The cost effectiveness of dynamic and static interspinous spacer for lumbar spinal stenosis compared with laminectomy

Background: The present study aims to evaluate the cost-effectiveness of Dynamic Interspinous Spacer (Coflex®) and Static Spacer (X-STOP ®) compared to Laminectomy (LAMI) in patients with lumbar spinal stenosis.   Methods: A decision-analysis model was developed to estimate the cost-effectiveness. The effectiveness parameters were obtained from a systematic literature review in relevant databases including PUBMED and EMBASE. A meta-analysis was performed using the STATA statistical package and a random model was used to collect measures of mean difference of visual analogue scale (VAS) pain score before and after intervention in X-stop, Coflex and LAMI (95% confidence intervals). Cost data were obtained from provider and associated literature based on health care provider prospective. We assumed that the probability of the success rate of surgery in each intervention from associated literature and calculated Incremental cost effectiveness ratio. A one-way sensitivity analysis was also carried out.   Results: Twenty-four out of 294 studies are included in the Meta-analysis. The overall pooled estimate of the mean difference of VAS pain score were 3.49 (95% CI 3.7-4.2) and 4.14 (95% CI 3.09-5.19) for X-stop and Coflex, respectively. In addition, we assumed the overall pooled estimate of 5.3 (95% CI 2.15-7.4) on the basis of literature for LAMI. The average cost per LAMI surgery, X-stop and Coflex was US$ 3019, US$ 2022 and US$ 2566, respectively. Incremental cost effectiveness ratio of X-stop and Coflex versus LAMI was US$ 665.9 and US$ 780.7, respectively.   Conclusion: Static Interspinous Spacer (X-stop) appears to be the most cost-effective treatment strategy in base case scenario with success rate of LAMI (range between (55%-70%). A sensitivity analysis shows that the increase probability of success rate of LAMI was more than 70 % and less than 55% which lead to the cost effectiveness of the Coflex intervention.