IPD without bony decompression versus conventional surgical decompression for lumbar spinal stenosis: 2-year results of a double-blind randomized controlled trial

• Published in: European spine journal 2015-10, Vol.24 (10), p.2295-2305
• Main Authors: Moojen, Wouter A., Arts, Mark P., Jacobs, Wilco C. H., van Zwet, Erik W., van den Akker-van Marle, M. Elske, Koes, Bart W., Vleggeert-Lankamp, Carmen LAM, Peul, Wilco C.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Decompression, Surgical; Female; Humans; Intervertebral Disc - surgery; Lumbar Vertebrae - surgery; Male; Medicine; Medicine & Public Health; Middle Aged; Neurosurgery; Original Article; Spinal Stenosis - surgery; Surgical Orthopedics
• ISSN: 0940-6719; 1432-0932
• DOI: 10.1007/s00586-014-3748-2

Purpose Interspinous process devices (IPDs) are implanted to treat patients with intermittent neurogenic claudication (INC) based on lumbar spinal stenosis. It is hypothesized that patients with lumbar spinal stenosis treated with IPD have a faster short-term recovery, an equal outcome after 2 years and less back pain compared with bony decompression. Methods A randomized design with variable block sizes was used, with allocations stratified according to center. Allocations were stored in prepared opaque, coded and sealed envelopes, and patients and research nurses were blind throughout the follow-up. Five neurosurgical centers (including one academic and four secondary level care centers) included participants. 211 participants were referred to the Leiden–The Hague Spine Prognostic Study Group. 159 participants with INC based on lumbar spinal stenosis at one or two levels with an indication for surgery were randomized into two groups. Patients and research nurses were blinded for the allocated treatment throughout the study period. 80 participants received an IPD and 79 participants underwent spinal bony decompression. The primary outcome at long-term (2-year) follow-up was the score for the Zurich Claudication Questionnaire. Repeated measurement analyses were applied to compare outcomes over time. Results At two years, the success rate according to the Zurich Claudication Questionnaire for the IPD group [69 % (95 % CI 57–78 %)] did not show a significant difference compared with standard bony decompression [60 % (95 % CI 48–71 %) p value 0.2]. Reoperations, because of absence of recovery, were indicated and performed in 23 cases (33 %) of the IPD group versus 6 (8 %) patients of the bony decompression group ( p