorbed, particularly if fat intake is large. Water-dispersed forms of these vitamins may be indicated on specific physician recommendation.
Alcohol metabolism
Post-operative gastric bypass patients develop a lowered tolerance for alcoholic beverages because their altered digestive tract absorbs alcohol at a faster rate than people who have not undergone the surgery.
Results and health benefits of gastric bypass
Weight loss of 65–80% of excess body weight is typical of most large series of gastric bypass operations reported. The medically more significant effects include a dramatic reduction in comorbid conditions:
- Hyperlipidemia is corrected in over 70% of patients.
- Essential hypertension is relieved in over 70% of patients, and medication requirements are usually reduced in the remainder.
- Obstructive sleep apnea improves markedly with weight loss and bariatric surgery may be curative for sleep apnea. Snoring also reduces in most patients.
- Type 2 diabetes is reversed in up to 90% of patients usually leading to a normal blood-sugar level without medication, sometimes within days of surgery.
- Gastroesophageal reflux disease is relieved in almost all patients.
- Venous thromboembolic disease signs such as leg swelling are typically alleviated.
- Lower-back pain and joint pain are typically relieved or improved in nearly all patients.
Concurrently, most patients are able to enjoy greater participation in family and social activities
After the procedure
Immediately after gastric bypass surgery, you may have liquids but no solid food as your stomach and intestines begin to heal. You’ll then follow a special diet plan that changes slowly from liquids to pureed foods. After that, you can eat soft foods, then move on to firmer foods as your body is able to tolerate them.
Your doctor will recommend you take vitamin and mineral supplements after surgery, including a multivitamin with iron, calcium and vitamin B-12.
In the first three to six months after gastric bypass you may experience changes as your body reacts to the rapid weight loss , including:
- Body aches
- Feeling tired, as if you have the flu
- Feeling cold
- Dry skin
- Hair thinning and hair loss
- Mood changes
Results
Gastric bypass can provide long-term weight loss. The amount of weight you lose depends on your type of surgery and your change in lifestyle habits. It may be possible to lose about 70%, or even more, of your excess weight within two years.
In addition to weight loss, gastric bypass may improve or resolve conditions often related to being overweight, including:
- Gastroesophageal reflux disease
- Heart disease
- High blood pressure
- High cholesterol
- Obstructive sleep apnea
- Type 2 diabetes
- Stroke
- Infertility
Gastric bypass can also improve your ability to perform routine daily activities, which could help improve your quality of life.
