COST EFFECTIVENESS OF TWO FORMS OF CIRCUMFERENTIAL LUMBAR FUSION: A PROSPECTIVE RANDOMISED CONTROLLED TRIAL

Abstract

Introduction: A prospective randomised controlled trial of circumferantial spinal fusion has shown superior clinical outcome when a femoral ring allograft (FRA) is used compared to when a titanium cage (TC) is used. The implant cost of the TC is nearly ten fold that of the FRA. However the additional costs of surgery and related costs also need to be considered to determine if there is a real cost advantage of FRA over TC. We can find no previously reported studies which economically evaluate the TC and the FRA in circumferential lumbar spinal fusion. The aim of this study was to investigate cost-effectiveness of TCs in comparison to FRAs for circumferential lumbar spinal fusion over a two year National Health Service (NHS) perspective using a cost-utility evaluation

Methods: This randomised study had the approval of the local ethical committee and the institutional research and development board (Reference OR059844) prior to its commencement. Eighty-three patients were randomly allocated to receive either the TC or FRA as part of a circumferential lumbar fusion between 1998 and 2002. NHS costs related to the surgery and revision surgery needed during the trial period were monitored and adjusted to the base year (2005/6 pounds sterling). The Short Form-6D (SF-6D) was administered preoperatively and at 6, 12 and 24 months in order to elicit patient utility and subsequently Quality-Adjusted Life Years (QALYs) for the trial period. Return to paid employment was also monitored. Bootstrapped mean differences in discounted costs and benefits were generated in order to explore cost-effectiveness.

Results: Baseline demographic data including age, sex, smoking history, previous surgery history and number of operated levels did not differ between the two groups. A significant cost difference of £1,942 (AUD4,255), (95% CI £849 (AUD1,860) to £3,145 (AUD6,891)) in favour of FRA was found. Mean QALYs per patient over the 24 month trial period were 0.0522 (SD 0.0326) in the TC group and 0.1914 (SD 0.0398) in the FRA group, producing a significant difference of −0.1392 (95% CI 0.2349 to 0.0436). With regard to employment, incremental productivity costs were estimated at £185,171 (AUD 405,745) in favour of FRA.

Discussion: From an NHS perspective, the trial data show that TC is not cost-effective in circumferential lumbar fusion. The use of FRA was found to dominate (generating greater QALY gains and less cost). In addition FRA patients reported a greater return to work rate and hence, productivity costs were also in favour of FRA.