Monday, September 7, 2009

Bariatric Surgery Procedures | Malabsorptive Procedures | Restrictive Procedures | Hybrid Procedures | Bariatrics Surgery | Aastha Healthcare

Introduction
There are several different types of Bariatric weight loss surgical procedures, but they are known collectively as 'Bariatric surgery'. To understand this, the procedures can be grouped in three main categories below). The three types are:
  • Malabsorptive procedures: This surgery does focus at reducing the stomach size but they mainly aim on creating malabsorption. i.e. Biliopancreatic Diversion (Scopinaro procedure - rare)
  • Restrictive procedures: This kind of surgery primarily reduces the stomach size. There are three ways of doing this:
    • Vertical Banded Gastroplasty (Mason procedure, stomach stapling)
    • Adjustable gastric band (or "Lap Band")
    • Sleeve gastrectomy
  • Hybrid procedures: In this type, both the techniques of restriction and malabsorption are applied simultaneously. i.e. Gastric bypass surgery, like Roux-en-Y gastric bypass
    In this section, we will discuss all the procedures but only a surgeon can decide which one is suited the best for patient. Infact he is the only person who can tell whether the case could be handled laparoscopically or should be carried out as open surgery. This section is dedicated to providing you with the information to help you get familiar with Bariatric surgery

Malabsorptive procedures
This surgery focuses to reduce the stomach size but they mainly aim on creating malabsorption. So if the stomach pouch is smaller in size and if there is signifcant malabsorption, this will lead to impairment of nutrition absorption and assimilation. In other words Malabsorptive procedures alter digestion, thus causing the food to be poorly digested and incompletely absorbed so that it is eliminated in the stool.
Biliopancreatic Diversion: (BPD)

The original version of this procedure (without the duodenal switch) was developed by Dr. Scopinaro in Italy. This operation creates an impairment of nutrient absorption (called "malabsorption") as the primary factor in weight loss. This is done by removing about 2/3 of the stomach, and arranging the small intestine so that the section where food mixes with digestive juices is fairly short. This surgery is rare now because of problems with malnourishment. These operations may be more effective in achieving excellent weight loss in the extremely obese, but bring with them a higher rate of true malnutrition (malnutrition is very rare for those who undergo standard gastric bypass).


Restrictive procedures
There are several different types of Bariatric weight loss surgical procedures. Restrictive procedures are surgical procedures which primarily reduce the stomach size. They can be done in three ways. So the three surgical ways are:
  • Vertical Banded Gastroplasty (Mason procedure, stomach stapling)
  • Adjustable gastric band (or "Lap Band")
  • Sleeve gastrectomy
Vertical Banded Gastroplasty (VBG):

This operation emphasizes the volume restriction aspect of calorie control, by creating a tiny stomach pouch that exits into the lower stomach through a small fixed outlet that is reinforced by a permanent calibrated band on the stomach outlet. The operation was devised by Dr. Mason, one of the original Gastric Bypass surgeons, as he sought to devise the safest and most straightforward operation for morbid obesity. It is now an outmoded procedure because long term studies have demonstrated that it does not maintain weight loss as well as the Roux-en-Y gastric bypass.

Adjustable Gastric Band

The Laparoscopic Adjustable Silicone Gastric Band (LapBand®, Inamed) was approved by the FDA in June 2001, for use in treatment of Severe Obesity. The Lap-Band is a device designed to produce a small upper gastric pouch, and a narrow opening from it into the lower stomach. Surgeons use a silicone band to create a small pouch using the top part of the existing stomach. This limits food consumption without disrupting the normal progression of food through the digestive tract. It causes a sense of fullness after only a few bites of food, and it helps make the decision to reduce food intake, and to lose weight. It can be inserted laparoscopically. The biggest advantage is that it is a reversible process. This operation is especially attractive to persons who can spare only a small amount of time, and who need to return quickly to full activity. With one to two days hospitalization, a busy executive can return to his desk, and gain control over troublesome weight problems.

"Removable" in the list of key features refers to the fact that the Lap-Band can be removed from the patient with little residual impact on the stomach. This seems to be true even when the band has eroded into the stomach, or become infected, or slipped out of position. This is possible because the substance from which the band is made creates essentially no tissue reaction, so that the Band is not stuck in place over time. This feature also means that the Lap-Band procedure is "reversible" in a certain sense. We hasten to clarify that the Band would only be removed in our practice because of medical necessity, and that if it were not replaced by some other weight loss procedure that the patient would be guaranteed to experience significant weight regain.
This surgery as explained before, involves placement of a band around the outside of the upper stomach, to create an hourglass- shaped stomach, and to produce a small pouch with a narrow outlet. The special device used to accomplish this is made of implantable silicone rubber, and contains an adjustable balloon, which allows us to adjust the function of the band, without re-operation. Using thin surgical instruments and a small internal camera to monitor the operation, the surgeon places a silicone band without cutting or stapling. This pouch later limits the patient's food consumption without disrupting the normal progression of food through the digestive tract.
In some cases, the gastric band is connected via a small tube to a small reservoir that contains saline. This reservoir is placed under the skin of the upper abdomen. After surgery, the surgeon will
examine the patient to ensure that the band contains enough saline. It needs to be tight enough to allow for gradual weight loss while ensuring that the patient eats enough food for proper nutrition. Adjustments are typically made to the band one month after the procedure. Using a fine needle, the surgeon can add or remove saline to enlarge or shrink the band. The number of adjustments varies from person to person, but most patients need three to five before the band is at the ideal tightness. The length of this laparoscopic procedure is one to two hours. Because the stomach is not cut, stapled or opened there is less trauma to the body. The most common problem is a slippage of the stomach through the band, causing the upper stomach pouch to enlarge and obstruct, often requiring a revisional surgery, which can usually be done laparoscopically. For best success, frequent adjustments of the band are needed, and one must learn to change eating behaviour.
Sleeve Gastrectomy
A variation of the biliopancreatic diversion includes a duodenal switch. The part of the stomach along its greater curve is resected. The stomach is "tubulized" with a residual volume of about 150 ml. This volume reduction provides the food intake restriction component of this operation. This type of gastric resection is anatomically and functionally irreversible. The stomach is then disconnected from the duodenum and connected to the distal part of the small intestine. The duodenum and the upper part of the small intestine are reattached to the rest at about 75-100 cm from the colon.

HYBRID PROCEDURES
There are several different types of Bariatric weight loss surgical procedures, but Hybrid procedures are most commonly performed. In this type, both the techniques of restriction and malabsorption are applied simultaneously. I.e. Gastric bypass surgery, like Roux-en-Y gastric bypass. Now let us see this procedure in details.
Gastric Bypass Surgery
The newest and most exciting breakthrough in medical is gastric bypass surgery. Gastric Bypass is also called "Roux en-Y" procedure, named after the French surgeon, Dr. Roux, who first described this reconstruction in the 1800's. The bowel is cut, and reconstructed in a Y configuration, so that two parts of the GI tract can feed into one. This surgery involves creating a small (less than one ounce) vertically oriented stomach pouch, as well as a bypass of most of the stomach and a varying amount of small intestine. As a result, weight loss is accomplished both by restriction of food and by malabsorption of nutrients. The Gastric Bypass provides an excellent tool for gaining long-term control of weight, without the hunger or craving usually associated with small portions, or with dieting. Weight loss of 80 - 100% of excess body weight is achievable for most patients, and long-term maintenance of weight loss is very successful -- but does require adherence to a simple and straightforward behavioural regimen.
To understand what gastric bypass surgery is, it is important to know the normal course of digestion. In normal digestion, food passes through the stomach and enters the small intestine, where most of the nutrients and calories are absorbed. It then passes into the large intestine (colon), and the remaining waste is eventually excreted.
Now in this surgery, the surgeon staples across the top portion of the stomach to create a very small stomach pouch. The surgeon then connects the new stomach pouch to the small intestine, bypassing some of the upper and more absorptive part of the small intestine. The operation is complex and difficult, whether performed by an open incision, or by laparoscopy. It can be organized into three steps:
  • Division or partitioning of the stomach into two parts - an upper small pouch, and a lower, large pouch.
  • Creation of a Y-connection in the small bowel, to make a new end to connect to the stomach.
  • Connection of the new small bowel end to the upper stomach pouch, to bypass the stomach.
The first step is the creation of a small gastric pouch from the patient's original stomach. The pouch size is approximately 30-40 cc or slightly more than two ounces. The pouch is somewhat like an extension of the oesophagus but, when completed, is completely separated from the remainder of the stomach. The pouch is created along the more muscular side of the stomach and thus is less likely to stretch over time. This is the patient's new stomach and because it is significantly smaller than the original stomach far less food can be stored here before becoming full. In this way the feeling of fullness occurs much earlier when the patient eats and far less is eaten for each meal. Most patients who have undergone the gastric bypass indicate that they are far less interested in food and that their appetite is vastly diminished.
The next step in the procedure involves dividing the jejunum i.e. the second segment of the small bowel approximately 50-100 cm beyond its origin and connecting the bottom portion to the gastric pouch. Food now travels from the mouth to the oesophagus, into the gastric pouch and then immediately into the jejunum or Roux limb. Food no longer goes to the larger portion of the stomach. None of the stomach is removed and the secretions from the remainder of the stomach, now called the gastric remnant, continued to travel downstream into the first portion of the small bowel, called the duodenum, and combine with juices from the pancreatic gland and the liver.
The third step in the procedure involves the reconnection of the bowel (the first 50-100 cm of the jejunum and the duodenum containing the juices from the stomach, pancreas, and liver and called the biliopancreatic limb) to the segment of small bowel that was connected to the gastric pouch (the Roux limb). It is the distance between the gastric pouch and the place where the biliopancreatic limb is connected that determines the length of the bypass and the degree of malabsorption created by the operation. This distance is selected based on the patients BMI. The average length of the small bowel before surgery is thought to be approximately 18 ft. with the jejunum accounting for the first 2/5 of the small bowel. The length of the Roux limb that is created ranges from 75 cm to 180 cm (3-6 ft). The average time it takes to complete the Laparoscopic Roux-en-Y Gastric Bypass is approximately 2 hours. If the patient has gallstones, the surgeon may choose to remove the gallbladder as a preventative measure since there is a high incidence of gallstone formation upon weight loss.

This surgery reduces the amount of food eaten as well as decreases absorption of the food and calories consumed. So one will feel full more quickly than when their stomach was its original size, which reduces the amount of food the person will eat and thus the calories consumed. Bypassing part of the intestine also results in fewer calories being absorbed. This leads to weight loss. There is very little interference with normal absorption of food since the operation works by reducing food intake, and reducing the feeling of hunger. The result is a very early sense of fullness, followed by a very profound sense of satisfaction. Even though the portion size may be small, there is no hunger, and no feeling of having been deprived: when truly satisfied, you feel indifferent to even the choicest of foods. Patients continue to enjoy eating - but they enjoy eating a lot less. Ingestion of concentrated sugar is also essentially prohibited because doing so results in "dumping." Dumping is a group of unpleasant symptoms that resembles food poisoning (nausea, vomiting, diarrhea, abdominal cramps, flushing, and palpitations) that occurs when simple sugars enter the small intestine without first being properly digested by the stomach. Many people also report diminished appetite after Roux-en-Y gastric bypass, as well as a change in the taste of food. These are additional ways the gastric bypass causes weight loss. Following RNY surgery, patients are at risk for developing anemia because of poor absorption of iron and vitamin B12. Therefore, dietary supplementation of these nutrients is required. Poor absorption of calcium may also occur. Thus, calcium supplements must also be taken postoperatively.

For more information, kindly visit :
http://www.aasthahealthcare.com/Bariatric-Surgery-Procedures.htm

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