X STOP versus Decompression for Neurogenic Claudication: Economic and Clinical Analysis

Abstract

Introduction: The X STOP is the first Interspinous Process Decompression (IPD) device that is proven to be superior to nonoperative therapy in patients with neurogenic intermittent claudication secondary to lumbar spinal stenosis (LSS) in a multicenter randomized study at 1 and 2 years. The clinical success rate in the X STOP IPD group was comparable to that reported for laminectomy. The goal of the current study was to compare the clinical effectiveness and direct hospital costs of IPD with the X STOP implant to those of laminectomy in patients with LSS. Methods: Thirty patients with LSS treated surgically were matched for age and length of follow-up. Eighteen of thirty patients had X STOP implantation and twelve of thirty had laminectomy. The pre and post-operative Oswestry scores and hospital charges for the two groups were compared. An absolute improvement of 15 ODI points was selected to define an individual patient success. Results: Twelve of 18 X STOP patients (67%) were treated at one level and six of 18 (33%) at two levels. Three of 12 laminectomy patients (25%) were treated at one level and nine of 12 (75%) at two levels. The average age was 68 years (SD 12.5) for X STOP patients and 69 years (SD 7.9) for laminectomy patients. Six of the 18 X STOP patients (33%) had grade I degenerative spondylolysthesis at the treated level versus two of 12 patients (17%) in the laminectomy group. The minimum follow-up was 45 months in the X STOP group and 43 months in the laminectomy group. The average follow-up was 51 months in the X STOP group (SD 5.3) and 52 months in the laminectomy group (SD 5.3). Pre-operative average ODI score in the X STOP group was 45 vs. 36 in the laminectomy group (p>0.1560). Post-operative average ODI score in the X STOP group was 15 and 24 in the laminectomy group (p>0.1159). The absolute ODI change was 29 points for the X STOP group, and 12 points for the laminectomy group (p<0.0186). The relative ODI change was 64% for the X STOP group, and 29% for the laminectomy group (p<0.0369). Based on the selected success criterion (ODI improvement of at least 15 points), fourteen of 18 (78%) X STOP procedures were considered successful and four of 12 (33%) laminectomy procedures were deemed successful (p<0.0243). Average direct hospital costs for 1 level X STOP and 1 level laminectomy group were $15,980 and $45,302 respectively (p<0.0001). Average hospital costs for 2 level X STOP and 2 level laminectomy groups were $25,618 and $46,752 respectively (p<0.0010). The main savings in the X STOP group (cost drivers) were in OR costs (shorter operative time), hospital charges (X STOP is an outpatient procedure) and anesthesia charges (X STOP is placed under local/ MAC anesthesia). Discussion: The present study demonstrated that X STOP IPD is clinically at least as effective as laminectomy at 4 year followup based on the ODI scores. The subset of patients with degenerative instability (6 of 18) had equally good results with X STOP treatment and avoided fusion. The somewhat lower scores in the laminectomy group at 4 years could be due to the limited sample size and known deterioration of the success of surgical decompression with time. IPD with the X STOP implant was associated with significantly smaller direct hospital costs compared to laminectomy for the surgical treatment of lumbar spinal stenosis. A single level X STOP IPD is about $29,000 less expensive than a single level laminectomy, and a double level X STOP IPD is about $21,000 less expensive than double level laminectomy. Summary: IPD with X STOP device for the treatment of LSS is clinically at least as effective as standard laminectomy at 4 years post-operatively and provides substantial direct cost savings compared to decompressive surgery. X STOP versus Decompression for Neurogenic Claudication: Economic and Clinical Analysis