270 Very Long-Term Outcomes of Single-Level Minimally Invasive Tubular Lumbar Microdiscectomy With > 10 Years Follow-up

INTRODUCTION: Minimally invasive tubular microdiscectomy is an effective treatment for lumbar radiculopathy with similar outcomes to open approaches based on short and mid-term data. METHODS: Consecutive patients who underwent tubular microdiscectomy for lumbar radiculopathy from May 1, 2010, to July 31, 2013 by a single surgeon at our institution were retrospectively reviewed. We measured VAS leg, VAS back, Oswestry Disability Index (ODI), EQ-5D-3L and EQ-VAS scores as well as achievement of minimal clinically important difference (MCID). Multivariate analysis was conducted for all patient self-reported outcomes, reoperation and length of stay. RESULTS: 103 consecutive patients were included, with a mean age of 52.0 ± 14.9 years, and 52 (50.5%) were female. Patients were assessed at baseline, short-term (6 weeks), long-term (3.8 ± 1.2 years), and very long-term (11.6 ± 1.4 years) follow-up. All outcome measures significantly improved after surgery and continued to improve over time with longer follow-up. More patients met the MCID for EQ-5D, EQ-VAS or any outcome measure at longer-term follow-up. A total of 6 patients (5.8%) had incidental durotomy, and a total of 9 patients (8.7%) needed reoperation. Multivariate analysis shows Worker’s Compensation Board (WCB) status was an independent predictor for length of stay on initial admission and poor ODI at 6-weeks. BMI>30 was an independent predictor for not achieving MCID for VAS leg at very long-term follow-up and increased need for reoperation CONCLUSIONS: We report sustained improvement after tubular microdiscectomy with > 10 years follow-up. WCB status and BMI >30 were associated with worse outcome at short and long-term follow-up respectively.