Gastric banding, which is a type of purely restrictive weight loss surgery (that is to say that it works solely by restricting the quantity of food which can be consumed), includes both vertical banded gastroplasty and adjustable gastric banding. In the case of lap band surgery we are looking only at adjustable gastric banding.

The lap band system comprised a silicone ring with an inflatable inner lining which is designed to be placed around the upper section of the stomach. The band is then connected by a length of tubing to an access port which is placed just below the surface of the skin during surgery.

The placement of the band high up on the stomach creates a small pouch at the top of the stomach to hold food, with the bulk of the stomach now being below the band. The placement of the band also creates a very small opening, or stoma, between the two sections of the stomach and the size of this opening can be controlled by introducing liquid (normally saline) into, or removing liquid from, the inflatable inner ring of the band through the access port.

During lap band surgery the inner band is normally only given a very minimal inflation producing a relatively large opening between the two sections of stomach. Although the term relative is used here it should be noted that the newly created small stomach pouch and the opening between the sections of the stomach are in reality both very small.

In the period immediately following lap band surgery, the inner ring will be gradually inflated until a point is reached at which weight loss is optimized and the patient is comfortable with the size and frequency of meals that he/she can eat.

Restrictive forms of weight loss surgery are generally easier to perform than other procedures and lap band surgery is often performed laparoscopically which results in a reasonably short stay in hospital and a fairly fast post-operative recovery. This type of surgery also avoids many of the nutritional problems seen in malabsorption surgery (gastric bypass surgery in which food is re-routed through part of the small intestine). Finally, lap band surgery is totally reversible and removal of the band will result in the stomach returning to its normal size.