Payment Model Evolution for Spinal Fusions.

Value-based payment reform in the United States is rapidly evolving, with new models from the Centers for Medicare & Medicaid Services targeting a range of inpatient and outpatient procedures. To trace this evolution, we examine spinal fusion-a procedure consistently included in past and emerging models-as a lens to compare model characteristics, payment structure, quality measurement, and primary care integration. We analyze Bundled Payments for Care Improvement-Advanced (BPCI-A, 2018 to 2025), Transforming Episode Accountability Model (TEAM, launched in 2026), Advancing Chronic Care with Effective, Scalable Solutions (ACCESS, launching in July 2026), Ambulatory Specialty Model (ASM, launching in 2027), and proposed condition-based bundled payments. BPCI-A laid the groundwork for bundled spinal fusion payments but was voluntary and lacked integration with primary care. TEAM and ASM mandate participation from inpatient and outpatient specialists, respectively; TEAM also requires primary care referrals after discharge. ACCESS incorporates technology tools into specialty care, while condition-based bundles embed specialty care within Accountable Care Organizations; both prioritize longitudinal care integration. We conclude that future reforms should combine aspects of the aforementioned models, prioritizing primary care-specialist collaboration, integration of acute and chronic care pathways, and quality metrics that reflect patient outcomes.