One-year results of X Stop interspinous implant for the treatment of lumbar spinal stenosis.

STUDY DESIGN

Prospective observational study.

OBJECTIVE

To prospectively assess the clinical outcome of patients with symptomatic lumbar spinal stenosis before and at periodic intervals after X Stop implantation and to compare the data with previous studies.

SUMMARY OF BACKGROUND DATA

The X Stop Interspinous Process Distraction Device is a relatively new interspinous implant designed for patients with symptomatic spinal stenosis particularly neurogenic claudication. Previously, a randomized study has shown a 75% improvement in symptoms and physical function at 1-year post-X Stop implantation for lumbar spinal stenosis. The only other study is a preliminary report of only 10 patients with variable intervals of clinical outcome assessment.

METHOD

Forty consecutive patients were enrolled and surgically treated with X Stop implantation. The X Stop device was implanted at the stenotic segment, which was either at 1 or 2 levels in each patient. They were clinically evaluated at the preoperative, 3-month, 6-month, and 1-year stage with clinical questionnaires (Zurich Claudication Questionnaire, Oswestry Disability Index, and SF-36).

RESULTS

Sixteen patients failed to complete all the questionnaires at all time intervals and hence were excluded, leaving 24 patients who had completed all questionnaire at all time interval. By 12 months, 54% of these 24 patients reported clinically significant improvement in their symptoms, 33% reported clinically significant improvement in physical function, and 71% expressed satisfaction with the procedure. 29% of the patients required caudal epidural after 12 months after surgery for recurrence of their symptoms of neurogenic claudication.

CONCLUSION

The results of this prospective observational study indicate that X Stop offers significant short-term improvement over a 1-year period. It is a safe, effective, and less invasive alternative for treatment of lumbar spinal stenosis. Our results, however, are less favorable than the previous multicenter, randomized study.