Evaluating the Effects of Inpatient Only (IPO) Policy Changes on Anterior Cervical Discectomy and Fusion: Access and Outcomes Across Payer Groups.

Study DesignRetrospective Cohort Study.ObjectiveRemoval of anterior cervical discectomy and fusion (ACDF) from Medicare's Inpatient-Only list in 2017 enabled outpatient reimbursement. Although outpatient ACDF is associated with improved outcomes and lower costs, the impact across payer groups remains unclear, particularly for Medicaid patients.MethodsACDF cases from a national database (2016-2022) were analyzed. Payer groups included Commercial, Medicare, and Medicaid. Multivariable regression adjusted for demographics, comorbidity burden, multilevel fusion, year, and region. Outcomes included complications, 90-day readmissions, and costs.ResultsOutpatient ACDF utilization increased over time but remained lowest among Medicaid patients. Across all payer groups, inpatient surgery was associated with worse outcomes and the magnitude of this difference was greatest in Medicaid patients. Thirty-day complications increased from outpatient to inpatient most prominently in Medicaid patients (OR 1.48). A similar pattern was observed for 90-day readmissions, with the largest increase in Medicaid patients (OR 1.49) and cost (-$5,973).DiscussionOutpatient ACDF provides consistent clinical and economic advantages; however, Medicaid patients remain least likely to receive outpatient care despite the greatest potential benefit, highlighting persistent disparities in access.