Background: Dementia following spine fusions is not described in the literature. Also, the impact of new onset dementia on long-term health care utilization is not described. The aim of our study was to define the incidence of new onset dementia and its long-term health care utilization in elderly patients.

Materials and methods: MarketScan database were queried using the ICD-9/10 and CPT 4th edition, from 2001 to 2019. We included patients ≥ 55 of age who underwent spine fusions with at least 5 years follow-up. Outcomes were new onset dementia (> 6 months after the procedure) length of stay (LOS), discharge disposition, hospital re-admissions, outpatient services, and medication refills.

Results: Of 45,129 patients who underwent spine fusions, 1283 patients (2.84%) were diagnosed to have new-onset dementia. There was no difference in the re-operation rates among the dementia and non-dementia cohort at 1-, 2- and 5-years following the index procedure. Patients in the dementia cohort incurred higher number of hospital re-admissions up to 5-years after the index procedure. In terms of combined index procedure and post-discharge utilization payments, significant differences were noted among the dementia vs. non-dementia cohorts at 5-years ($126,628 vs. $ 77,098), following the index procedure.

Conclusion: Elderly age, higher comorbidities, Medicare insurance, multi-level lumbosacral fusions were identified as risk markers for developing dementia following spine fusions. Dementia resulted in significantly higher health care utilization with no increased rate of re-operations for up to 5-years following the index procedure.