Midterm clinical and radiologic outcomes after percutaneous interspinous spacer treatment for neurogenic intermittent claudication

Purpose To evaluate the midterm clinical and radiologic outcome of percutaneous interspinous process spacer (IPS) treatment for neurogenic intermittent claudication (NIC) in patients who fail conservative treatment. Methods Consecutive patients with NIC, lumbar spinal stenosis confirmed on magnetic resonance imaging, failure of conservative management for at least 6 months, and treatment with percutaneous IPS were included. Visual analog scale (VAS) and Oswestry Disability Index (ODI) scores were recorded at baseline, 1 month, 1 year and 3 years after treatment. Spinal canal and foraminal cross-sectional areas were calculated from multidetector computed tomography at baseline and 1 year. Results There were 80 patients treated with 94 IPS devices; 83% of patients received a single IPS; 78% of IPS devices were placed at L4-L5. An IPS dislocation was the single periprocedural major complication. VAS score of 8.1 ± 2 before treatment was reduced to 4.4 ± 2 at 1 month after treatment (P =.0001); ODI score of 23.3 ± 10 before treatment was reduced to 11.7 ± 8.5 at 1 month after treatment (P =.0001). These significant reductions were durable at 1-year and 3-year follow-up evaluations (P <.01). Spinal canal and foraminal cross-sectional area increased by 15% at 1 year (P =.0001). Conclusions Patients with NIC who failed conservative treatment and were treated with percutaneous IPS achieved significant gains in pain relief and reduced disability that remained durable at 3-year clinical follow-up evaluation. This outcome was accompanied by significant increases in spinal canal and foraminal cross-sectional areas at the treated level.