Cost effectiveness of disc prosthesis versus lumbar fusion in patients with chronic low back pain: randomized controlled trial with 2-year follow-up

Abstract

This randomized controlled health economic study assesses the cost-effectiveness of the concept of total disc replacement (TDR) (Charité/Prodisc/Maverick) when compared with the concept of instrumented lumbar fusion (FUS) [posterior lumbar fusion (PLF) /posterior lumbar interbody fusion (PLIF)]. Social and healthcare perspectives after 2 years are reported. In all, 152 patients were randomized to either TDR (n = 80) or lumbar FUS (n = 72). Cost to society (total mean cost/patient, Swedish kronor = SEK, standard deviation) for TDR was SEK 599,560 (400,272), and for lumbar FUS SEK 685,919 (422,903) (ns). The difference was not significant: SEK 86,359 (-45,605 to 214,332). TDR was significantly less costly from a healthcare perspective, SEK 22,996 (1,202 to 43,055). Number of days on sick leave among those who returned to work was 185 (146) in the TDR group, and 252 (189) in the FUS group (ns). Using EQ-5D, the total gain in quality adjusted life years (QALYs) over 2 years was 0.41 units for TDR and 0.40 units for FUS (ns). Based on EQ-5D, the incremental cost-effectiveness ratio (ICER) of using TDR instead of FUS was difficult to analyze due to the "non-difference" in treatment outcome, which is why cost/QALY was not meaningful to define. Using cost-effectiveness probabilistic analysis, the net benefit (with CI) was found to be SEK 91,359 (-73,643 to 249,114) (ns). We used the currency of 2006 where 1 EURO = 9.26 SEK and 1 USD = 7.38 SEK. It was not possible to state whether TDR or FUS is more cost-effective after 2 years. Since disc replacement and lumbar fusion are based on different conceptual approaches, it is important to follow these results over time.

Fig. 1

Comparative health economic analyses were performed between TDR using either Charité, Prodisc or Maverick and instrumented lumbar FUS, performed either as PLF (posterior lumbar fusion), or as a PLIF (posterior lumbar interbody fusion). Analyses of statistical significance were performed as Intention to treat, which was the same as per protocol, as there were no crossovers in this study

Fig. 2

Area under the curve, demonstrating total improvement after 2 years. EQ-5D: 0 = ”death”, 1 = ”perfect quality of life”. Larger area indicates better gain in quality of life. Bold and italic total disc replacement; hatched instrumented fusion

Fig. 3

Cost-effectiveness plane illustrating ICER for TDR compared with FUS. ICER is located in the south-east quadrant, indicating that TDR was less costly and slightly more effective. However not significantly so. *Difference (Δ) in costs and effects between TDR and FUS. Minus in costs and plus in effects favors TDR. Statistics: Bootstrapping was used. The dotted area represents the uncertainty (“uncertainty box”), with representations in all four quadrants, illustrating the uncertainty in the calculations