X-STOP: THE ONE YEAR CLINICAL RESULTS AT A SINGLE CENTRE

Abstract

Introduction: This prospective observational study reports on the clinical efficacy of a complete case series of patients who have had X STOP interspinous device insertion for the treatment of lumbar spinal stenosis.

Methods: 60 patients were enrolled and asked to complete the ZCQ, ODI, SF-36 and VAS questionnaire’s pre-operatively, and at 3-, 6- and 12 months post-operatively. Clinical significance with the ZCQ is accepted as improvement in 2 of the 3 domains (where the changes correspond to a mean decrease of 0.42 or 0.46 for symptom severity or physical function respectively, or there is a mean patient satisfaction score of 2.4 or less). Changes in ZCQ were measured at each time point and compared to pre-operative levels.

Results: The mean age was 70 (range 54–90), M:F 29:30. Two of the 59 patients were withdrawn due to intra-operative spinous process fracture and unrelated death. 60% underwent single level and 40% double level insertion.

The ZCQ, ODI, SF-36 and VAS were completed preoperatively and at 12 months by 54, 50, 52, 52 respectively.

Thirty-nine patients completed all questionnaires at all time points and the maximal clinical efficacy was evident 3 months post-operatively. Clinical significant improvement was maintained at the 6- and 12 month post-operative follow-ups despite a minimal loss of clinical efficacy in absolute mean values.

Overall, clinically significant response was achieved in 65%. Seventy-one per cent of double level patients and 61% of single level patients as determined by the ZCQ, had a clinically significant response. Corresponding changes were seen in VAS and ODI and SF-36.

Ten patients (18%) required caudal epidural for recurrence of symptoms and 1 patient required perifacet injections for back pain.

Conclusion: X STOP offers a safe reversible treatment for symptomatic spinal stenosis. Clinically significant improvement is present at three months and is maintained at 12 months.