The MOTION randomized controlled trial for treatment of lumbar spinal stenosis using the percutaneous mild® procedure: 5-year results

Objective: Long-term outcomes of percutaneous image-guided lumbar decompression for treatment of lumbar spinal stenosis with neurogenic claudication secondary to hypertrophic ligamentum flavum were assessed using extended follow-up of the treatment group in the MOTION prospective, multicenter randomized controlled trial. Originally performed with a control group consisting solely of conventional medical management (CMM-Alone), follow-up of the treatment group was extended to five years and analyzed as a modified intent-to-treat group. Methods: Spinal decompression was performed using the mild® Procedure (Stryker Corporation, Portage, MI, USA), with the treatment group also receiving CMM with no restrictions post-procedure (mild + CMM). Subjective outcomes were measured using validated patient-reported questionnaires including the Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), and Numeric Pain Rating Scale (NPRS). Objective measurements included a validated Walking Tolerance Test (WTT), the rate of subsequent lumbar spine interventions (SLSI), and the occurrence of adverse events. An ad hoc analysis comparing 5-year outcomes for patients who were at least 65 years of age at the time of treatment to those of younger patients was also performed. In addition, long-term (4-year) outcomes were assessed for CMM-Alone patients who subsequently received the mild Procedure for relief of ongoing symptoms (crossover group). Results: As with the 1-, 2- and 3-year follow-up visits, all outcomes at the 5-year visit for the mild + CMM group remained significantly improved over baseline (N = 34, p < 0.0001), with ODI, NPRS back and leg, and ZCQ Symptom Severity and Physical Function improving by 20.6, 2.5, 4.6, 0.9, and 0.7, respectively. Walking times increased 326% from baseline, with three additional SLSI performed since the 3-year follow-up. No device- or procedure-related adverse events were reported over the entire 5-year follow-up period. At 5 years post-treatment, no significant differences in outcomes between older and younger patients were seen for any outcome. No significant differences were found in the crossover group when compared to the mild + CMM group using 4-year follow-up results. Conclusions: The use of the percutaneous mild Procedure, together with CMM, is shown to provide a safe, effective and durable treatment for symptomatic LSS. The procedure appears effective regardless of patient age at the time of treatment. Further, the ability of the mild Procedure to improve patient outcomes does not appear to be affected in those patients whose treatment is delayed by continued use of CMM.