Obesity and Laparoscopic Bariatric Surgery

Laparoscopic Bariatric Surgery for Morbid Obesity

Obesity

                                     

            Obesity became a major health problem throughout the world. Lifestyle changes with reduced physical activity and increased consumption of high calorie food led to the obesity pandemic. An individual is considered to be obese if body fat percentage is greater than 25% in males and 35 % in females. An individual’s weight should match his/ her height. Body mass index (BMI) is calculated using body weight and height. Based on BMI we can decide whether an individual’s weight is ideal, more or less for his/ her height. It is easy to calculate BMI.

            BMI = Body weight in kilograms/ square of height in meters = kg/ m². Based on BMI individuals are categorized as below

             If your BMI is ≥ 25 kg/m² (In western countries ≥ 30 kg/m²), then you are obese. Cut off limits for overweight and obesity are 23 and 25 kg/m² in Asians. In western countries these limits are 25 and 30 kg/m² respectively. If only BMI is taken into consideration, muscular individuals will wrongly be categorized as obese. So other parameters, like waist circumference and waist to hip ratio, are used to define obesity in addition to BMI. Waist circumference > 80 cm in females and > 90 in males and waist to hip ratio > 0.8 in females and > 0.9 in males indicate obesity. These may be better predictors of obesity than BMI in Asians.

Causes of obesity

            As the technology is advancing, comfort levels of the humans increased and the physical activity got reduced. In addition to this, easy availability of refined foods, fast foods and soft drinks resulted in daily consumption of high calories. Social and psychological factors also play an important role in food consumption and physical activity. In 90 percent of individuals obesity is due to excess eating and reduced physical activity. In remaining 10 percent endocrine, genetic problems are responsible. Certain individuals gain weight in spite of eating less. In fact even this limited eating is excess for them. In these individuals certain percentage of intake is converted into fat due to the effect of their genes.

            When we eat, food reaches stomach through a long tube (esophagus). How much we can eat at any given point of time depends on the capacity of stomach and our appetite. Stomach acts as a grinder and breaks the food particles into small pieces. From here the food reaches the small intestine. Small intestine has three parts - duodenum, jejunum and ileum. Most of the digestion of food and absorption of calories, vitamins and minerals occurs in the proximal small intestine. Absorbed excess calories are converted into fat and stored in fat cells. 

Figure 1 – Gastrointestinal tract + Hepatopancreticobiliary system

            One gram of carbohydrate (sugar) has 4 biological calories. One gram of fat (oil) has 9 biological calories. One biological calorie is equal to one kilocalorie. Those who indulge in heavy physical activity need approximately 3000 to 3500 Calories of energy per day. While those who lead sedentary life style need approximately 2000 Calories of energy per day. If anyone eats more carbohydrates or fats than he/ she needs then the energy derived from this excess food is converted into body fat. Excess calories derived from eating sweets, fries, chips, chocolates, pizzas, burgers, biscuits in addition to routine food, using excess oil in the food, and consuming soft drinks lead to gaining excess weight. In addition to this, consuming excess alcohol and lack of physical activity lead to obesity.

Problems associated with obesity

Obese individuals are at increased risk of developing type 2 diabetes and hypertension. Their blood cholesterol levels are usually higher than in non obese. This leads to fat accumulation in their blood vessels which increases risk of heart attack and stroke. Obese individuals may have joint pains and osteoarthritis as their joints have to bare excess weight. In addition they may snore during sleep with brief periods of cessation of breathing (obstructive sleep apnea) resulting in lack of sleep, excessive day time sleep. Obese individuals easily become tired and breathless even with limited physical activity. They are at increased risk of developing depression, gall stones, hernias etc. Obese females may have irregular periods and have higher incidence of abortions and difficult labor. Obesity and associated co-morbid conditions reduces life span by 5 to 20 years.

How to get rid of excess fat?

Reducing the excess weight is a big problem for several individuals. Calorie restriction, regular physical activity and commitment for the first two steps are important. First step is to cut down the daily calorie intake. Intake of carbohydrates, fats should be reduced. This means eating snacks like biscuits, cakes, cookies, fruits with excess sugars like mangoes, grapes, consuming soft drinks, eating potatoes, ice creams, fried food, sweets, chocolates, chips, tiffins with excess oil like poori, vada, using ghee or excess oil for cooking should be avoided or reduced drastically. Total food quantity should be reduced. Water, food with high protein content like egg white, lean meat, fish, green leafy vegetables and fruits with less sugar can be taken normally. Fruits and vegetables should be part of your daily menu. Whole grains should be consumed in place of refined grains. Skimmed milk, 1% fat milk or soya milk should be used in place of milk with high fat content. Regular walking and regular exercise will result in energy expenditure, weight loss and maintenance of weight loss. It will take just half minute to eat a sweet having 200 calories. But to get rid of that energy you need to walk for 1 hr or run for 15 min.

Role of medicines in the treatment of obesity

There are several anti obesity medicines in which only orlistat has FDA (Food and Drug Administration) approval. These medicines are useful to increase the weight loss only in those individuals who are already losing weight by food restriction and exercise.

Sibutramine, an anti-obesity drug which act on brain and reduces appetite, is banned in India, USA and other countries due to its cardiovascular side effects. Side effects of sibutramine include increased blood pressure, insomnia, headache, constipation, dryness of mouth, risk of heart attack and stroke. Orlistat prevents absorption of up to 30 percent of fat in food by antagonizing the action of pancreatic lipase enzyme in digestive juices. It has no effect on digestion & absorption of carbohydrates. So it is not useful for those consuming excess sugars and eating very excess fat foods. As certain percentage of fat is not absorbed, side effects include steatorrhoea (foul smelling sticky stools because of presence of undigested fat in stools) and sometimes incontinence of stools. According to several reports orlistat has been implicated in liver failure, acute kidney injury and pancreatic injury.

Endoscopic methods of treatment for obesity

Extensive research is being carried out on endoscopic bariatric procedures as they are more effective than medicines and probably safer than surgery. Certain procedures like intra gastric balloon are useful as a bridge to bariatric surgery as they reduce surgical risk by reducing patient's weight to certain extent before surgery. Presence of balloon inside the stomach reduces its effective volume. Individual with intra gastric balloon gets early satiety after taking even small quantity of food. Initially upper gastrointestinal endoscopy is done to rule out conditions like reflux esophagitis, hiatus hernia, peptic ulcer disease and gastric outlet obstruction. Balloon is introduced into stomach and filled with 500 ml normal saline and 10 ml methylene blue solution. Balloon has to be removed after 6 months. If it is left beyond 6 months there is risk of spontaneous deflation, intestinal obstruction. If patient has discomfort or vomiting, it may have to be removed earlier. Intra gastric balloon is not suitable as a primary bariatric procedure due to its limited durability.

Endoluminal suturing procedures are used as early intervention endoscopic procedures in Grade 1 obesity patients who do not qualify for bariatric surgery. They are also used as revisional procedures after failed bariatric surgery. They can’t be used as primary bariatric procedures as the degree of weight loss is inadequate after these procedures. Endoscopic staplers function similar to adjustable gastric band. These devices are still in trials. They can be used as primary bariatric procedures in future if they are successful in trials.

Bariatric surgery

These are operations performed on stomach and small intestine. These operations work on the principle of either reducing the digestion and absorption of food and/or limiting the amount of food intake at any given point of time. As a result gradual weight loss is achieved towards ideal body weight.

Majority of the obese individuals fail to reduce weight by food restriction and regular exercise. Even if they lose weight initially after diet and exercise regimen, eventually they regain weight. Inability to control high calorie intake, inability to exercise regularly or failure to exercise because of joint problems are some of the reasons for failure. Bariatric surgery is beneficial for such individuals.

Eligibility for bariatric surgery

Obese individuals with BMI ≥ 32 kg/m² with at least two significant medical co-morbid conditions or BMI ≥ 35 kg/m² even without co-morbid conditions are eligible for laparoscopic bariatric surgeries. In western countries cut off limits of BMI are 35 kg/m² and 40 kg/m² respectively.  In Asians with central obesity and at least two significant medical co-morbid conditions the cut off limit is further reduced to 30 kg/ m². Higher BMI increases the incidence and severity of co-morbid conditions. If these BMI categories are strictly applied to decide patients eligible for bariatric surgery then many obese individuals will not have effective therapeutic options.

Obese individuals should have tried sincerely but failed to reduce weight by food restriction or exercise before taking a decision to undergo bariatric surgery. They should understand various surgical options and the need to take precautions in the food intake after surgery. After bariatric operations they will be on lifelong vitamin and mineral replacement. They need to be on regular follow up at specified intervals.

Types of laparoscopic bariatric surgeries

These are divided into following categories.

(1) Purely restrictive operations

Eg – Laparoscopic sleeve gastrectomy (Lap SG), laparoscopic adjustable gastric banding (LAGB)

(2) Restrictive and mal-absorptive operations

Eg – Laparoscopic roux-en-y gastric bypass (Lap RYGB - Most popular bariatric surgery)

(3) Mostly mal-absorptive operations

Eg – Laparoscopic long limb roux–en–y gastric bypass (Lap LRYGB), laparoscopic bilio-pancreatic diversion with duodenal switch (Lap BPD-DS).

Presence of certain factors makes patients more or less suitable to one or other type of bariatric surgery. For example Lap RYGB operation is not suitable in patients who need to take pain killers on regular basis. Patients at extremes of age, prior abdominal surgeries with extensive adhesions are suitable to purely restrictive operations. Patients with large hiatus hernia or paraesophageal hernia, who cannot come for regular follow ups for band adjustments, who are super obese are not suitable for LAGB.

Mechanism of weight loss after bariatric surgery

In restrictive operations the stomach size is reduced or its size is restricted to receive only small amount of food. As a result food intake is restricted at any given point of time. These are effective if BMI is less than 50 kg/ m². Postoperative food selection plays a major role in success of restrictive operations. Patients should be willing to change their food habits after these operations.

In mal-absorptive operations, in addition to reducing the size of stomach, proximal part of the small intestine where most of digestion and absorption of food occurs is bypassed so that food will reach distal part of the small intestine directly. In these operations in addition to food restriction at any given point of time, digestion and absorption of food is reduced. These are effective in any obese individual who is eligible for bariatric surgery. These are complex surgeries and technically demanding. Vitamin and mineral deficiencies are more after mal-absorptive operations. Nevertheless they are more effective than restrictive surgeries in inducing weight loss and they have well defined role as bariatric surgeries.

In restrictive + mal-absorptive operations like gastric bypass, 50 to 250 cm of proximal intestine is bypassed. In mostly mal-absorptive operations extensive length of small intestine is bypassed. This bypass is in addition to a restrictive component created in the stomach.

Bariatric operations act on the root causes of fat accumulation in the body. Depending on the type of operation excess weight loss will be 4 to 7 kg per month. In 6 months to 2 years weight reaches a point nearer to ideal weight. Weight will not go below ideal body weight usually. So there is no need to fear that individuals will become skinny.

Unlike in liposuction, excess fat is not removed in bariatric surgeries. As the metabolism is controlled, excess fat gradually comes down in due course of time. In liposuction, excess accumulated fat is removed but main reason for fat accumulation is not addressed. So individuals may regain weight. Operations aimed at removal of excess accumulated fat are mainly cosmetic and have important role in specific situations.

Advantages of doing bariatric surgery by laparoscopic method

Bariatric surgery is performed either by open method (cutting the tummy) or by laparoscopic method (putting small holes in the tummy). Compared to normal individuals, obese individuals are at high risk of developing postoperative lung collapse, lung infections, deep vein thrombosis (blood clots in legs), wound infections and incisional hernias. Compared to open surgery, these complications are significantly less after laparoscopic surgery. After laparoscopic bariatric surgery patient can walk within 2 days, can go home within 5 days and can resume normal activities in 2 weeks. Cosmetically it is excellent as only small holes are created to perform surgery. Because of these uses, laparoscopic method for bariatric surgeries became popular.

 For further details or doubts please contact  Dr. Amar 
                  Mobile : +91 9676675646  
                  email   : amar.venn@gmail.com
                 website  : www.drvamar.com