WEIGHT LOSS SURGERYPATIENT INFORMATION
COMPLIED BY:
Dr Costa Karihaloo, Dr Jon Gani and Ms Cathy Harbury
Introduction
Morbid obesity is an increasingly common problem in Australia and the developed world. It is defined as having a body mass index (BMI) of more than 40. The BMI is calculated by dividing weight (in kilograms) by height (in metres) squared. For example, a person who weighs 120 kg and who is 160 cm tall has a BMI of 120 1.62 = 120 2.56 = 46.875. Morbid obesity can also be defined as being more than 45 kg above ideal body weight. Morbid obesity is associated with disability, ill health and increased mortality; it reduces life expectancy by 5 to 20 years.
The causes of morbid obesity are not well understood, but primarily include environmental factors (e.g. fast foods, lack of exercise). Genetic and biochemical factors controlling appetite and the way that the body handles energy are also involved. What is increasingly well acknowledged is that once an individual becomes morbidly obese, the typical options for weight loss (diet and exercise) are ineffective in 98% of cases; studies have now shown that weight-loss surgery is the only way for a morbidly obese individual to lose weight permanently and reverse some of the negative health effects associated with their weight.
There are a large number of physical illnesses associated with morbid obesity. These include diabetes, high blood pressure, heart disease, sleep apnoea, blood clots, osteoarthritis, peripheral oedema, leg ulcers, gastro-oesophageal reflux, gallstones, reduced fertility, and some cancers (e.g. breast and colon). Morbid obesity also has a lot of psychological morbidity associated with it, with significant social and economic discrimination and effects on self-esteem.
Weight-loss surgery has been around for 50 years. Like most other surgery it has become safer and is increasingly performed using keyhole surgery. However, like all surgery, it is associated with some degree of risk. There are several operations which may be performed. These may be divided into those that restrict the volume of food which can be eaten, and those that cause malabsorption of ingested food. The restrictive operations are Vertical Banded Gastroplasty (VBG, “stomach stapling”), Laparoscopic Adjustable Gastric Banding (Lap-band), Sleeve gastrectomy, and Gastric Bypass. The malabsorptive operations are Bilio-Pancreatic Diversion (BPD) and Duodenal Switch. Malabsorptive surgery is rarely performed in Australia as it carries a high risk of life-threatening complications. Of the restrictive operations, the VBG has been performed for the longest time, however the lap-band operation has become very popular due to its relative safety, simplicity and reversibility. All forms of weight-loss surgery have been shown to improve some of the health problems associated with morbid obesity especially diabetes, high blood pressure, sleep apnoea, infertility and degenerative joint disease. Weight-loss surgery has been shown to improve quality of life and reduce the risk of death.
Weight-loss surgery may be an option for a morbidly obese individual (BMI>40), or for an obese individual (BMI>35) with significant health problems related to their weight. However, surgery alone does not make people lose weight: surgery is a tool that the individual can use to lose weight. Successful surgery requires complete understanding of the procedure and commitment to lifestyle changes and follow-up. The decision to undergo surgery cannot be taken lightly, as severe complications and even death can occur.
Vertical Banded Gastroplasty (“stomach stapling”)
This was the most commonly performed weight-loss operation in Australia prior to the lap-band. There are many people who have had successful and durable weight-loss with it. It is a restrictive operation: a small stomach pouch is created by stapling off the upper part of the stomach, which fills quickly and gives the sensation of satiety, thereby reducing the amount of food eaten. High calorie liquids must be avoided as they pass straight through the pouch. Vitamin supplements must be taken as the volume of food consumed is significantly reduced (to about a cupful per sitting). There are problems with this operation which have led to it being more or less replaced by Lap-Banding: the staple line would sometimes breakdown with time, leading to a loss of restriction, and the outlet from the pouch had to be just right – if it was too tight there would be problems with vomiting, too loose and there would be insufficient restriction. Overall, studies report 15-20% weight loss at 10 years post surgery.
Laparoscopic Adjustable Gastric Band (“Lap-Band”)
The gastric band has become the most commonly performed operation for weight loss in Australia. It is a restrictive operation which is performed by keyhole (laparoscopic) surgery. A silicone band is placed around the very top of the stomach. This creates a tiny gastric pouch above the band. This reduces the amount of food that can be eaten and the speed at which it can be consumed. It works best with solid food, which stretches the wall of the pouch, triggering a feeling of satiety. With time, the opening between the pouch and the rest of the stomach may enlarge, leading to less feeling of restriction. The advantage of the band over VBG is that the size of this opening may be adjusted. This is done by injecting fluid into the access port which is secured onto the muscle of the abdominal wall, under the skin and fat. This procedure usually needs to be done three or four times in the first year after surgery, and roughly annually after that. The lap-band is the safest weight-loss operation and completely reversible, meaning that the band can be removed and the stomach returns to its normal state. However, of all the bariatric (obesity) operations, it is the least effective in terms of amount of weight lost and requires the greatest degree of follow-up. Once a lap-band is inserted, a patient must visit the dietician and surgeon regularly for the rest of their life, or until the band is removed. Current evidence suggests that about 10% of people require further surgery down the track. Initially this is most commonly for problems relating to the port such as infection or migration. Later on (3 to 5 years) problems with the band such as slippage of the stomach under the band (leading to reflux and vomiting) or erosion of the band into the stomach (leading to loss of restriction and late port infection), may require further keyhole surgery to remove the band. Problems with the band do not necessarily prevent any further weight-loss surgery from being performed later on, but they do make subsequent operations more risky.
Weight loss with the lap band can be expected to be 50-55% of the excess body weight (the weight above ideal weight - BMI of 25). This occurs gradually over 3 years. In 25% of people, for reasons that are poorly understood, the lap-band does not give adequate weight loss. A smaller proportion of people do not tolerate having the band in place – either because of the feeling of restriction, or because of food getting stuck. In these cases the band may need to be removed.
In order for the lap-band to work, strict dietary instructions must be adhered to. The operation itself (which takes about an hour) and the initial hospitalisation (usually about 2-4 days) is a very small part of the overall process. For the first two weeks after surgery a liquid only diet must be consumed, while the swelling around the band settles down. The following two weeks progress to a mushy pureed diet. After that, the lap-band diet is started. The quantity of food is greatly reduced, so regular visits to the dietician are required to ensure that sufficient nutrients are taken in. Meal size is roughly a cupful, or one entrée. This must be eaten slowly and chewed well, or food is liable to get stuck leading to pain and vomiting. The band only works with solid food, so drinking must be either before or after the meal, not with the meal. About 2/3 of people find that they cannot eat certain foods because they get stuck. This is most common with red meat and chicken. Fizzy drinks must be avoided as they can cause pain from stretching of the pouch. Alcohol is discouraged because of its high caloric value.
Band adjustments start at six weeks after the operation. They are done with a needle by the surgeon in the rooms. Sometimes the port cannot be accessed easily, and the adjustments need to be done with X-ray guidance. The procedure is about as painful as giving blood, and usually takes a minute. The timing of the adjustments is determined by the feeling of restriction that the band is giving, and by the progression of weight loss. Generally speaking, as the feeling of restriction lessens, the volume eaten increases and the weight loss tapers… this indicates to us that it is time for a band fill. The number of fills required varies with the individual, but is usually four in the first year, and one or two the year after that. Eventually, fills are not required, as weight loss goals have been reached. Overfilling the band can damage the band, but more significantly can cause vomiting which increases the likelihood of the band slipping.
Sleeve Gastrectomy
This is a newer form of weight-loss surgery. It is also called “vertical gastrectomy” and “tube gastrectomy”. It is a restrictive operation and is performed by keyhole (laparoscopic) surgery. About three-quarters of the stomach is removed and the remaining stomach has a volume of less than 100 ml. This is a non-reversible procedure.
There are several benefits to this approach:
(1)Current evidence suggests that weight-loss is slightly greater and slightly quicker than with the lap-band – roughly 60% of excess weight lost at 2 years.
(2)The stomach removed is responsible for secreting a hormone (ghrelin) which partly controls hunger, thus weight-loss is accompanied by less feeling of hunger than the lap-band.
(3)There is no need for long-term follow-up for adjustments (it is not an adjustable procedure) or nutritional problems.
(4)There is generally no food intolerance, unlike the lap-band where most people are unable to eat certain kinds of food.
There are several significant concerns:
(1)There is no long-term data to confirm that the weight loss is durable.
(2)There is a significant (1-2%) risk of leakage from the long line of staples, and this can be a very serious complication requiring open surgery and a long stay in hospital (months).
(3)A large proportion of people (20%) develop reflux symptoms, which may require medication or even further surgery to control.
Historically, the Sleeve Gastrectomy was developed as the first part of two-stage surgery. The Sleeve Gastrectomy would be performed to allow initial weight-loss, which would then make a second operation (such as duodenal switch or gastric bypass) much easier to perform. The excellent weight-loss results led to it being adopted as a stand-alone procedure, however, the option of having a second operation should weight-loss be inadequate or should there be long-terms problems with weight regain remains.
The preparation for surgery is more or less the same as for the lap-band. It involves attending a seminar, discussion with the dietician, psychologist, nurse and surgeon, and a two-week course of Optifast. The surgery is performed through five keyhole incisions… although one is made slightly bigger to remove the excised stomach. The surgery takes between one and two hours. A clear liquid diet is started gradually from the first day after the operation. Antacid medication is also started and usually continued for four weeks. If abdominal drains are used, they may be removed after two to three days. Total hospital stay is between four days and a week. A clear fluid diet is continued for one week, followed by a fluid diet for one week. This progresses to a soft diet for one week and then a normal diet may be commenced.
After the initial convalescence, there is no need for any further follow-up with the surgeon, however the dietician may be useful for ongoing advice and to monitor nutritional intake.
Gastric Bypass
This operation is the most effective weight-loss operation. It is essentially a restrictive operation, where the stomach is partitioned into a small pouch. This pouch then empties into small intestine which is joined onto it (a so-called “roux” limb, hence the name roux-en-y gastric bypass). As well as reducing the amount of food eaten, the passage of undigested food into the small intestine exerts powerful hormonal influences which create a feeling of satiety. The amount of intestine bypassed is not enough to cause any nutritional problems from malabsorption, but iron and vitamin B12 supplementation must be taken indefinitely (the stomach is responsible for aiding their absorption).
Weight loss is usually 70% of the excess body weight, and it is very uncommon for people not to lose weight after gastric bypass. It is also the most effective operation in terms of curing co-morbidities, such as type 2 diabetes. There are significant risks associated with the operation. Currently in Australia there are very few centres with experience at performing the surgery laparoscopically, thus the surgery is usually done through a large incision. The incision is painful, which may lead to problems with breathing in the post-operative period. In the longer-term there is a high incidence of hernia formation through the wound (15-20%), which usually requires surgery to correct. The surgery involves creating several anastamoses (joins) in the bowel and these may leak (1-2%). Anastamotic leak may have catastrophic consequences including prolonged stay in Intensive Care, need for re-operation, and even death. Once the joins have healed and the patient leaves hospital there is an ongoing risk of forming internal hernias which can cause bowel obstruction (3-5% lifelong) and of bleeding from ulcers forming at the anastamoses. Blood tests should be performed at least annually to check for iron and vitamin B12 deficiency.
Which operation is right for me?
In Australia, the lap-band operation is by far the most commonly performed weight-loss operation. This is because it is the simplest and safest operation. It is a reversible procedure, so it does not preclude other operations being performed should weight loss prove inadequate. Many surgeons recommend the lap-band as the first operation any morbidly obese patient should have.
There are several cautions:
(1)If a person lives a long way away from their surgeon attending follow-up becomes difficult, and without rigorous follow-up gastric banding does not work.
(2)If a person is super-obese (BMI>50), lap-banding will often fail in reducing weight to a BMI of less than 40. It will still have a beneficial effect on co-morbidities. Super-obese individuals who wish to have lap-banding performed should be prepared to consider further surgery down the track.
(3)The lap-band requires significant changes to eating behaviour, not only the quantity of food eaten, but the types of food which can be consumed, and the time taken to eat. Successful weight loss with the band requires motivation and a commitment to lifestyle change.
(4)At the moment we have extremely limited resources to perform any bariatric surgery in the public sector: we cannot guarantee that a person waiting for surgery in the public sector will ever be operated on. We only perform surgery on people in the private sector with full private insurance.
What is life like after surgery?
Gastric reduction limits the quantity of food you can eat at any one time. By eating only at meal time and only until you feel full, your daily food intake should be decreased enough to provide a weight loss of approximately 1 kilogram per week during the first six months after surgery. It is clear however, that for you to achieve the most success with weight loss, you must make changes in your daily food habits which allow maximal effectiveness of the gastric reduction surgery. These changes include:-
(1)Eating three meals a day and eating only at meal times.
(2)Eating solid foods at meals. Solid foods will keep you feeling full longer.
(3)Eating slowly and chewing foods until they are of a mushy consistency. Meals should be eaten at a leisurely pace (at least 30 minutes). This helps you chew foods better and helps prevent over eating.