A two-year follow-up evaluation for the effectiveness of HeliFix Interspinous Spacer System for the treatment of Degenerative Lumbar Spinal Stenosis with Neurogenic Intermittent Claudication

Presented at SMISS Annual Forum 2014
By Oscar Alves MD, PhD
With M. Fins MD, M. J. Coelho ,

Disclosures: Oscar Alves MD, PhD B; Alphatec Spine. M. Fins MD None, M. Coelho None,

Introduction:
Neurogenic Intermittent Claudication (NIC) frequently results from Degenerative Lumbar Spinal Stenosis (DLSS). Studies suggest that exercise therapies may be beneficial for many patients experiencing NIC. However, a consensus remains lacking on which surgical treatments are most effective, requiring more studies to identify optimal treatment options for patients with recalcitrant NIC.

Aims/Objectives:
The aim of this study was to evaluate whether the treatment of patients with NIC and DLSS using a minimally invasive, motion-preserving, interspinous process decompression system will result in clinical improvement.

Methods:
For a prospective analysis, 30 patients (12 males and 18 females, mean age of 56.5 years) presenting symptomatic NIC with DLSS after prior conservative management were enrolled for this single-site study. Using the HeliFix Interspinous Spacer System, 25 patients were treated at one level, and the remaining patients were implanted at two levels. The PEEK devices were implanted in seven L3-L4 levels, twenty L4-L5 levels and three L5-S1 levels. Patients completed the Zurich Claudication Questionnaire (ZCQ), Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) Questionnaire at baseline and at 3-, 6-, 12- and 24-month follow-ups.

Results:
No intra-operative complication occurred during the surgery, the mean duration of which was 20 minutes (minimum 15 and maximum 65). Two patients were lost to follow-up. One patient had a migrated device, which was removed 7 months after the surgery. The migration was attributed to over-sizing of the implant. The ZCQ score for patient satisfaction showed 83.3% overall satisfaction 3 months post-operatively, and it persisted into 1 year and 2 years post-operatively with 88.9% and 81.5% overall satisfaction, respectively. VAS score of 50.5±19.7 at baseline decreased significantly to 17.7±16.8 by 3 months and further decreased over time to 9.8±12.9 at 2 years. Baseline ODI score of 64.6±24.2 also decreased significantly by 3 months to 20.1±23.5 and was sustained into the second year at 15.6±20.6.

Conclusions:
Multiple efficacy outcomes strongly suggest that patients suffering from Degenerative Lumbar Spinal Stenosis with Neurogenic Intermittent Claudication may achieve clinically significant improvements in pain and quality of life following treatment with the HeliFix Interspinous Spacer System.