Long-term efficacy of percutaneous epidural neurolysis of adhesions in chronic lumbar radicular pain: 10 year follow-up of a randomized controlled trial

Background: No long-term follow-up data exist in any treatment for chronic radicular pain occurring with disc pathology and after failed back surgery. A previous randomized controlled trial (RCT) has proven efficacy in short-term follow-up as an evidence-based effective therapeutic option. Objectives: Long term data is needed to determine the efficacy and cost-effectiveness of minimal invasive procedures. The present study reports 10 year follow-up results from the randomized trial. Study Design: A prospective, randomized, placebo-controlled, interventional clinical trial. A power calculation was based on a previous feasibility trial. Setting: University medical centers. Methods: After a 4 year enrollment phase, 381 patients with chronic radicular pain persisting beyond 4 months, who failed conservative treatments, were screened. Ninety patients were enrolled. Patients were randomly assigned to receive percutaneous epidural lysis of adhesionsor placebo with concealed allocation in permuted blocks of 4 to 8 patients each, and stratified by treatment center. The primary outcomes were a mean change of the Oswestry Disability Index (ODI) scores and Visual Analog Scale (VAS), one and 10 years after intervention. For each rating scale an analysis of variance with the within-patient factor time (baseline, one year follow-up, 10 year follow-up) and the between-patient factor treatment (lysis, placebo) was used. Results: Homogeneity was shown at baseline between the groups. The ODI and VAS scores were significantly better one and 10 years in the lysis group vs the control group. The ODI in the lysis group improved from 55.3 ± 11.6 to 9.6 ± 9.3 after one year and to 11.7 ± 14.2 after 10 years. The placebo group also improved from 55.4 ± 11.5 to 30.7 ± 14.2 after one year and to 24.8 ± 12.0 after 10 years. The VAS improved from 6.7 ± 1.1 to 1.2 ± 1.1 after one year and to 1.5 ± 1.4 after 10 years in the lysis group and from 6.7 ± 1.1 to 2.8 ± 1.5 after one year and to 2.9 ± 1.3 after 10 years after placebo intervention. The statistical difference of the ODI and VAS between the treatment and control groups remain significant up to 10 years. No treatment-related severe adverse effects occurred within the 10 years, but minor transient neurological effects were seen directly after the intervention. Limitations: The long-term effects of single treatment components cannot be specified as no imaging examination was performed at 10 year follow-up. A large variety of unanalyzed noninvasive treatments were done within the 10 years. Some patients did not clearly remember the intervention after 10 years. Uncontrolled effects such as higher in homogeneity of biometric properties, concomitant therapies, pain tolerance level, or just social effects could occur, but were not analyzed in the trial. Conclusion: This is the first 10 year follow-up report of a placebo-controlled RCT showing efficacy of the minimally invasive percutaneous adhesiolysis procedure for patients with chronic lumbosacral radicular pain. No alternative evidence-based treatment modality with 10 year follow-up is available to be recommended. This procedure should be considered as the first treatment option for patients with chronic lumbosacral radicular pain.