Cost effectiveness analysis of graft options in spinal fusion surgery using a Markov model.

STUDY

DESIGN

Statistical decision model.

OBJECTIVE

To determine the most cost-effective graft option in spinal fusion.

SUMMARY OF BACKGROUND DATA: Spinal fusion has been shown to be an effective technique to treat lumbar degenerative spondylolisthesis. There have been significant advances in bone graft options to improve outcomes related to spinal fusion. RhBMP-2 (RhBMP), iliac crest bone graft (ICBG), local bone alone (LBG), demineralized bone matrix with local bone (DBM), local bone with corticocancellous allograft chips (CCA) have all been used as graft options. There has not been significant research in which graft option is most cost effective.

METHODS

A Markov decision model has been created to identify the most cost-effective graft option for use in spinal fusion to treat 1-level (L4-L5) degenerative spondylolisthesis in a cohort of 60-year-old patients. Costs and effectiveness of successful spinal fusion surgery and revision surgery associated with each graft option was estimated through published data. The quality adjusted life years (QALYs) from these surgeries were compared with the amount of QALYs associated with living with chronic back pain.

RESULTS

: In the base case, the incremental cost-effective ratio for each graft option when compared with living with chronic back pain was $21,308/QALY for ICBG, $16,595/QALY for RhBMP, $21,204/QALY for LBG, $21,287/QALY for DBM, and $28,153/QALY for CCA. Therefore, the most cost-effective graft option in the base case was RhBMP. Sensitivity analysis shows that RhBMP is not the most cost-effective option if the revision rate is significantly raised. If the cost of treatment with RhBMP rises >$42,250 then LBG becomes the likely cost-effective treatment.

CONCLUSIONS

RhBMP is the most cost-effective graft option for L4-L5 fusion for degenerative spondylolisthesis largely due to the reduced rate of revision spine surgery. The increased upfront cost and list of complications associated with RhBMP is offset by the reduced rate of revision surgery.