Negative effects of bariatric surgery
Overall, bariatric surgery is remarkably safe. Mortality rates for bariatric procedures in expert centres are comparable with those for other common operations such as laparoscopic cholecystectomy. Nonetheless, complications can be lethal and require prompt treatment by clinicians who are familiar with the procedure and its potential adverse outcomes.
Inclusion criteria for bariatric surgery emphasise the importance of a patient’s comprehension of the risks and consequences of the operation as well as the necessary preparation for surgery. Patients are often required to follow a very low energy diet for at least two weeks preoperatively to minimise hepatomegaly, which can make surgery more technically difficult. Patients taking antihypertensive or glucose lowering medication need close supervision during this period. Smoking and alcohol excess are also generally viewed as contraindications to bariatric surgery.29 After the surgery and acute recovery stage, mandatory long-term multidisciplinary input requires motivation and compliance from the patient.
Acute complications can occur in 5 to 10% of patients, depending on the operation. Many complications are similar to those that arise after other abdominal surgeries, such as haemorrhage, obstruction, anastomotic leaks, infection, arrhythmia and pulmonary emboli.29
Complications following LAGB include enlargement of the proximal gastric pouch (regurgitation, heartburn), band slippage leading to obstruction (vomiting, dysphagia) and band erosion through the stomach wall (epigastric pain, bleeding, infection). Revision is required in 1 to 2% of cases each year; most complications can be managed through band adjustments and appropriate dietary advice.30 LSG can result in leaks at the staple line, haemorrhage or gastro-oesophageal reflux. Severe gastro-oesophageal reflux is therefore viewed as a contraindication to LSG. RYGB can be complicated by acute anastomotic leaks (1 to 3%) or ulcers, internal hernias or strictures leading to obstruction.30 Strictures may manifest as frequent vomiting and usually mandate prompt investigation and surgical assessment.
Chronic surgical complications
Six percent of operations reported to the Australian Bariatric Surgery Registry in 2019 were revisional. In the SOS cohort, after a mean follow up of 19 years 27.8% of the cohort underwent first time revisional surgery, which included conversions to RYGB, corrective surgery and reversal of the surgery to normal anatomy. LAGB was associated with the highest rate of revisional surgery at 40.7% compared with only 7.5% of those who had RYGB.31 Anastomotic ulceration may occur following RYGB with an incidence of 11.4% reported at eight years after surgery. Renal failure and cigarette smoking were the strongest risk factors for this complication in a large US study.32
In a recent study from Western Australia in which Health Data Linkage was used to assess the 24,766 patients who underwent bariatric surgery between 2007 and 2016, 20.2% required at least one bariatric reoperation. Surgical complications were the main indication for reoperation in 67.4% and weight-related in the remainder. Of those who had a single reoperation, the five-yearly rate of having a second revision was 58.2%, a third 38.3% and a fourth revision 45.2%. Patients who had a LAGB were more likely to need an initial revisional operation and those who had revisional surgery had a higher rate of endoscopic procedures and body contouring postoperatively.33