Thursday, April 18, 2013

Bariatric Surgeries Explained


Bariatric surgery includes a variety of procedures performed on people who are obese. Weight loss is achieved by reducing the size of the stomach with a gastric band or through removal of a portion of the stomach (sleeve gastrectomy or biliopancreatic diversion with duodenal switch) or by resecting and re-routing the small intestines to a small stomach pouch (gastric bypass surgery).
Long-term studies show the procedures cause significant long-term loss of weight, recovery from diabetes, improvement in cardiovascular risk factors, and a reduction in mortality of 23% from 40%. However, a study in Veterans Affairs (VA) patients has found no survival benefit associated with bariatric surgery among older, severely obese people when compared with usual care, at least out to seven years.
The American Society for Metabolic and Bariatric Surgery  (ASMBS) is the largest society of healthcare professionals dedicated to the safe and effective provision of bariatric surgery. The vision of the Society is to improve public health and well being by lessening the burden of the disease of obesity and related diseases throughout the world. Founded in 1983, the purpose of the society is to advance the art and science of metabolic and bariatric surgery by continually improving the quality and safety of care and treatment of people with obesity and related diseases by:
The U.S. National Institutes of Health recommends bariatric surgery for obese people with a body mass index (BMI) of at least 40, and for people with BMI 35 and serious coexisting medical conditions such as diabetes. However, research is emerging that suggests bariatric surgery could be appropriate for those with a BMI of 35 to 40 with no comorbidities or a BMI of 30 to 35 with significant comorbidities.




 From Wikipedia

Contents






Classification of surgical procedures
Procedures can be grouped in three main categories: Standard of care in the United States and most of the industrialized world in 2009 is for laparoscopic as opposed to open procedures. Future trends are attempting to achieve similar or better results via endoscopic procedures.

Predominantly malabsorptive procedures
In predominantly malabsorptive procedures, although they also reduce stomach size, the effectiveness of these procedures are derived mainly from creating a physiological condition of malabsorption.
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Diagram of a biliopancreatic diversion.

Biliopancreatic Diversion
This complex operation is termed biliopancreatic diversion (BPD) or the Scopinaro procedure. The original form of this procedure is now rarely performed because of problems with malnourishment. It has been replaced with a modification known as duodenal switch (BPD/DS). Part of the stomach is resected, creating a smaller stomach (however the patient can eat a free diet as there is no restrictive component). The distal part of the small intestine is then connected to the pouch, bypassing the duodenum and jejunum.
In around 2% of patients there is severe malabsorption and nutritional deficiency that requires restoration of the normal absorption. The malabsorptive effect of BPD is so potent that those who undergo the procedure must take vitamin and dietary minerals above and beyond that of the normal population. Without these supplements, there is risk of serious deficiency diseases such as anemia and osteoporosis.  Because gallstones are a common complication of the rapid weight loss following any type of bariatric surgery, some surgeons remove the gallbladder as a preventive measure during BPD. Others prefer to prescribe medications to reduce the risk of post-operative gallstones. Far fewer surgeons perform BPD compared to other weight loss surgeries, in part because of the need for long-term nutritional follow-up and monitoring of BPD patients.
Jejunoileal bypass
This procedure is no longer performed.
Endoluminal sleeve
A study on humans was done in Chile using the same technique, however the results were not conclusive and the device had issues with migration and slipping. A study recently done in the Netherlands found a decrease of 5.5 BMI points in 3 months with an endoluminal sleeve.
Predominantly restrictive procedures
Procedures that are solely restrictive, act to reduce oral intake by limiting gastric volume, produces early satiety, and leave the alimentary canal in continuity, minimizing the risks of metabolic complications.
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Diagram of a vertical banded gastroplasty.

Vertical Banded Gastroplasty
In the vertical banded gastroplasty, also called the Mason procedure or stomach stapling, a part of the stomach is permanently stapled to create a smaller pre-stomach pouch, which serves as the new stomach.
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Diagram of an adjustable gastric banding.

Adjustable gastric band
The restriction of the stomach also can be created using a silicone band, which can be adjusted by addition or removal of saline through a port placed just under the skin. This operation can be performed laparoscopically, and is commonly referred to as a "lap band". Weight loss is predominantly due to the restriction of nutrient intake that is created by the small gastric pouch and the narrow outlet. It is considered one of the safest procedures performed today with a mortality rate of 0.05%. 


Sleeve gastrectomy
Sleeve gastrectomy, or gastric sleeve, is a surgical weight-loss procedure in which the stomach is reduced to about 15% of its original size, by surgical removal of a large portion of the stomach, following the major curve. The open edges are then attached together (typically with surgical staples, sutures, or both) to leave the stomach shaped more like a tube, or a sleeve, with a banana shape. The procedure permanently reduces the size of the stomach. The procedure is performed laparoscopically and is not reversible.
This combined approach has tremendously decreased the risk of weight loss surgery for specific groups of patients, even when the risk of the two surgeries is added. Most patients can expect to lose 30 to 50% of their excess body weight over a 6–12 month period with the sleeve gastrectomy alone. The timing of the second procedure will vary according to the degree of weight loss, typically 6 – 18 months.
·         Stomach volume is reduced, but it tends to function normally so most food items can be consumed in small amounts.
·         Removes the portion of the stomach that produces the hormones that stimulates hunger (Ghrelin), although the durability of this removal has yet to be confirmed.
·         Dumping syndrome is less likely due to the preservation of the pylorus (although dumping can occur anytime stomach surgery takes place).
·         Minimizes the chance of an ulcer occurring.
·         By avoiding the intestinal bypass, the chance of intestinal obstruction (blockage), anemia, osteoporosis, protein deficiency and vitamin deficiency are significantly reduced.
·         Very effective as a first stage procedure for high BMI patients (BMI >55 kg/m2).
·         Limited results appear promising as a single stage procedure for low BMI patients (BMI 35–45 kg/m2).
·         Appealing option for people with existing anemia, Crohn's disease, irritable bowel syndrome, and numerous other conditions that make them too high risk for intestinal bypass procedures.

Intragastric Balloon (gastric balloon)
Intragastric balloon involves placing a deflated balloon into the stomach, and then filling it to decrease the amount of gastric space. The balloon can be left in the stomach for a maximum of 6 months and results in an average weight loss of 5–9 BMI over half a year. While not yet approved by the FDA the intragastric balloon is approved in Australia, Canada, and Mexico, India and several European and South American countries. The intragastric balloon may be used prior to another bariatric surgery in order to assist the patient to reach a weight which is suitable for surgery, further it can also be used on several occasions if necessary.
Gastric Plication
Basically, the procedure can best be understood as a version of the more popular gastric sleeve or gastrectomy surgery where a sleeve is created by suturing rather than removing stomach tissue thus preserving its natural nutrient absorption capabilities. Gastric Plication significantly reduces the volume of the patient's stomach, so smaller amounts of food provide a feeling of satiety. The procedure is producing some significant results that were published in a recent study in Bariatric Times and are based on post-operative outcomes for 66 patients (44 female) who had the gastric sleeve plication procedure between January 2007 and March 2010. Mean patient age was 34, with a mean BMI of 35. Follow-up visits for the assessment of safety and weight loss were scheduled at regular intervals in the postoperative period. No major complications were reported among the 66 patients. Weight loss outcomes are comparable to gastric bypass.
The study describes gastric sleeve plication (also referred to as gastric imbrication or laparoscopic greater curvature plication) as a restrictive technique that eliminates the complications associated with adjustable gastric banding and vertical sleeve gastrectomy—it does this by creating restriction without the use of implants and without gastric resection (cutting) and staples.

Mixed procedures
Mixed procedures apply both techniques simultaneously.
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Roux-en-Y gastric bypass.



Gastric bypass surgery
A common form of gastric bypass surgery is the Roux-en-Y gastric bypass. Here, a small stomach pouch is created with a stapler device, and connected to the distal small intestine. The upper part of the small intestine is then reattached in a Y-shaped configuration. The gastric bypass had been the most commonly performed operation for weight loss in the United States, and approximately 140,000 gastric bypass procedures were performed in 2005. Its market share has decreased since then and by 2011, the frequency of gastric bypass was thought to be less than 50% of the weight loss surgery market. A factor in the success of any bariatric surgery is strict post-surgical adherence to a healthier pattern of eating.
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Diagram of a sleeve gastrectomy with duodenal switch.

Sleeve Gastrectomy with Duodenal Switch
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.
Implantable gastric stimulation
This procedure where a device similar to a heart pacemaker is implanted by a surgeon, with the electrical leads stimulating the external surface of the stomach, is being studied in the USA. Electrical stimulation is thought to modify the activity of the enteric  nervous system of the stomach, which is interpreted by the brain to give a sense of satiety, or fullness. Early evidence suggests that it is less effective than other forms of bariatric surgery.
                


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