Design of the Verbiest trial: cost-effectiveness of surgery versus prolonged conservative treatment in patients with lumbar stenosis

BACKGROUND: Degenerative changes of lumbar spine anatomy resulting in the encroachment of neural structures are often regarded progressive, ultimately necessitating decompressive surgery. However the natural course is not necessarily progressive and the efficacy of a variety of nonsurgical interventions has also been described. At present there is insufficient data to compare surgical and nonsurgical interventions in terms of their relative benefit and safety. Previous attempts failed to provide clear clinical recommendations or to distinguish subgroups that substantially benefit from a certain treatment strategy. We present the design of a randomized controlled trial on (cost-) effectiveness of surgical decompression versus prolonged conservative treatment in patients with neurogenic intermittent claudication caused by lumbar stenosis. METHODS/DESIGN: The aim of the Verbiest trial is to evaluate the effectiveness of prolonged conservative treatment compared to decompressive surgery. The study is a multi-center randomized controlled trial with two parallel groups design. Patients (age over 50) presenting to the neurologist or neurosurgeon with at least 3 months complaints of neurogenic intermittent claudication and considering surgical treatment are eligible for inclusion. Participants are randomly allocated to either prolonged conservative treatment, receiving further treatment from their general practitioner and physical therapist, or allocated to surgery and operated within 4 weeks. Primary outcome measure is the functional assessment of the patient as measured by the Zurich Claudication Questionnaire at 24 months of follow-up. Data is analyzed according to the intention to treat principle. DISCUSSION: With a cost-effectiveness analysis the trade off between the costs of prolonged conservative treatment and delayed surgery in a smaller number of patients are compared with the current policy of surgical management. As surgery is expected to be inevitable in certain subgroups of patients, the distinction of and classification by predictive patient characteristics is most relevant to clinical practice. TRIAL REGISTRATION: Netherlands Trial Register (NTR): NTR2216