Interspinous device versus laminectomy for lumbar spinal stenosis: A comparative effectiveness study

Background context Currently no studies directly compare effectiveness between interspinous devices (IDs) and laminectomy in lumbar spinal stenosis (LSS) patients. Purpose To compare reoperations, complications, and costs between LSS patients undergoing ID placement versus laminectomy. Study design Retrospective comparative study. Patient sample The MarketScan database (2007-2009) was queried for adults with LSS undergoing ID placement as a primary inpatient procedure. Outcome measures Reoperation rates, complication rates, and costs. Methods Each ID patient was matched with a laminectomy patient using propensity score matching. Reoperations, complications, and costs were analyzed in patients with at least 18 months postoperative follow-up. The authors did not receive funding from any external sources for this study. Results Among 498 inpatients that underwent ID placement between 2007 and 2009; the average age was 73 years. The cumulative reoperation rates after ID at 12 and 18 months were 21% and 23%, respectively. The average inpatient hospitalization lasted 1.6 days with an associated cost of $17,432. Two propensity-matched cohorts of 174 patients that had undergone ID versus laminectomy were analyzed. Longer length of stay was observed in the laminectomy cohort (2.5 days vs. 1.6 days, p<.0001), whereas ID patients accrued higher costs at index hospitalization ($17,674 vs. $12,670, p=.0001). Index hospitalization (7.5% vs. 3.5%, p=.099) and 90-day (9.2% vs. 3.5%, p=.028) complications were higher in the laminectomy cohort compared with the ID cohort. The ID patients had significantly higher reoperation rates than laminectomy patients at 12 months follow-up (12.6% vs. 5.8%, p=.026) and incurred higher cumulative costs than laminectomy patients at 12 months follow-up ($39,173 vs. $34,324, p=.289). Conclusions Twelve-month reoperation rates and index hospitalization costs were significantly higher among patients who underwent ID compared with laminectomy for LSS.