DYNAMIC DEVICES FOR DECOMPRESSION OF THE LUMBAR SPINE: 1- AND 2-YEAR RESULTS OF PATIENTS WITH INTERMITTENT NEUROGENIC CLAUDICATION

Abstract

Introduction: Lumbar spinal stenosis (LSS) is a condition involving the narrowing of either the spinal canal or neural foramina and may lead to intermittent neurogenic claudication (INC). Traditionally LSS is been treated by conservative therapy followed by decompression and, if required, stabilizing of the lumbar spine for non-responders. Current results indicate that decompression may lead to increase of biomechanical stresses at levels adjacent to the operated level causing degenerative disorders.

In the last years dynamic devices represent an alternative for the more invasive decompression surgery.

Currently a registry is maintained to collect data on patients implanted with the X STOP.

Methods: Patients who were diagnosed with LSS and planned for an implantation of the X STOP were included in the study. Diagnosis was confirmed by CT or MRI scans. Outcome was measured by the Zurich Claudication Questionnaire measuring symptom severity (SS), physical function (PF), and patient satisfaction (PS). An analysis was performed for the patient who completed the pre-operative and either the 1-year follow-up or 2-year follow-up assessment.

Results: 283 patients participated in the study by completing either the questionnaires by the patient or data forms by the specialist. From these 89 patients completed the pre-operative and 1-year assessment and 20 completed the pre-operative and 2-year assessment.

The results showed a clinical significant change for the domains SS and PF for both 1-year follow-up and 2-year follow-up. For the domain PS the mean score is 1.81 (very satisfied = 1, somewhat satisfied = 2).

The clinically significant success rate based on clinically improvement in 2 of the 3 domains is 71.9% and 65.0 % after respectively 1-year and 2-year follow-up.

Discussion: Our results suggest that intermediate term clinical outcomes of X STOP IPD surgery are stable over time although it may indicate that over time a decrease in clinical significant improvement may be observed. As INC caused by LSS is an ongoing degenerative disease, this may be explained by the ongoing degenerative process.