A multidisciplinary team of researchers, including rheumatologist Rachelle Buchbinder from the Cabrini Institute, Melbourne, are undertaking the first randomised placebo-controlled trial of decompressive surgery for symptomatic central lumbar spinal stenosis that they say will address the shortfalls of previous surgical trials.

Current management of central lumbar spinal stenosis (LSS) includes surgery to decompress the spinal canal and alleviate symptoms but the evidence supporting the procedure is currently ‘inconclusive’, the researchers said in their study protocol published in BMJ Open.

The SUrgery for Spinal Stenosis (SUcceSS) trial will evaluate the efficacy, safety and cost-effectiveness of decompressive surgery for people with severe LSS who have failed to respond to non-operative care.

Outcomes to be evaluated include disability, walking capacity, pain, quality of life, serious adverse events and reoperation rates.

“Our study hypothesis is that decompression surgery is more effective, more cost-effective and safer than placebo surgical intervention in improving pain and function in patients with LSS,” the research team wrote.

The trial will also involve a parallel observational study of eligible participants who decline to be randomised to the placebo-controlled trial to test for any selection bias.

The research team noted the ongoing debate around whether the comparator for surgical treatment should be placebo or sham.

They opted for placebo surgical intervention because it was associated with larger beneficial effects on the participant than a sham and allowed for more reliable blinding of patients and assessors, than any other comparator.

“In the case of lumbar surgical decompression, this means that the placebo surgical intervention must include muscle dissection down to the bone of the lumbar lamina, but no removal of bone or ligamentum flavum,” they wrote.

“The inclusion of a placebo surgical intervention will ensure blinding of participants and assessors to treatment allocation, limiting treatment crossover and account for any placebo effect associated with decompression surgery.”

As a result, the study will provide high-quality evidence for the efficacy of decompressive surgery in treating LSS, they concluded.