The cost effectiveness of single-level instrumented posterolateral lumbar fusion at 5 years after surgery.

STUDY

DESIGN

Cost effectiveness analysis for single-level instrumented fusion during a 5-year postoperative interval.

OBJECTIVE

To determine the cost/quality-adjusted life year (QALY) gained for single-level instrumented posterolateral lumbar fusion for degenerative lumbar spine conditions during a 5-year period.

SUMMARY OF BACKGROUND DATA: Cost/QALY has become a standard measure among healthcare economists because it is generic and can be used across medical treatments. Prior studies have reported widely variable estimates of cost/QALY for lumbar spine fusion. This variability may be related to factors including study design, sample population, baseline assumptions, and length of the observation period.

METHODS

To determine QALY, the Short Form 6D (SF-6D), a utility index derived from the Short Form (36) Health Survey (SF-36) was used. Cost analysis was performed based on actual reimbursements from third-party payors, including those for the index surgical procedure, treatment of complications, emergency room outpatient visits, and revision surgery. A second cost analysis using only the contemporaneous Medicare Fee schedule was also performed, in addition to a subanalysis including indirect costs from days off work.

RESULTS

The mean SF-6D health utility value showed a gradual increase throughout the follow-up period. The mean health utility value gained in each year postoperatively was 0.12, 0.14, 0.13, 0.15, and 0.15, for a cumulative 0.69 QALY improvement during the 5-year interval. Mean direct medical costs based on actual reimbursements for 5 years after surgery, including the index and revision procedures, was $22,708. The resultant cost per QALY gained at the 5-year postoperative interval was $33,018. The analogous mean direct cost based on Medicare reimbursement for 5 years was $20,669, with a resultant cost per QALY gained of $30,053. The mean total work productivity cost for 5 years was $14,377. The resultant total cost (direct and indirect) per QALY gained ranged from $53,949 to $53,914 at 5 years postoperatively.

CONCLUSION

In the future, surgeons will need to demonstrate cost-effectiveness as well as clinical efficacy in order to justify payment for medical and surgical interventions, including lumbar spine fusion. This study indicates that at 5-year follow-up, single-level instrumented posterolateral spine fusion is both effective and durable, resulting in a favorable cost/QALY gain compared to other widely accepted healthcare interventions.