IPD Coupled Decompression of Degenerative Spinal Stenosis: Comparative Results with Traditional Methods

Abstract

Introduction The goal of this study was to obtain the success rate of decompression with concomitant interspinous process distraction device (IPD) implantation for degenerative lumbar spinal stenosis (DLSS) and to compare the results to historical series treated with traditional decompression with or without posterolateral (PL) instrumented fusion. Material and Methods This study prospectively analyzed the success rates of 18 DLSS patients treated with decompressive surgery and implantation of soft IPD (DIAM) at one or two levels. We compared the results with a historic group of 20 patients which were treated with traditional surgical decompression with or without PL fusion at one or two levels. In the DIAM group, outcomes were measured with the Zurich Claudication Questionnaire (ZCQ) and the short form health survey 36 (SF-36), completed preoperatively and at 6, 12, 24, and 48 months postoperatively. In the historic group, outcomes were measured with the ZCQ preoperatively and at 20.5 ± 10.5 months. The groups were compared in ZCQ results at 24 months. In the DIAM group, postoperative X-rays taken at 4 years were examined for erosions or fractures of the spinous processes Results The operating time was 89 (± 29) minutes in the DIAM and 139 (± 40) minutes in historic group. The blood loss was 265 (± 308) mL in the DIAM and 913 (± 630) mL in the historic group. The hospital stay was 6.3 (±2.4) days in the DIAM and 9.6 (± 5.4) days in the historic group. The narcotic use was 2.3 (± 1.5) days in the DIAM and 4.6 (± 2.6) days in the historic group. Overall, 61.1% (11/18) in the DIAM and 70% (14/20) of the patients in the historic group were considered to be clinically successful. In the DIAM group, SF-36 results significantly improved on follow-up at 6 months and continued to improve to 4 years. No erosions or fractions of the spinous processes were found on the X-rays in the DIAM group at the latest follow-up at 48 months. Conclusion The adjunct of a soft IPD to the decompression has provided patients with comparative results to traditional surgical methods. The main advantages of decompression coupled with soft IPD implantation for DLSS are shorter operating time, less blood loss, less hospital stay, and less narcotic use. The main disadvantage is increased cost of surgery.