TWO-YEAR CLINICAL AND POSITIONAL MRI RESULTS: OF X STOP INTERSPINOUS DEVICE – A PRELIMINARY REPORT

Abstract

Purpose: To evaluate the changes in lumbar spine kinematics and clinical outcomes of patients with spinal stenosis 2 years after implantation of the X Stop interspinous decompression device.

Methods: 10 patients (6 males; 4 females) underwent X Stop procedure. Age ranged from 57 years to 71 years. 15 levels were operated (5 single levels: L_2-3 - 1, L_4-5 - 4; 5 double levels: L_3-4 +L_4-5 – 4; L_4-5+L₅S₁ – 1). A 0.6 Tesla Upright MRI scanner was used to acquire images in seated (flexion, extension, and neutral) and erect postures at preoperative, 6 months, and 2 years after surgery. The total range of motion of the lumbar spine and the operated segments were measured, along with changes in disc height, areas of the exit foramens, and dural sac. Clinical outcomes were assessed by Zurich Claudication Questionnaire before and 3, 6, 12, and 24 months after surgery.

Results: Mean Zurich Claudication Scores (n=10)

At 6 months, there was a significant increase in the spinal canal and foraminal dimension. However at 2 years there was a reduction in these dimensions such that there was no significant difference from the preop-erative measurements.

Conclusion: The results of this prospective observational study indicate that X Stop offers significant short-term improvement. It is a safe, effective, and less invasive alternative for treatment of lumbar spinal stenosis. The maximum clinical benefit and mechanical efficacy seems to be realized in the early stages postoperatively with gradual reduction thereafter over 2 years. Co-existing co-morbidities such as obesity and osteoarthritis in the lower limbs may influence the clinical results.