fbpx

Bariatric Surgery: A critical Review of Bariatric surgery on managing weight and obesity

INTRODUCTION

 

Obesity has been described as the greatest threat to human health according to the World Health Organization (WHO). In 2008 1.4 billion adults aged 20 or over were classified as overweight with 500 million of these classified as Obese (WHO, 2008). The WHO classifies Overweight and Obesity as a person having a Body Mass Index (BMI) of 25-29.9kg/m2 for Overweight, a BMI of ≥30kg/m2 for Obese, and a BMI of ≥ 40 or ≥35 for Morbid Obesity if associated with substantial comorbidities. However, a person falling within a BMI range of 18-24.9kg/m2 is classified as normal weight. A recent study carried out in the United States has found that one third of the population has a BMI of ≥30kg/m2  (Wang, Wong, Alfonso-Cristancho, He et al, 2013). It is broadly accepted that the diet industry is a multi-billion dollar business that has played on the vulnerability of overweight and obese people for many years, highlighted by an $18.8 billion in sales in 2003. Indeed, the successful results of these over the counter treatments for obese subjects appear to be limited in the treatment of obesity (Atkinson, blank, Loper et al, 2012). Given the significant increase in obesity and a limited capacity of standard diets to overcome and attenuate obesity and morbid obesity the National Institute of Health established guidelines for surgical procedures for morbid Obesity in 1991.  Subsequently this has led to the growth and development in Bariatric surgery over the past two decades. From its very early days there has been huge success in the results from surgery, leading to improvements and new procedures that are now transforming the lives of those that receive surgery.

 

Obesity is now considered an epidemic that leads to increased morbidity and mortality and reduces the quality of life for its sufferers (Noria et al, 2012). Obesity is linked to many of the chronic illnesses such as diabetes mellitus, coronary heart disease; sleep apnea, osteoarthritis, and many different forms of cancer (Gass, Beglinger, Peterli, 2011).  It is now estimated that a BMI as low as 21 could influence the chance of contracting any one of these illnesses (Noria, Grantcharov, 2012). Given the associations of obesity with various diseases, Bariatric surgery is an active area of research that has developed dramatically over the last thirty years as Obesity and super Obesity continues to increase. The results from these surgeries have provided the best long-term health benefits for obese patients who have not responded to traditional approaches to weight loss (Brzozowska, Sainsbury, Eisman, Baldock, Center, 2013). Bariatric surgery as an intervention that has become more popular as patients see the surgery as a solution to reducing their BMI and weight associated illnesses (Wang et al, 2013). In 1998 40,000 bariatric surgeries were carried out worldwide, whilst in2008 this figure increased to 345,000 (Schigt et al, 2013). Similarly, there were 20,000 bariatric surgeries carried out in the US in 1999, however, in 2004 over 144,000 patients had undergone bariatric surgery.

 

 

 

HISTORY AND DEVELOPMENT OF BARIATRIC SURGERY

 

Bariatric surgery procedures have been performed using different techniques since the 1950s.The treatment of Obesity using surgery was investigated by Kremen, who performed an end-to-end jejunoileal bypass for the reduction of bodyweight. This procedure was later standardized by Payne and De Wind where an end to side jejunoileostomy procedure where the proximal 35cm of the jejunum were anastomised to the distal ileum 10cm proximal to the ileocecal valve. It was not until Buchwald and Varco modified the procedure in 1971 that results were really identified (Gass et al, 2011). They modified previous procedures and anastomosed 40cm of the jejunum to the distal ileum, 4cm prior to ileocecal valve, resulting in dramatic decreases of 90% in cholesterol and a 96% reduction in triglycerides (Gass et al, 2011). Due to severe side effects and adverse outcomes, most surgeons abandoned the procedure after a review by Hocking et al in 1983 highlighted these adverse side effects (Miller, Choban, 2013).

 

Mason developed restrictive surgical procedures, such as the Verical Banded Gastroplasty in 1980. This procedure became the most popular technique in the 1980’s. (Pardela, Wiewiora, Sitkiewicz, Wylezol, 2005). It allowed for the patient to decrease the amount of swallowed food as the stomach was divided into two, a small pouch with a volume of 25-50ml was attached to the remaining stomach through a narrow channel only 12mm wide. A mesh band was wrapped around the curvature of the channel, and the stomach was stapled to reduce size. The results of this technique were not very successful with only 38% of patients losing 50% of their weight over 3 years (Pardella et al, 2005). Surgeries kept developing, but not without risks such as dumping syndrome, micronutrient deficiencies, and the loss of therapeutic endoscopic procedures in the distal stomach, duodenum, and bile duct system (Gass et al, 2011). The first Adjustable Gastric Band (AGB), was introduced in 1986 by Kuzmak, from a combination of previous gastroplasty variants and banding procedure where the band was fixed in the upper part of the stomach, dividing the stomach into two parts (Pardella et al, 2005). This silicon band had an inflatable balloon at the inner surface connected with a port placed subcutaneously, through which the size of the stoma can be adjusted by adding or subtracting fluid. By 1993, Laparoscopic adjustable gastric band (AGB) was very popular (pardella et al, 2005).

 

Bariatric surgery was to develop even further with the development of Roux-en-Y gastrojejunostomy (RYGB). RYGB is considered the gold standard in bariatric surgery with excellent results in both weight loss and quality of life (Vasas, Dillmans,  Van Cauwenberge, De Visschere, Vercauteren, 2013) This operation can be performed laparoscopically with an open incision and is the most common type of surgery for weight loss (Miller et al, 2013).  This surgery involves a small stomach pouch being separated from the stomach and attached to the small intestine through a hole only 10mm in diameter. This excludes the distal part of the stomach, duodenum and the first 50cm of the jejunum (pardella et al, 2005).  The Roux limb is created by dividing the jejunum from 30 to 150cm distal to the ligament of the treitz and by bringing the divided end up to the gastric pouch. This is usually 100 to 150 cm in length and is determined by jejunostomy’s location and ability to re-establish bowel continuity. This restriction, normally about 15mm long, results in the slow emptying of the pouch (Miller et al, 2013).  The size of the pouch will restrict the volume of the ingested food, as 95% of the stomach is by-passed.

 

Biliopancreatic diversion (BPD) was developed in the late 1970’s by Scopinaro and consisted of 200-500ml gastric pouch formed by a horizontal distal gastrectomy that allows patients eat large amounts of protein. This procedure was done by using the Roux-en-Y procedure with alimentary limb of 250cm of ileum including a common limb of 50 cm. The duodenum and jejunum are bypassed and bring the biliopancreatic juices to the common channel. This leads to the malabsorption not only of micronutrients but also macronutrients such as fats, carbohydrates and proteins (Gass et al, 2011). BPD was developed further Marceau during the 1990s. This involved a sleeved stomach with verical resection of the main part of gastric fundus and corpus with preservation of the innervations at the lesser curvature and preservation of pylorus. The distal ileum was connected to the proximinal duodenum with the goal of reducing side effects (Gass et al, 2011). This procedure affects absorption by decreasing the time that the digestive enzymes can interact with food, by increasing the transit time for food and the absorptive surface area (Miller et al, 2013)

 

Even though Bariatric surgery has been around for many years, there have not been many longitudal studies carried out. Possibly the most conclusive study is the Swedish Obesity Study (SOS)(L. Sjostrom, 2012). This is an ongoing study that is investigating the long-term effects of Bariatric surgery on obese subjects. The investigators recruited 2010 obese subjects whose surgeries ranged from gastric bypass (13%), Banding (19%), to vertical banded gastroplasty (68%). The control group consisted of 2037 subjects who received usual care. The mean BMI of men was ≥34kgm-2 and ≥38kgm-2 for women for inclusion into the study. The investigators so far have found that mortally rates were reduced by 30% as 101 subjects died in the surgery group compared to 129 in the control group (L. Sjostrom, 2012). It was demonstrated that bariatric surgery was associated with a reduced incidence of cardiovascular deaths and a reduction in cardiovascular events. Interestingly, Sjostrom (2012) found that the number of women after inclusion with first time cancers was lower in the surgical group compared to the control group, however, there was no effect of surgery on cancer in men. Subsequently, the investigators  concluded that benefits of weight loss on cancer is greater in women than in men. From the Swedish study we can see that over a long period of time the benefits of bariatric surgery are beneficial not only the improvement in quality of life, but also increases the lifespan of obese subjects.

 

 

 

 

BENEFITS OF BARIATRIC SURGERY

 

The current surgical procedures have seen patients achieve results and lifestyles that they would never have achieved from non-surgical interventions. Achieving weight loss has been proven to increase the improvement of intermediate risk factors for disease (L.Sjostrom, 2012).  Bariatric surgery has been shown to reduce cardiovascular disease, diabetes, biliary disease, health related quality of life, and Obstructive Sleep Apnea (L.Sjostrom, 2012). As surgeons develop and improve the surgical techniques of Bariatric operations they are becoming safer with much lower rates of mortality compare to when the surgery was first introduced. From 1998 to 2004 the mortality rate fell by 78% from .89% to .19% (Miller et al, 2013).

 

This continued weight reduction can have many positive effects on the quality of life that the patient may achieve if they manage to keep their weight under control. Activities undertaken by normal and even overweight persons can be hindered by severe obesity. Tasks such as personal hygiene, walking and loss of autonomy are problems that severe obese individuals may suffer from (Neff, Olbers, Le Roux, 2013). By reducing patients BMI they will see an immediate impact on mobility and physical activity. Many patients will be able to partake in simple everyday tasks that were previously impossible to perform. The reduction in weight also leads to a reduction in joint and back pain.  Results from the Swedish Obesity study found that obese women post bariatric surgery had lower work related restrictions pain in both the knee and ankle joints. The study also found a higher recovery rate from baseline for back, neck ankle and knee pain for subjects after bariatric surgery compared to subjects treated by conventional methods (L.Sjostrom, 2012). Many obese subjects have reported an increase in mobility and less joint pain post operation.

 

 

While the results of different surgeries may differ, the majority of postoperative Bariatric patients manage to sustain >50% of the weight loss for many decades (Miller, 2011). Patients generally lose up to 35% of their initial weight, which is equivalent to a loss of 62-75% of excess body weight with RYGB. This procedure would appear to give patients the greatest weight loss, however, the other procedures also produced results above 40% for excess body weight reduction (J. Devereaux, 2013). By reducing body weight by these percentages has a huge impact on subjects that suffer from metabolic syndrome, as weight reduction can improve all features of metabolic syndrome.  Subjects with metabolic syndrome have a 1.5 to 3% chance of developing coronary heart disease and are at higher risk of suffering from a stroke (Klein, 2004). Of the two most popular surgeries carried out in Europe, LRYGB showed an excess weight loss 26% higher than LAGB. LAGB also saw weight regain which led some subjects to require a second bariatric procedure (Schigdt et al, 2013) got to here

 

 

Data compiles over the last 20 years has associated the reduction on cardiovascular mortality and morbidity with bariatric surgery (Neff et al, 2013). While the mechanisms are unclear as to why we see a reduction, it is believed that improved blood lipids profiles, reduced hypertension and improved glucose metabolism may be the contributing factors (Neff et al, 2013). This is a result of the difficulty in prolonged bouts of weight loss >5 years with non-surgical methods (Klein et al, 2004). Weight loss following bariatric surgery results in a decrease in both diastolic and systolic blood pressure (Klein et al, 2004). Hypertension post operation was resolved in 61.7% and resolved or improved in more than 78% of post-operative patients (Buchwald, Avidor, Braunwald et al, 2004). Depending on the type of surgery the subject has will impact on the weight loss results of the patient. Patients in the Swedish Obesity Study who underwent surgery saw blood pressure begin to rise after two years post surgery. These patients underwent gastric banding or vertical banded gastroplasty and lost less weight than those that received the gastric bypass surgery. These subjects maintained lower blood pressure for five years post operation (Klein et al, 2004). The longer a subject is exposed to obesity, the worse the cardiac function and a larger ventricular mass will become. Obesity is strongly associated with Cardiomyopathy with left ventricular hypertrophy and diastolic dysfunction. Results from Bariatric surgery has shown to improve cardiac function and reverse modelling of the left ventrical up to three years post operatively (Neff et al, 2013).

 

 

Type 2 Diabetes has been strongly associated with Obesity with over 50% of those diagnosed with diabetes also classified as obese. Bariatric surgery has been reported to induce remission of diabetes with the weight lost by patient. The Swedish Obesity Study reported on the impact of surgery on the reduction of type 2 Diabetes (T2D). The investigators reported 72% of the surgery group were in remission at 2 years, and new incidence of T2D was reduced by 96% (2 years), 84% (10 years), and 78% (15 years) in subjects that had no diabetes at baseline (L. Sjostrom, 2012).

 

 

Obesity is also strongly associated with Obstructive Sleep Apnea (OSA). This form of sleep apnea consists of repetitive obstruction of the upper airway during sleep in which ineffective respiratory efforts occur (Noria et al, 2013). Bariatric surgery may improve the severity of sleep apnea as reported in the Swedish Obesity survey where the investigators reported a reduction in sleep apnea from 23% at baseline to 8% after year two of the study for subjects in the surgical group. However, the investigators reported that showed a reduction from 22% at baseline to 20% after year two for the control group. The investigators did not classify the severity of sleep apnea that the patients were suffering from. Bariatric surgery has been strongly associated with the reduction, but not the total remission of sleep apnea. Depending on the severity of sleep apnea that the patient suffers from, the results may vary. Surgery may leave the patient suffering less sleep apnea, but still in a moderate to severe category (Neff et al, 2013). Obese patients that are older and heavier may still suffer from OSA while they think that they are cured due to increased mobility and agility as a result of surgery (Noria et al, 2013)

 

Polycystic Ovarian Syndrome (POS) is strongly associated with insulin resistance in obese women (Miller et al, 2011). Many obese women use the chance of becoming pregnant as a motivational tool for receiving bariatric surgery (Miller et al, 2011). By reducing weight, regular menstrual cycles from enhanced insulin sensitivity, improved hirsutism and reduced hperandrogenaemia, all lead to increased fertility in sufferers of POS (Kyriacou, Hunter, Tolofari, Syed, 2013). Clinical guidelines suggest that patients should not become pregnant within the first 18 months of receiving the surgery as patients tend not to be able to ingest the correct amount of protein (1.2g/kg ideal body weight per day) and that vitamin and mineral stores are in the normal range.

 

Cost of Obesity can be felt directly and indirectly in society. While bariatric surgery is expensive in the short term, the return in the long term is great not only for the individual, but for society as a whole. There is a cost to obesity, not only to the individual but also to the economy. It is estimated that Obesity related diseases cost to world healthcare between 2% and 7% of total healthcare costs (F. Azizi, 2013). These costs are linked to obesity related diseases such as type 2 diabetes, cardiovascular disease, prescriptions  which can be double that what a normal weight person would require (Schigt et al, 2013). In the USA 2003 it was reported that medical costs in excess of $75 million were attributed to Obesity and Obesity related diseases (Wang et al, 2011). Obese individuals are more than twice as likely to take sick days and three times as likely to avail of disability benefits (Neff et al, 2013). Finkelstein, Fiebelkorn and Wang (2003) reported that Obese patients incur more than 46% of impatient care, 27% of physician visits and outpatient costs, and 80% increased spending on prescription drugs.

 

It is easy to put a price on obesity for society, but obese individuals who avail of surgery will see a dramatic improvement in their lives. The cost effectiveness of surgical procedures was between $6,200 to $17,300 per quality-adjusted life expectancy years (QALYs), which depends on the type of operation performed (Wang et al, 2012). QALYs is defined as incorporating both quality and length of life, this borne out the comparison between the cost of bariatric surgery and ordinary treatment and the difference in effectiveness of the two treatments (Maklin, Malmivaara, Linna et al, 2011). From the rise in Obesity and the pressure that it is now putting on healthcare systems across the world, the more surgeries and the more developments in bariatric surgery will help to reduce the burden on national healthcare systems. In 2008, obese patients cost the US healthcare system 10% of the total healthcare budget, coming in at $147 billion (M. Effrat and R. Effrat, 2012). Jacoby (2008) argues that if we can treat the illnesses associated with obesity at an early stage then there can be a positive outcome on health, and reduce the cost on the health service. WHO have estimated that cost/kg of weight lost from surgical treatment after four years is less expensive than any other treatment (Schight, 2013). Maklin et al (2011) reported that bariatric surgery was an effective method in reducing the burden of obesity on the Finnish healthcare system. The investigators reported the cost of obesity is around €260 million where €190 million is directly related to the healthcare system. They found that surgery was more effective than other treatments with patients receiving ordinary care receiving 1.5 times more treatments than subjects who had bariatric surgery.

 

RISKS OF BARIATRIC SURGERY

 

Given that Bariatric surgery is a very invasive surgery, it has become a very safe procedure considering the size of the patient and the seriousness of the comorbidities (Pories et al, 2008). As the surgeries develop and new techniques are explored, different forms of bariatric surgery become popular. Currenty, RYGB surgeries are favoured in Europe, with the rise in Laparoscopic Roux-en-Y gastric bypass surgery considered more a safer treatment than RYGB, even though it is a more technically challenging procedure  (Lee, Yu, Wang et al, 2005).

In 1991, mortality rates for bariatric surgery ranged from .5% to 1.5% (Benotti et al, 2013). Mortality rates from Bariatric surgery now range from 0.09% to 0.3% for 30-day mortality after surgery. Laparoscopic surgery is 0.07% compared to 0.3% for open procedures (Schigt et al, 2013). However, while the surgery itself is relatively safe, complications after surgery can be deadly if not treated by surgeons familiar with them in a prompt manner. While these figures are encouraging, patients with higher BMI levels have been reported to have less favourable outcomes (Benotti, Wood, Winegar et al, 2013). Such complications include haemorrhage, obstruction, anastomotic leaks, infection, arrhythmias, and pulmonary amboli (W.A. Pories, 2008). These complications and mortality rates that were presented by surgical centres, led to the development of a validated risk scores for RYGB procedures. The aim was to define overall 30-day mortality rates in current bariatric surgery practice and create a simple scoring system to predict these mortality rates (Benotti et al, 2013). However, there are complications that will present themselves in the years after surgery include nutritional deficiencies, internal hernias, and emotional disorders (W.A. Pories et al, 2008).

 

One risk of Bariatric surgery is the patient will have invasive surgery and not get the required weight loss from the surgery. This tends to lead the surgeon to perform a revisional surgery on the patient (Vasas et al, 2013). Vasas et al (2013) reported of cases where reviosonal surgery being carried out on patients that previously had a VGB surgical procedure, then having to RYGB procedure carried out some time later. These were patients that presented for severe gastrointestinal problems due to kinking at the level of the initial ring or mesh and/or to progressive stenosis. Patients also presented with maladaptive eating, which resulted in weight gain. The results according to the investigators were favourable with significant weight reduction and reversal of symptoms following the surgery.

 

 

 

CONCLUSION

 

With over 500 million adults obese across the world (WHO, 2008), it is important that solutions are found to improve not only their quality of life, but also the economic burden they place on health systems and the economy as a whole. Bariatric surgery is a very effective treatment for obesity with few complications when performed by surgeons with plenty of experience (Schigt et al, 2013). As surgeons investigate new safer and less invasive surgeries and improve operating standards, the impact on the patient has become less traumatic with better outcomes and less cost. The benefit to the individual and to society from receiving surgery is immense. By making bariatric surgery more available to the wider obese population, there is a chance to reduce healthcare costs and to improve the quality of life of the individual. It is only recently that we are seeing the benefits of bariatric surgery with the publishing of longitudal studies such as he Swedish Obesity study. These studies highlight how effective over a longer period of time bariatric surgery is. It also gives a good insight into which surgeries are most effective and cost efficient for patient and payee. As surgical techniques and procedures improve the safety and efficiency of the surgery also improve.

 

The importance of improving the quality of life for obese subjects should not be undervalued. It is important that they receive the same medical care that subjects suffering from other diseases receive. While the perception of obesity is that of mockery in some quarters of society, it is important from a medical perspective that improvements are constantly developed in both surgery and after care. We can see some of the conditions associated with obesity either reduce or remit completely after surgery. While the surgeries on offer are not yet perfect, they have certainly improved the lives of those that have received them. The surgeries have also led to reduction in costs to healthcare, as the patient becomes more self reliant and less reliant on the healthcare system to treat different illnesses associated with obesity.  Bariatric surgery can be viewed as a powerful treatment in the fight against the obesity epidemic (Noria, et al, 2013).

 

 

 

 

 

 

 

REFERENCES:

Akinson, R.L., Blank, R.C., Loper, J.F., Schumacher, D., Lutes, R.A. (2012). Combined drug treatment of Obesity. Obesity Research 3 (4), 497s-500s.

Azizi, F. (2013). Bariatric Surgery for Obesity and and Diabetes. Archives of Iranian Medicine 16 (3), 182-186.

Benotti, P., Wood, G.C., Winegar, D.A., Petrick, A.T., Still, C.D., Argyropoulos, G., & Gerhard, G.S. 2013. Risk factors Associated with Mortality After  Rouex-en-Y Gastric Bypass Surgery. Annals of surgery 00 (00), 1-8.

Brzozowska, M.M., Sainsbury, A., Eisman, J.A., Baldock, P.A., & Center, J.R. (2013). Bariatric Surgery, bone loss, obesity, and possible mechanisms. Obesity reviews 14, 52-67.

Buchwald, H., Avidor, Y., Braunwald, E., Jensen, M.D., Pories, W., Fahrbach, K., & Schoelles, K. (2004). Bariatric Surgery a Systematic Review  and Meta-analysis. Journal of American Medical Association 292, 1724-1737.

Devereaux, J. (2012). Making the healthy choice the easy choice. Childhood obesity 8 (1), 82-84.

Efrat, M.W., Efrat, R. (2012). Tax policy and the Obesity epidemic. Unpublished.

Finklestein, E.A. fiebelkorn, & I.C., Wang, G. (2003). National medical spending attributable to overweight and obesity: how much and who’s paying? Helath Affairs – Web Exclusive, W (3), 219-226.

Gass, M., Beglinger, & P.Peterli. (2011). Metabolic sugery – principles and current concepts. Langenbeck’s Archives of Surgery 396 (7), 949-972.

http://www.who.int/mediacentre/factsheets/fs311/en/

Jacoby, E. (2004). The obesity epidemic in the Americas: making healthy choices the easiest choices. Revista Panamericana de Salud Publica, 15 (4), 1-7.

Klein, S., Burke, L.E., Bray, G.A., Blair, S., Allison, D.B., Pi-Sunyer, X., Hong, Y., & Eckel, H. (2004). Clinical Implications of Obesity With Specific Focus on Cardiovascular Disease: A Statement for Professionals From the American Heart Association Council on Nutrition, Physical Activity, and Metabolism: Endorsed by the American College of Cardiology Foundation. Circulation 110, 2592-2967.

 

Kyriacou, A., Hunter, L., tolofari, S., & Syed, A. (2013). Effectiveness of bariatric surgery on women with and without polycystic overarian syndrome. Endocrine Abstracts 31, 214.

Lee, W.J., Yu, P.J., Wang, W., Chen, T.C., Wei, P.L., & Huang, M.T. (2005). Laparascopic Roux-en-Y Versus Mini Gastric Bypass for the treatment of Morbid Obesity A Prospective Randomiized Controlled Clinical Trial. Annala of Sugery 242 (1), 20-28.

Maklin, S, Malmivaara, A., Linna, M., Victorzon, M., Koivukangas, V., Sintonen, & H. (2011). Cost-utility of bariatric surgery for morbid obese in Finland. British Journal of Surgery 98, 1422-1429.

Miller, M.R., & Choban, P.S. (2013). Surgical Management of Obesity: Current State of Proceedure Evolution and Strategies to Optimize Outcomes. Nutrition in Clinical Practice 26 (5), 526-533.

Neff, K.J., Olbers, & T., Le Roux, C.W. (2013). Bariatric surgery: the challenges with candidate selection, individualizing treatment and clinical outcomes. BMC Medical 11(8), 1741-7015.

Noria, S.F., & Grantcharov, T. (2012). Biological effects of bariatric surgery on obesity-related comorbidities. Canadian Journal of Surgery 56 (1), 47-57.

Pardela, M., Wiewiora, T., Sitkiewicz, & M., Wylezol, M. (2005). Journal of Physioloogy and Pharmacology 56 (6), 33-44.

Pories, W.A. (2008). Bariatric Surgery: Risks and Rewards. The Journal of Clinical Endocrinology & Metabolism 93 (1), 89-96.

Schigt, A., Gerdes, V.E.A., Cense, H.A., Berends, F.J., Van Dielen, F.M.H., Janssen, I, Van der Laar, A., Van Wagensveld, B.A., Romijn, J.A., & Serlie, M.J. The Netherlands Journal of Medicine 71(1), 4-9.

Sjostrotrom, L. (2012). Review of the key results from the Swedish Obese Subjects (SOS) trial – a progressive controlled intervention study of bariatric surgery. Journal of Internal Medicine 273, 219-234.

Vasas, P., Dillmans, B., Van Cauwenberge, S., De Visschere, M., & Vercauteren, C. (2013). Short- and Long-Term Outcomes of Vertical Banded Gastroplasty Converted to Roux-en-Y Gastric Bypass. Obesity Surgery 23, 241-248

Wang, B.C.M., Wong, E.S., Alfonso-Cristancho, H.E., Flum, D.R., Arterburn, D.E., Garrison, L.P., & Sullivan, S.D. (2013). Cost Effectiveness of bariatric surgical procedures for the treatment of severe obesity. European Journal of Health Economics DOI 10.1007/s10198-013-0472-5

About the Author admin

Leave a Comment: