Authors' recommendations: The prevalence of obesity has risen to alarming levels. In Australia, approximately 62% of men and 45% of women are overweight or obese, a situation that places substantial strain to the healthcare system and the economy. Various treatment strategies have been devised and implemented as a means of treating obesity. At first glace, the problem appears to be easy to rectify; reduce caloric intake and increase physical activity. However, medical research has proven that the treatment of obesity, particularly in patients who are morbidly obese and beyond, is not an easy task. Merely 25% of patients are able to maintain lost weight 4-years afters a caloric restriction program, and this is with the caveat that the program is run well enough to attain high participation rates for a minimum of 12 months. Pharmacological interventions although effective to an extent are associated with side effects and the relative effectiveness between these weight-loss drugs is not known (Shekelle et al. 2004). Furthermore, it has been established that dietary, behavioural and pharmacological treatments are not effective for extreme forms of obesity (BMI≥40). The NHMRC and US National Institutes of Health has acknowledged that bariatric surgery is the most effective treatment option for achieving adequate and sustained weight loss in morbidly obese patients. There is no gold standard bariatric procedure at the time of writing, however lap-band is the procedure of choice in Australia; accounting for >90% of cases (O’Brien et al. 2005).A relatively new procedure, sleeve gastrectomy, has recently emerged as a potential alternative to existing techniques. In the strictest sense, SG is technically not a new procedure, it was utilised as a method to resect gastric cancers before being considered as a bariatric procedure. Until recently, it was widely believed that the weight loss than can be achieved with SG is insufficient and therefore it is often performed as part of a multi-stage bariatric procedure (Frezza 2007). SG is often performed laparoscopically and is essentially a partial gastrectomy where the greater curvature of the stomach is removed to reduce the size of the stomach. The resulting decrease in stomach size induces the feeling of satiety sooner with less amount of food; therefore restricting caloric intake and decreasing the patient’s appetite.Randomised trials (Himpens et al. 2006, Langer et al. 2005) and comparative studies (Lee et al. 2007, Cohen et al. [unpublished]) are generally supportive of the effectiveness of SG in inducing superior weight loss compared to lap-band. Both of the included randomised controlled trials highlighted that %EWL was significantly higher for SG patients (Himpens et al. 2006, Langer et al. 2005), and this was sustained up to 3-years post-surgery (Himpens et al. 2006). When SG was compared to duodenal switch and RYGBP, the %EWL achieved was significantly lower (Lee et al. 2007, Hamoui et al. 2006). This was expected considering the fact that duodenal switch and RYGBP are substantially more invasive procedures that employ malabsorptive techniques. However, one study (Vidal et al. 2007) reported that LSG induced similar weight loss to RYGBP. This indicates that SG has the potential to achieve comparable results to RYGBP. None of the studies included presented longer term data which would provide some insight as to whether SG patients eventually attain the similar extent of weight loss as duodenal switch. Despite the fact that weight loss was less impressive relative to duodenal switch and perhaps RYGBP, the results attained with the use of SG is commendable in light of the relative ease and simplicity of the procedure.One of the most interesting aspects of SG is the fact that plasma ghrelin levels decrease significantly following surgery (Langer et al. 2005). Studies have postulated that circulating ghrelin levels decrease with feeding and increase before meals, indicating a role in appetite regulation. A high concentration of ghrelin stimulates hunger and therefore leads to excess consumption of food. Langer et al. (2005) pointed out that the main sources of ghrelin, the gastric fundus and the greater curvature, are completely resected during SG. This therefore explains the significant reduction in ghrelin concentrations compared to lap-band patients where an increase was observed (Langer et al. 2005). It therefore appears that SG is not merely a restrictive procedure, but is augmented by hormonal effects as well. The reduced ghrelin levels may have contributed substantially to the significantly greater weight loss observed in SG patients compared to lap-band patients (Langer et al. 2005, Himpens et al. 2006, Lee et al. 2007, Cohen et al. [unpublished]).The weight loss induced by SG should translate to decreased co-morbidities, as confirmed by Vidal et al. (2007) where 50% patients with type II diabetes experienced complete resolution while 28.6% required less medication at 4-months post-surgery. This was comparable to RYGBP patients, a predictable outcome based on the fact that both patient groups had similar weight loss for this study. One of the factors that may limit the efficacy of SG is the incidence of gastric sleeve dilatation. To date, only one case series study has specifically examined this issue and found that only one patient (3%) experienced sleeve dilatation (Langer et al. 2006). However, further long-term studies with larger patient cohorts are required before a more accurate estimate of the incidence of sleeve dilatation can be determined.As with all bariatric procedures, SG has risks associated with its utilisation; the majority of studies indicate that SG has comparable/lower complication rates relative to lap-band (Himpens et al. 2006, Langer et al. 2005) and substantially safer compared to RYGBP (Lee et al. 2006) and intragastric balloon implantation (Milone et al. 2005). Although complication rates were similar/lower relative to lap-band, the complications experienced by SG patients were more severe (Himpens et al. 2006). Meanwhile, the safety of SG compared to duodenal switch is debatable (Lee et al. 2007, Hamoui et al. 2006). Hospital stay and operating time is comparable to lap-band patients, and is significantly shorter in contrast to RYGBP and duodenal switch (Lee et al. 2007).Overall, the evidence from randomised trials and comparative studies suggest the weight loss achievable with SG is commendable and provides some support with regards to its use as a stand-alone procedure. Its effectiveness in super-obese patients (BMI≥50) compared to established bariatric procedures was not explored in the included studies, but some encouraging evidence exists with regards to its use as a 1st stage procedure prior to more invasive procedures (RYGBP) (Sauerland et al. 2005). It is important to note that the long-term safety and durability of weight loss for SG remains unknown, with one randomised trial demonstrating that SG patients experienced more severe complications (Himpens et al. 2006) and the evidence for the incidence of sleeve dilation is lacking (Langer et al. 2006). Further randomised trials would be required before the efficacy of SG relative to existing bariatric procedures (particularly RYGBP and DS) can be determined. The effects of SG on plasma ghrelin levels and the subsequent effect on appetite warrants further investigation as well.

Project Status: Completed

URL for project: http://www.horizonscanning.gov.au/internet/horizon/publishing.nsf/Content/211ABF81A69CA39DCA2575AD0080F3DC/$File/HS%20Sleeve%20gastrectomy%20as%20a%20single%20stage%20bariatric%20procedure%20OCT%202007.pdf

Year Published: 2007

URL for published report: n/a

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Australia

Organisation Name: Australian Safety and Efficacy Register of New Interventional Procedures-Surgical

Contact Address: ASERNIP-S 24 King William Street, Kent Town SA 5067 Australia Tel: +61 8 8219 0900

Contact Name: racs.asernip@surgeons.org

Contact Email: racs.asernip@surgeons.org

Copyright: Australian Safety and Efficacy Register of New Interventional Procedures - Surgical (ASERNIP-S)