Bariatric surgery is basically an operative procedure which aims at long term And sustainable weight loss for an individual. There are three types of procedures- Restrictive, Malabsorptive and Combined.
Procedures decrease the capacity of the stomach So that a person is able to eat less food at any given time. The normal capacity of an adult stomach is 1.5 – 2 litres. The stomach wall is elastic and can expand like a water filled balloon to accommodate a large volume of food. Restrictive procedures decrease this capacity of the stomach either temporarily or permanently.
Temporary or reversible procedures Include intra gastric balloon, adjustable gastric banding and gastric plication.
In Intragastric balloon, a deflated balloon made of silicon polymer is placed inside the stomach via endoscopy. This is then inflated with around 500 cc of saline so that it partially fills the stomach. This gives a sense of fullness to the person so that they eat less food.
Adjustable Gastric banding involves placing a silicone band around The upper part of the stomach which can be tightened by infusing saline through a tube. It also gives a feeling of fullness to the individual And decreases the capacity of food markedly.
In gastric plication, the shape of the stomach is modified by placing two layers of sutures on the lateral wall which gives it a tube like shape thus decreasing its capacity.
Sleeve gastrectomy is a permanent restrictive procedure In which around 80% of the stomach is removed with the help of a specialised instrument known as a laparoscopic stapling gun. This gun places 3 rows of titanium staples on either side and cuts in between which makes the procedure fast and bloodless. The entire upper part (fundus) and majority of the body of the stomach is removed. This not only reduces the size of the stomach but also reduces the amount of hunger hormone (ghrelin) produced in the body which helps in faster weight loss.
Malabsorptive procedures decrease the effective length of the small intestine For absorption of food. Purely Malabsorptive procedures have been abandoned because of the risk of protein and vitamin deficiency and nowadays combined procedures have become more popular because of the more effective weight loss and lesser side effects.
Combined procedures include gastric bypass and bilio-pancreatic diversion with duodenal switch. In gastric bypass, the upper part of the stomach is made into a small pouch of 30-50 cc capacity and a limb of the small intestine is directly joined to it thus bypassing 100-150 cm of the length of the proximal small intestine. The capacity to eat food is decreased markedly and also the absorption is limited so that there is a faster and more effective weight loss.
BPD-DS basically consists of a sleeve gastrectomy along with bypass of more than 200 cm of small intestine to decrease absorption of food.In combined procedures, The undigested food comes in direct contact with the small intestine which releases hormones which cause increased insulin production from the pancreas. This helps in better glucose metabolism and also leads to remission/cure of diabetes.
The mechanism of weight loss after bariatric surgery is mainly due to a combination of calorie restriction as a result of decreased intake/malabsorption and increased metabolic rate as a result of hormonal changes and increased insulin secretion. The total weight loss varies from 50-90% of the excess body weight depending on the type of procedure performed. The first 3-4 months is the period of rapid weight loss in which 50% of the extra weight is lost after which is the period of gradual weight loss which gradually plateaus off after a period of one year.
surgery has been proven to be the most effective treatment for morbid obesity and related comorbid diseases. It is the only medically approved treatment for long term durable weight loss. A number of other methods for weight loss have been recommended including dietary modification, behaviour and lifestyle changes, exercise and different drugs.
"These methods are efficacious for 5-7% of excess weight loss and in the majority of such people, the weight is regained after the therapy is stopped. In numerous comparative studies of Medical treatment versus bariatric surgery for weight loss, bariatric surgery has proved to have significantly greater weight loss than any other therapy. The long term follow up has shown the weight to be maintained over a period of 10-15 years following the procedure after which it is assumed to remain the same. Besides weight loss, this surgery has shown to be associated with significant reduction/resolution of associated comorbid illnesses including diabetes mellitus, hypertension, dyslipidaemia, osteoarthritis, fatty liver disease, PCOD, urinary incontinence and depression.