Failed dietary and lifestyle management is the impetus for surgical referral. It is accepted that three to six months of lifestyle change be trialled before putting patients forward as candidates for surgical management. During this time, the patient’s level of motivation to adopt major lifestyle changes can be assessed. A realistic and sustainable diet plan should be implemented rather than a ‘fad’ diet. Pharmacotherapy adjuncts should be used, taking into consideration other obesity comorbidities and intercurrent health management issues.
Patients may seek advice from their GP regarding suitability, operation selection and risk of complications. They have often discussed the procedure with others who have undergone weight loss surgery and many have also performed online research. Patients need to be made aware that there is not yet medium or long-term evidence to support some novel techniques such as some endoscopic procedures. An outline of the different operations available should be given to patients, with a discussion of the risks, potential complications and expected benefits. Patients should also be informed of the necessary postoperative diet and lifestyle changes. Patient discussions with a bariatric surgeon will provide more detailed information regarding operative issues.
A preoperative upper gastrointestinal endoscopy is performed, preferably by the surgeon, primarily to identify a hiatus hernia requiring repair at the time of bariatric surgery, to reduce the risk of postoperative gastro-oesophageal reflux disease. Endoscopy will also detect Barrett’s oesophagus, which is a relative contraindication to some operations. Preoperative assessment by the anaesthetist may require specific cardiac or respiratory tests.
Surgical options and current trends
In 2014-15, an estimated 22,700 weight loss surgical procedures were performed in Australia, an increase from 9300 in 2005-06 according to an Australian Institute of Health and Welfare report.19 More than 90% were performed in the private sector, highlighting the lack of government recognition for access in the public sector. Robotic bariatric surgery is reportedly equivalent but not superior to other types of minimally invasive bariatric surgery, although surgeons report benefits with regard to improved image quality and suturing.20
Biliopancreatic diversion with duodenal switch is not discussed in this article as the procedure is infrequently performed in Australia. However, there is increasing interest in this operation as it provides the greatest weight loss and improvement in comorbid conditions.21
Sleeve gastrectomy is usually performed laparoscopically. In most patients, 70 to 80% of the stomach is removed by stapling parallel to the lesser curvature in a cephalad direction (Figure 1a). The pylorus is preserved, which reduces the risk and severity of dumping syndrome. As well as greatly reducing the gastric volume, sleeve gastrectomy only leads to several metabolic and hormonal changes. These include reduced levels of ghrelin (the hunger peptide), glucagon, glucagon-like peptide 1 and leptin.22 Initial weight loss is swift and sustained, with only minor weight gain after several years in most patients.23 The major complications of sleeve gastrectomy are staple line leak or bleed in the immediate postoperative period and gastro-oesophageal reflux as a later problem.
Sleeve gastrectomy has become the dominant operation type in most industrialised countries including Australia.24 The reason is that it is more reliably effective than gastric band surgery, which was previously the most frequently performed operation but is now far less commonly performed. Sleeve gastrectomy has very similar effectiveness to Roux-en-Y gastric bypass (RYGB), with both operations providing more than 70% excess weight loss in a randomised trial.23 It is, however, significantly safer than the RYGB operation and avoids the long-term complications of the bypass operation.24,25