Understanding Bariatric surgery

The increased economic growth has brought prosperity no doubt but has also resulted in a higher incidence of diseases such as diabetes, hypertension, and of course obesity. With the higher consumption of highly refined and ‘junk’ foods, these diseases have reached epidemic proportions. Refined foods are high in carbohydrates and fats, but poor in protein, vitamins and minerals essential for optimal functioning of the body. The ‘junk’ foods are rich in sugar, fat and salt, which make it very palatable and so are consumed in large quantities.

Insulin is a hormone that is secreted by an organ called the pancreas in response to carbohydrate intake. It helps the body in proper utilization of carbohydrates which is its primary fuel; but when they are consumed in excess quantities, this hormone converts them to fats, which then accumulates in the body. Fat is a latent energy source of the body, they are the reserve fuel when the body runs out of carbohydrates. This happens in a state of starvation. With our regular civil supplies and ready access to food, starvation, of course, never happens. So, we end up accumulating the fats over the years. With the cumulative increase in fat, obesity occurs.

With the onset of obesity, the sensitivity of the body to insulin decreases and diabetes manifests. Other problems that occur include hyperlipidemia (increased cholesterol and fats in the blood), hypertension (increased blood pressure), obstructive sleep apnea (excess fat in the neck resulting in snoring and obstructed breathing), decreased bone density. Conditions such as PCOS and hypogonadism may be aggravated by obesity.

Obesity is graded by what is called body mass index (BMI), which is a ratio of weight to the height of a person. As the weight increases the BMI increases as the height remains constant in a fully grown human. Based on BMI, obesity is graded as follows

BMI	Category
< 18.5	Underweight
18.5 – 24.9	Normal
25.0 – 29.9	Overweight (Preobese)
≥ 30.0	Obese
30.0 – 34.9	Class I
35.0 – 39.9	Class II
≥ 40.0	Class III

It has been seen that the incidence of diabetes, hypertension etc, increases with the increase in the class of obesity. These diseases contribute significantly to reducing the life-span of a person as well as decreasing the quality of life. However, the good news is that by decreasing the BMI, this risk can be reversed.

BMI can be decreased by reducing the daily intake of calories. The cumulative net caloric deficit coupled with regular exercise reduces the weight. But our fast-paced life ridden with stress and easy accessibility to refined food has all but negated this option; moreover, the decreased bone density, breathing difficulty, joint pains restrict exercise. Even if one achieves weight loss, the moment they are off the diet, weight gain rebounds. These practical problems led scientists to investigate and find a solution, thus was born the field of bariatric surgery.

What is bariatric surgery?

The word bariatric derives from a combination of two Latin words – Baros meaning weight or heavy and iatros meaning doctor. This is an umbrella term for various operations done for morbid obesity which results in significant weight loss. These procedures date as far back as 1954, when Dr Kremen of University of Minnesota Hospital, US., performed the first jejuno-ileal bypass. Since then many a procedure have been devised for achieving weight loss. These procedures are the result of years of research in animal models and a thorough understanding of digestive physiology.

Bariatric procedures can be divided into

1. Those that restrict the consumption of food

2. Those that decrease the absorption of nutrients

3. A combination of these two

The various procedures include Adjustable gastric banding, Sleeve gastrectomy, Roux-en-Y gastric bypass (RYGB) and its variant Mini gastric bypass (MGB), Jejunoileal bypass and Biliopancreatic diversion-duodenal switch (BPD-DS).

Adjustable gastric banding

In this procedure, a band is placed over the top of the stomach near its junction with the esophagus (food pipe), which is adjustable to decrease the passage of food into the stomach and induce early satiety. The caliber of the band can be adjusted by filling it up with saline. With this procedure, a weight loss of 50% - 60% can be achieved in about 2 years.

Sleeve gastrectomy

This procedure involves the removal of 75% - 80% of the stomach, which reduces the size of the stomach. This results in early satiety and faster emptying of the stomach. Removal of the larger part of the stomach also lowers secretion of a hormone called Ghrelin which reduces hunger and decreases insulin secretion. This procedure achieves a 65% weight loss within six months.

Roux-en-Y Gastric bypass (Mini-gastric bypass)

This is both a restrictive and malabsorptive procedure. The stomach is reduced to a small pouch and part of the small intestine is joined with this pouch. This change in the configuration of the digestive organs results in changes in various gut-derived hormones which increase satiety decreases appetite and increases insulin sensitivity. The weight loss achieved here is 75% in the first six months.

Who requires bariatric surgery?

Class III obesity, Class II with complications such as diabetes, hypertension, OSA, and Class I with uncontrolled diabetes. Research has shown that in the Asian population, bariatric surgery may benefit even overweight patients of BMI 27.5 and above.

Pre-operative, operative and post-operative period – what to expect

The person who qualifies for bariatric surgery must have tried dietary restriction prior to the procedure. Before the operation is scheduled, a thorough interview by the physician, various blood investigations, x-rays of the chest, ultrasound of the abdomen and in some cases bone mineral density are done. This serves to optimize the condition prior to the procedure; also it helps the physician to choose the appropriate procedure.

The operations are performed laparoscopically (key-hole) where the intraabdominal organs are accessed with the help of only small holes on the abdomen. The procedures usually last from 2-4 hours. It is done in general anaesthesia where one remains completely unconscious in the entirety of the procedure.

In the postoperative period, ICU monitoring may be required to optimize recovery. Intake through the mouth is started the next day after an x-ray test. Once the oral intake is established, the patient is discharged in about 2-4 days.

Lifestyle modifications

Bariatric surgery initiates weight loss, but a good diet and regular exercise perpetuate it. Postoperatively, a diet plan is prescribed for about three months which takes a person through a graded increase in volume and consistency of foods. Physical rehabilitation with graded exercises improves form and function. These practices when inculcated results in reversal of diabetes, hypertension, OSA, osteoporosis, PCOS and hypogonadism.

Dr. Manoj Kumar R
Associate Consultant - Gi & General Surgery
MS (General Surgery), M.Ch (Surgical Gastroenterology) MRCS (Edinburgh)