الفهرس 
Causes and ClassificationOnly 14 pages are availabe for public view
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Abstract
Obesity is an excess of body fat that frequently results in a significant impairment of health. It is a chronic, lifelong, genetically related, life-threatening disease of excessive fat storage.In a practical setting, it is difficult to determine this directly. Therefore, obesity is typically assessed by BMI (body mass index) and in terms of its distribution by the waist circumferenc. The use of the Body Mass Index (BMI) to define and classify obesity has been adopted widely and although BMI represents a crude measurement, it correlates well with the amount of body fat in the majority of individuals.
BMI is represents weight in Kilograms divided by height in meters squared (kg/m2). It is easy to identify patients who are underweight (BMI < 18.5 kg/m2), normal weight (BMI 18.5 to 24.9 kg/m2), overweight (BMI 25 to 29.9 kg/m2), obese (BMI 30 kg/m2), or extremely obese (BMI 40 kg/m2), BMI > 60 kg/m2 are considered morbidly super-obese persons. WHO estimates that a billion people worldwide are overweight (BMI greater than 25), and 300 million people are obese (BMI greater than 30 kg/m2.
Obesity is a multi-factorial disease, it develops from integration of genetic, environmental, social, behavioral, physiological, metabolic, neuro-endocrinal and psychological factors, the exact etiology is unknown, and it is associated with many health hazards, such as type 2 diabetes mellitus, cardiovascular diseases, hypertension, stroke, osteoarthritis, sleep apnea, and nonalcoholic fatty liver disease.
Effective weight loss therapy can reverse many of the adverse effects of severe obesity. Available therapies include lifestyle changes (diet and exercise), pharmacologic therapy, behavioral modification, and surgery. The most effective treatment for obesity is bariatric surgery.
Recent estimates by the World Health Organization suggest that if current trends continue, obesity will affect an estimated 1.5 billion people by 2015. Indeed, the close association between obesity and the increased incidence and prevalence of obesity-related co-morbidities, mortality, decreased quality of life, and increased health care expenditure has made obesity a worldwide public health priority. Behavioral and pharmacological treatment efforts had done little effect, particularly in severe obesity (BMI ≥35 kg/m2) and super obesity (BMI ≥50 kg/m2) within the past decade, the volume of bariatric surgery has increased by 900% in USA and 350% in other parts of the world.
Surgical treatment is classified into three types according to the principle of effect:
1- Mal-absorptive operations: These procedures induce decreased absorption of nutrients by shortening the functional length of the small intestine e.g. jejunoileal bypass and Biliopancreatic diversion (BPD), which has two variants: Scopinaro method and duodenal switch method.
2. Restrictive operations: These procedures reduce the storage capacity of the stomach and as a result early satiety arises, leading to a decreased caloric intake. (e.g., vertical banded gastroplasty (VBG), laparoscopic adjustable gastric banding (LAGB), and sleeve gastrectomy).
3. Combined mal-absorptive and restrictive operations:
e.g.,: gastric bypass.( RYGBP)
Each of these operations has a different amount of typically anticipated weight loss usually expressed as a percentage of the weight above a BMI of 25 lost after surgery or the percentage of excess body weight loss (%EBWL), the impact on obesity-related co-morbidities, and side effects that can affect quality of life. Finally, each procedure requires a motivated individual willing to undergo lifelong follow-up and adherence to lifelong vitamin supplementation regimens.
Roux en-Y gastric by pass has been said to be the ”gold standard” operation for the treatment of morbid obesity. RYGBP has a good long-term weight loss, excellent patient tolerance, and acceptable short- and long-term complication rates. The operation is performed either open or laparoscopic.
The modern RYGBP is the result of several improvements on a gastric bypass operation first developed in 1969 by Dr. Edward E. Mason, in this procedure small intestine is reconfigured into a Y shaped configuration (Roux en Y) consisting of two limbs and a common channel. The proximal small bowel remains attached to the stomach and duodenum below the gastric division. This limb is called (Bilio-pancreatic limb), it drains bile, digestive enzymes, and gastric secretions. The other limb which is the alimentary limb, sometimes called (the Roux limb), is attached to and drains the small proximal gastric pouch, and carries only food. The Roux limb starts where food leaves the gastric pouch and ends where the Bilio-pancreatic limb joins it to form the common channel. At this point the digestive juices and food mix and go on together, passing through the remaining arm of the Y, known as the common channel.
Gastric banding and gastric bypass are the two most prevalent bariatric procedures; gastric bypass procedures increased as a proportion of the total number of procedures over the study period. Gastric banding was the most common operation in patients having primary bariatric surgery. Importantly, gastric bypass has been shown to be superior in terms of percentage postoperative weight loss. Furthermore, patients selected for gastric bypass may have higher body mass index than those selected for banding. This may explain some of the differences in outcome seen between banding and bypass patients. Surgeons became aware early of the disadvantages of banding. Although banding may be technically less challenging to learn and carry out, the increased weight loss seen after bypass may be an additional driver of the increasing preference in Europe for gastric bypass. A recent meta-analysis found that bariatric procedures not only cause significant weight loss but also lead to improvement in many associated conditions such as diabetes, hypertension, hyperlipidemia, and obstructive sleep apnea.
Although gastric bypass surgery has been shown to have a high success rate in terms of sustained weight loss and decreased obesity-related co-morbidities, much complication may occur. Complication may occur in the early period (within 1 month after surgery) e.g.,: leak and bowel obstruction or in the late postoperative time course e.g.,: internal hernia, or nutritional.
The number of gastric bypass procedures has grown significantly from an estimated 14,000 in 1998 to an estimated 108,000 in 2003. The rate of gastric bypass per 100,000 populations grew from 5.3 to 37.1 during the 6-year. period At the same time, the average length of a hospital stay for a gastric bypass discharge decreased 56%, from 7.2 days in 1998 to 3.2 days in 2003.The average length of stay for all patients declined by only 6% during this period, from 5.1 days in 1998 to 4.8 days in 2003. Finally, we found that the complication rate for gastric bypass was similar to the rate for all surgical procedures and lower than the rate for some other abdominal procedures.
A majority of studies reporting RYGBP show superior weight loss results compared to laparoscopic adjustable gastric banding (LAGB). Because the RYGBP is technically demanding, the LAGB technique gained popularity since its introduction in 1986.However, increasing experience with LAGB has shown a high long-term failure rate with severe complication, most of which require reoperation. Indications for conversion to RYGBP are insufficient weight loss (62%). Other reasons concerned complication after LAGB, as food intolerance (11%), pouch dilation (9%), band erosion (6%), necrosis of stomach (4%) and reflux esophagitis (2%).
Although bariatric surgery is the keystone of current therapy of morbid obesity, it has limitations and risks. With regard to endoscopic approaches, for many years intragastric balloons have been the only available treatment option. Preclinical research in the field of therapeutic endoscopy and minimally invasive surgery promises to expand the bariatric surgery. First reports from human studies testify to interesting progress in the development of less invasive approaches. However little is known about these. Several minimally invasive procedures are being tested for feasibility, safety and efficacy, and we review here the development of such procedures in the fields of endoscopy, endoluminal surgery, and natural orifice transluminal endoscopic surgery (NOTES)
Robotic is a recent advance in surgery, particularly in video-assisted mini-invasive surgical procedures requiring manual sutures. Indeed using stitches and manipulating sewing instruments can be greatly facilitated by a robotic system. One of the first promising fields has been heart surgery (coronary bypass). Different procedures have been attempted in laparoscopic abdominal surgery with a robotic system, and recently gastric bypass.