Ahead of Print: A Cost-Effectiveness Comparison Between Open Transforaminal and Minimally Invasive Lateral Lumbar Interbody Fusions Using the Incremental Cost-Effectiveness Ratio at 2-Year Follow-up

BACKGROUND: Direct cost comparisons between minimally invasive spine surgeries and the open options are rare.

OBJECTIVE: To compare healthcare costs associated with open transforaminal lumbar interbody fusion (TLIF) and minimally invasive lateral lumbar interbody fusion (LLIF) by calculating the incremental cost-effectiveness ratio (ICER) and to calculate the thresholds for minimum clinically important difference and minimum cost-effective difference for patient-reported outcome measures at the 2-year follow-up.

METHODS: Forty-five patients who underwent single-level TLIF and 29 patients who underwent single-level stand-alone LLIF were included in the comparison. All costs from diagnosis through the 2-year follow-up were available from a comprehensive single-center data bank within a unified hospital system. Payment provided for all spine-related medical resource use from the time of diagnosis through 2 years was recorded. A 0% discount rate was applied. Quality-adjusted life-years (QALYs) were calculated from the EuroQol-5D collected in an unbiased manner. Difference in total cost per QALY gained for LLIF minus that for TLIF was assessed as the estimate of the ICER from a US perspective.

RESULTS: Significant improvements were observed at the 2-year follow-up for both TLIF and LLIF with the Short Form-36 physical component summary, Oswestry Disability Index, visual analog scale back pain and leg pain scores, and EuroQol-5D. ICER calculations revealed similar mean cumulative QALYs gained at the 2-year interval (0.67 for TLIF and 0.60 for LLIF; P = .33). Median total costs of care after TLIF and LLIF were $44 068 and $45 574, respectively (P = .96). Minimum cost-effective difference thresholds with an anchor of <$50 000 per QALY were higher than minimum clinically important difference thresholds for all patient-reported outcome measures. Total mean cost and EuroQol-5D were statistically equivalent between the 2 treatment groups.

CONCLUSION: TLIF and LLIF produced equivalent 2-year patient outcomes at an equivalent cost-effectiveness profile.

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