Gastric banding has been around for about 20 years now and it is becoming an increasingly popular form of surgery. But just how does it work?
Weight loss surgery can be divided roughly into three different types:
- Restrictive surgery in which the quantity of food that you can eat is physically restricted.
- Malabsoption surgery in which there is no restriction of the quantity of food that you can eat but which re-routes that food through the digestive system so that you are only able to extract a small number of calories from food as it passes through the body.
- Combination surgery in which, as the name clearly suggests, a combination of both restrictive and malabsorptive surgical techniques are used.
Gastric banding is a form of restrictive surgery in which a band is placed around the top end of the stomach dividing the stomach into a small upper pouch holding approximately 50 ml and the remainder of the stomach holding something like 1000 ml.
The majority of gastric banding operations today use an adjustable band which can be tightened or loosened around the stomach to vary the size of the opening between the newly created small pouch and the bulk of the stomach. Adjustments are made by pumping saline in or out of an inner rubber ring within the band through a reservoir and access port which is inserted just under the skin during surgery and which is connected to the band by a length of tubing.
When you sit down to a meal following gastric banding you find that a very small quantity of food quickly fills the newly formed pouch and the stomach sends a message to the brain to say “stop, I’m full”. As a consequence you find that you are eating far smaller quantities of food without feeling hungry. At the same time however this smaller quantity of food is now insufficient to meet the body’s need for energy and so the body automatically starts to eat into its reserve of fat and you begin to lose weight.
During gastric banding the inner rubber ring will normally be given only a minimal inflation so that the opening between the small pouch and the bulk of the stomach is relatively large. Thus, although the flow of food between the two portions of the stomach will be restricted, you will still be able to eat a reasonable quantity of food as the contents of the small pouch empty quite quickly into the main stomach making room for your next meal.
The true secret to gastric banding lies in the ability of the surgeon, working with each individual patient, to gradually adjust the inflation of the band to find the point of restriction at which the patient is happy and weight loss is optimized.
Initial weight loss using gastric banding tends to be somewhat slower that that seen with many other forms of weight loss surgery (in particular with malabsorption and combination surgeries) but in the longer term the outcomes are comparable. Gastric banding patients find though that it is easier to maintain weight loss once their desired weight is reached.