Long Term Effect of Sleeve Gastrectomy on Weight Loss and Ghrelin
Sleeve gastrectomy is a bariatric procedure that has become vastly popular due to its great efficacy for weight loss. It is performed either as a sole operation in morbidly obese people or as a first step in super-obese patients, followed by a second intervention, which is usually Roux-en-Y gastric bypass (RYGB) or bilio-pancreatic diversion with duodenal switch (BPDDS).
Sleeve gastrectomy (also called vertical sleeve gastrectomy) involves removing about 85% of the stomach thus restricting the amount of food that can be eaten. Unlike gastric bypass, sleeve gastrectomy procedure leaves the intestines intact. It is therefore a purely restrictive procedure. No gastrointestinal malabsorption occurs since the intestines are not bypassed. Although it is less invasive than gastric bypass, recent studies show that it has similar short and intermediate-term results with gastric bypass.
A 2010 study by Dr Arthur Bohdjalian published in the peer-reviewed journal Obesity Surgery followed for 5 years after the surgery 26 patients who underwent Sleeve Gastrectomy at the Medical University in Vienna. Before the surgery, patients had a mean weight of 134.5 kg (296 lb) and an average BMI (Body Mass Index) of 48.2 kg/m2. The majority of patients had not had bariatric surgery ever before.
Weight Loss After Sleeve Gastrectomy
Within the first year patients lost most of the weight. Specifically, they lost 57.5% of their excess weight. During the second year the patients' mean weight continued to decrease and by the end of the second year the mean excess weight loss was 60.3%. By the end of the fifth year, patients were carrying 45% of their pre-surgery excess weight.
Weight Regain After Sleeve Gastrectomy
Weight regain after weight loss surgery is a common phenomenon. In this study, almost 1 out of 5 of patients showed weight regain of more than 10 kg (22 lb) following SG. Those who regained some weight started getting it back one year after the surgery. This resulted in 15% of the SG patients having to convert SG to gastric bypass due to weight regain or reflux.
Sleeve Gastrectomy and Reflux
Gastroesophageal reflux disease (GERD), also known as acid reflux, appears in some patients as soon as they indergo sleeve gastrectomy. The symptoms of this disease are caused by the liquid content of the stomach which regurgitates into the esophagus. The regurgitated liquid which contains acid and pepsin that are produced by the stomach, inflames and damages the lining of the esophagus. Bohdjalian reports in his study that patients received pantoprazole and omeprazole to counteract the acidity caused by the reflux.
Sleeve Gastrectomy and Ghrelin - How Does SG Cause Weight Loss?
Ghrelin is a hormone produced by the parietal cells in the stomach. Higher ghrelin levels are associated with increased hunger and higher food consumption. The levels of ghrelin change depending on the type of weight loss surgery. For example, one study found that plasma ghrelin levels are down-regulated with laparoscopic SG operation but up-regulated with laparoscopic adjustable gastric banding (LAGB) operation.
In this study, SG resulted in reduction of plasma ghrelin levels, which remained at low levels throughout the entire 5-year follow-up. The reduction of ghrelin after SG is expected because the ghrelin-producing tissue in the stomach is almost completely removed in SG. As Bohdjalian explains, this decrease in ghrelin levels may be the reason for the excellent weight loss success after SG.
Although a small percentage of patiets who undergo SG may need re-operation due to inadequate weight loss - a possible reason for that being gastric dilation - SG is considered equal to LAGB, RYGB and BPD in terms of popularity and efficacy of weight loss. SG is no longer reserved for only the high-risk patients as it used to. Being a strictly restrictive proceduire, SG has a great advantage over the more invasive and malabsorptive procedures: It is less likely that it will lead to vitamin and mineral deficiencies which are common to bypass procedures such as RYGB and BPD.