Cervical disc arthroplasty (CDA)

CDA addresses symptomatic cervical degenerative disc disease (DDD) causing radiculopathy and/or myelopathy by excising the pathologic disc, preparing the endplates, and implanting an artificial disc prosthesis at the affected interspace. The anterior approach mirrors that of anterior cervical discectomy and fusion (ACDF), and the procedure scope includes decompression, osteophytectomy as needed, and closure—all bundled into the primary CPT code. Unlike fusion, the prosthesis is engineered to replicate native disc biomechanics, maintaining flexibility, preserving spinal curvature, and distributing load more evenly across the motion segment.

CDA is FDA-approved for skeletally mature adults and is most commonly performed at a single cervical level, though multi-level procedures are supported by growing evidence. Because the procedure preserves motion, proponents argue it reduces the mechanical stress transferred to adjacent segments—a phenomenon associated with adjacent segment disease (ASD) after fusion. Long-term randomized controlled trial data generally show non-inferiority or superiority to ACDF on patient-reported outcomes, neurological success, and reoperation rates, though heterotopic ossification and implant-related osteolysis remain recognized complications that can compromise motion preservation and occasionally necessitate revision.

From a utilization standpoint, a large database study (Yale/PMC, 2023) found that CDA usage plateaued relative to ACDF between 2010 and 2021, with CDA patients tending to be younger, less comorbid, and more often treated by orthopedic surgeons than neurosurgeons. Payer coverage is broadly available but consistently requires documented failure of conservative care (typically ≥6 weeks), absence of significant osteoporosis, instability, or active infection, and single- or limited-level disease—criteria that must be explicitly supported in the operative note and pre-authorization request.

Billing CDA under the wrong CPT code—or conflating it with ACDF codes—triggers automatic claim denial and potential post-payment audit because CMS LCD L38033 and major commercial policies (Cigna CMM-602, UHC, Aetna CPB 0591) treat CDA as a distinct covered service with its own medical necessity criteria. Using CPT 22551 (ACDF) instead of 22856 (single-level CDA) not only misdescribes the service but can constitute improper billing; the reverse error (billing 22856 when fusion was actually performed) exposes the practice to overpayment recovery. Additionally, missing or inadequate documentation of failed conservative therapy, symptom duration, and neuroimaging correlation is the leading reason for prior-authorization denial and post-service recoupment across Medicare and commercial payers.