A randomized controlled trial of the X-Stop interspinous distractor device versus laminectomy for lumbar spinal stenosis with 2-year quality-of-life and cost-effectiveness outcomes

OBJECTIVE: Lumbar spinal stenosis (LSS) is a common and debilitating condition that is increasing in prevalence in the world population. Surgical decompression is often standard treatment when conservative measures have failed. Interspinous distractor devices (IDDs) have been proposed as a safe alternative; however, the associated cost and early reports of high failure rates have brought their use into question. The primary objective of this study was to determine the cost-effectiveness and long-term quality-of-life (QOL) outcomes after treatment of LSS with the X-Stop IDD compared with surgical decompression by laminectomy. METHODS: A multicenter, open-label randomized controlled trial of 47 patients with LSS was conducted; 21 patients underwent insertion of the X-Stop device and 26 underwent laminectomy. The primary outcomes were monetary cost and QOL measured using the EQ-5D questionnaire administered at 6-, 12-, and 24-month time points. RESULTS: The mean monetary cost for the laminectomy group was £2712 ($3316 [USD]), and the mean cost for the X-Stop group was £5148 ($6295): £1799 ($2199) procedural cost plus £3349 mean device cost (£2605 additional cost per device). Using an intention-to-treat analysis, the authors found that the mean quality-adjusted life-year (QALY) gain for the laminectomy group was 0.92 and that for the X-Stop group was 0.81. The incremental cost-effectiveness ratio was -£22,145 (-$27,078). The revision rate for the X-Stop group was 19%. Five patients crossed over to the laminectomy arm after being in the X-Stop group. CONCLUSIONS: Laminectomy was more cost-effective than the X-Stop for the treatment of LSS, primarily due to device cost. The X-Stop device led to an improvement in QOL, but it was less than that in the laminectomy group. The use of the X-Stop IDD should be reserved for cases in which a less-invasive procedure is required. There is no justification for its regular use as an alternative to decompressive surgery. Clinical trial registration no.: ISRCTN88702314 (www.isrctn.com).