1-2 Level Lateral Single Position Surgery is Highly Cost-Effective in the Treatment of Surgically Indicated Degenerative Lumbar Spinal Pathology

BACKGROUND: The cost-utility of lumbar fusion remains variable and poorly validated, with debate regarding its value. This study aimed to evaluate the cost-effectiveness of 1-2 level Lateral Single Position Anterio-Posterior Fusion Surgery (LSPS) using prospectively collected patient-reported outcome measures (PROMs) to derive cost per QALY estimates over two years. PURPOSE: To evaluate the cost-effectiveness of 1-2 level Lateral Single Position Anterio-Posterior Fusion Surgery (LSPS) using prospectively collected patient-reported outcome measures (PROMs) to derive cost per quality-adjusted life year (QALY) estimates over two years. STUDY DESIGN/SETTING: Prospective consecutive cohort study conducted at a tertiary spine centre. PATIENT SAMPLE: A cohort of 90 patients undergoing primary 1-2 level LSPS between 2020 and 2023. OUTCOME MEASURES: EuroQol 5 Dimension (EQ5D-3L), Oswestry Disability Index (ODI), QALYs, total costs, cost per QALY. METHODS: EuroQol 5 Dimension (EQ5D-3L) and Oswestry Disability Index (ODI) scores were collected pre-operatively and at 3, 6, 12, and 24 months. QALYs were calculated using the improvement in health index score at each timepoint relative to pre-operatively. All costs were included at 2022 values using publicly available data and discounted at 3.5% while health index at 3% annually. Costs were reported in USD, and the cost-effectiveness was evaluated against World Health Organization (WHO) willingness-to-pay models based on gross domestic product (GDP) per capita. RESULTS: 90 patients underwent 1-2 level LSPS, mean age 65.6 years, BMI 28.0 kg/m², 37% male. EQ5D-3L index values improved from 0.55 at baseline to 0.78 at one-year and two-year follow-up (p<0.001), reflecting a QALY gain of 0.227. Mean ODI improved from 40 to 16 at 1-year and 15 at 2-year follow-up (p<0.001). The mean cost of the procedure was $27,413 USD (IQR $21,069-$32,059 USD). 4.4% required rehabilitation and 6.7% required re-operation within 2-years (3.3% decompression at index level, 2.2 % decompression at adjacent level and 1.1% fusion at adjacent level). Contributors to total costs included device costs ($12,603 USD; 46% of total), hospital charges ($7,442 USD, 27%), medical fees ($5,882 USD, 21%), and inpatient rehabilitation (0.7%). Cost per QALY decreased markedly over time, reaching $104,254 USD at 1 year to $46,736 USD at 2 years. By 20 months post-operatively, the cost per QALY met the WHO-CHOICE 'highly cost effective' benchmark of <1× GDP/capita (∼$65,078 USD) and fell within the empirically derived 0.5-1.5× GDP range ($32,539-$97,617 USD/QALY), indicating high cost-effectiveness. CONCLUSION: 1-2 level LSPS is a highly cost-effective procedure for the treatment of degenerative lumbar spinal pathologies that are surgically indicated.