A multicenter, prospective, randomized trial evaluating the X STOP interspinous process decompression system for the treatment of neurogenic intermittent claudication: two-year follow-up results.

STUDY DESIGN: A randomized, controlled, prospective multicenter trial comparing the outcomes of neurogenic intermittent claudication (NIC) patients treated with the interspinous process decompression system (X STOP) with patients treated nonoperatively.

OBJECTIVE: To determine the safety and efficacy of the X STOP interspinous implant.

SUMMARY OF BACKGROUND DATA: Patients suffering from NIC secondary to lumbar spinal stenosis have been limited to a choice between nonoperative therapies and decompressive surgical procedures, with or without fusion. The X STOP was developed to provide an alternative therapeutic treatment. METHODS.: 191 patients were treated, 100 in the X STOP group and 91 in the control group. The primary outcomes measure was the Zurich Claudication Questionnaire, a patient-completed, validated instrument for NIC.

RESULTS: At every follow-up visit, X STOP patients had significantly better outcomes in each domain of the Zurich Claudication Questionnaire. At 2 years, the X STOP patients improved by 45.4% over the mean baseline Symptom Severity score compared with 7.4% in the control group; the mean improvement in the Physical Function domain was 44.3% in the X STOP group and -0.4% in the control group. In the X STOP group, 73.1% patients were satisfied with their treatment compared with 35.9% of control patients.

CONCLUSIONS: The X STOP provides a conservative yet effective treatment for patients suffering from lumbar spinal stenosis. In the continuum of treatment options, the X STOP offers an attractive alternative to both conservative care and decompressive surgery.