BARIATRIC SURGERY – A SERIOUS APPROACH TO A SERIOUS PROBLEM
Bariatric surgery is a major surgery. Surgery should be viewed first and foremost as a method for alleviating debilitating disease. In most cases, the minimum qualification for consideration as a candidate for the procedure is those with a Body Mass Index (BMI) of 40 or greater. The procedure will also be considered for someone with a BMI of 35 or greater with co-morbid health conditions (like diabetes type 2, hypertension, hyperlipidemia, osteo-arthritis or sleep apnea).
In many cases, patients are required to show proof that their attempts at dietary weight loss have been ineffective before surgery will be approved. More important, however, is the commitment on the part of the patient to demonstrate serious motivation and a clear understanding of the extensive dietary, exercise, and medical guidelines that must be followed for the remainder of their lives after having bariatric surgery.
HOW EFFECTIVE IS BARIATRIC SURGERY?
The actual weight a patient will lose after the procedure is dependent on several factors. These include:
- Patient’s age
- Weight before surgery
- Overall condition of patient’s health
- Surgical procedure
- Ability to exercise
- Commitment to maintaining dietary guidelines and other follow-up care
- Motivation of patient and cooperation of family, friends and associates.
Patients with higher initial BMIs tend to lose more total weight. Patients with lower BMIs will lose a greater percentage of their excess weight and will more likely come closer to their ideal body weight.
Patients with type 2 diabetes tend to show less overall excess weight loss than patients without type 2 diabetes. Many patients with type 2 diabetes, while showing less overall excess weight loss, have demonstrated excellent resolution of their diabetic condition, to the point of having little or no need for continuing medication.
Bariatric surgery also has been found to be effective in improving and controlling many obesity-related health conditions. A comprehensive clinical review of bariatric surgery data (from a 2004 meta-analysis of more than 22 000 patients) showed that patients who underwent a bariatric surgical procedure experienced complete resolution or improvement of their co-morbid conditions including diabetes, hyperlipidemia, hypertension and obstructive sleep apnea.
UNDERSTANDING THE GASTROINTESTINAL TRACT
To better understand how bariatric surgery works, it is important to understand how your gastrointestinal tract functions. As the food you consume moves through the tract, various digestive juices and enzymes are introduced at specific stages that allow absorption of nutrients.
Food material that is not absorbed is then prepared for elimination. A simplified description of the gastrointestinal tract appears below.
1. The esophagus is a long, muscular tube that moves food from the mouth to the stomach.
2. The abdomen contains all of the digestive organs.
3. A valve at the entrance to the stomach from the esophagus allows the food to enter, while keeping the acid-laden food from “refluxing” back into the esophagus, causing damage and pain.
4. The stomach, situated at the top of the abdomen, normally holds just over 1 500 mℓ of food from a single meal. Here, the food is mixed with an acid that is produced to assist in digestion. In the stomach, acid and other digestive juices are added to the ingested food to facilitate breakdown of complex proteins, fats, and carbohydrates into small, more absorbable units,
5. The pylorus is a small, round muscle located at the outlet of the stomach and the entrance to the small intestine. It closes the stomach outlet while food is being digested into a more easily absorbed form. When food is properly digested, the pylorus opens and allows the contents of the stomach into the first portion of the small intestine.
6. The small intestine is about 6m long and is where the majority of absorption of the nutrients from food takes place. The small intestine is made up of three sections: the duodenum, the jejunum and the ileum.
7. The duodenum is the first section of the small intestine and is where the food is mixed with bile produced by the liver and with other juices from the pancreas. This is where much of the iron and calcium is absorbed.
8. The jejunum is the middle part of the small intestine extending from the duodenum to the ileum; it is responsible for absorption of nutrients.
9. The last segment of the intestine, the ileum, is where the absorption of fat-soluble vitamins A, D, E and K and other nutrients occurs.
10. Another valve separates the small and large intestines to keep bacteria-laden colon contents from flowing back into the small intestine.
11. In the large intestine, protein and excess fluids are absorbed and a firm stool is formed.
HOW BARIATRIC SURGERY REDUCES EXCESS WEIGHT
Surgeons first began to recognize the potential for surgical treatment of morbid obesity while performing operations that required the removal of large segments of a patient’s stomach and intestine. After these surgeries, doctors noticed that many patients were unable to maintain their pre-surgical weight. With further study, surgeons were able to recommend similar modifications that could be safely used to produce weight loss in patients suffering from morbid obesity. Over the last decade, these procedures have been continually refined in order to improve results and minimize risks. Today’s bariatric surgeons have access to substantial clinical data to help them determine which procedure should be done and why.
Bariatric Surgeons describes 2 basic approaches that bariatric surgery takes to achieve change:
1. Restrictive procedures
2. Malabsorptive procedures
There are several procedures that combine the restrictive and malabsorptive mechanisms of bariatric surgery. The risk of complications and side effects generally increases with the alteration of the digestive process.
RESTRICTIVE PROCEDURES THAT DECREASE FOOD INTAKE
The theory is simple: When you feel full, you are more likely to have reduced feelings of hunger and will no longer feel deprived. The result is that you are likely to eat less. Restrictive bariatric surgery works by reducing the amount of food consumed at one time. It does not, however, interfere with the normal absorption (digestion) of food. In a restrictive procedure, the surgeon creates a small upper-stomach pouch. The pouch, with a capacity of approximately 15 to 30 mℓ connects to the rest of the stomach through an outlet known as a “stoma”. In a co-operative and compliant patient, the reduced stomach capacity, along with behavioral changes, can result in consistently lower caloric intake resulting in weight loss.
During recovery, patients must adhere to the strict, specific dietary guidelines and restrictions their surgeon prescribes. When the time comes to resume eating “regular” food, the patient must learn to adapt to a new way of eating. At each meal, patients are restricted to consuming approximately one-half to one full cup of food before feeling uncomfortably full.
Patients who see the best results from a restrictive procedure are those who learn to eat slowly, eat less, and avoid drinking to many fluids, particularly carbonated beverages. If the patient fails to follow these guidelines, he/she can stretch the stomach pouch and/or the stoma outlet and defeat the purpose of the surgery.
The effectiveness of a restrictive procedure is reduced by constant drinking high-calorie, high-fat liquids. Failure to achieve the expected level of weight loss is usually the result of a patient failing to comply with the recommended dietary and behavior modifications, such as increased exercise and regular support group attendance.
MALABSORPTIVE PROCEDURES THAT ALTER ABSORPTION
It can be said that some of the restrictive approaches discussed previously have not always achieved the excess weight loss surgeons and patients anticipated. For this reason, malabsorptive procedures were developed to work in conjunction with restrictive approaches. Malabsorptive procedures alter digestion, thus causing the food to be poorly digested and incompletely absorbed so that it is eliminated in the stool. In addition to restriction, these techniques involve a bypass of the small intestine, limiting the absorption of calories. On balance, malabsorptive or malabsorptive/restrictive procedures result in an overall increase in the loss of excess weight compared to purely restrictive procedures. The risk of complications generally increases with the lengthening of the small intestine bypass. You and your surgeon must determine the benefits and risks over your lifetime with the type of bariatric surgery you choose.
COMBINATION PROCEDURES DECREASE FOOD INTAKE AND ALTER ABSORPTION
A combination approach to bariatric surgery is one in which the procedure utilizes both restrictive and malabsorptive approaches. The Roux-en-Y Gastric Bypass procedure is the most popular technique, comprising 75% of bariatric surgical procedures. An average of 77% of excess body weight loss has been noted one year after surgery. Studies have shown that after 10 – 14 years, patients have maintained 60% of excess body weight loss. In a recent study of patients suffering from morbid obesity, Roux-en-Y Gastric Bypass has shown 83% resolution of type 2 diabetes, 85% resolution of obstructive sleep apnea, 75% resolution of hypertension and 93% improvement of hyperlipidemia and hypercholesterolemia.