Is cervical disc arthroplasty noninferior to anterior cervical discectomy and fusion for cervical spondylotic myelopathy? A Spine CORe™ analysis of QOD data

OBJECTIVE: Cervical spondylotic myelopathy (CSM) is a common cause of spinal cord dysfunction, and anterior cervical discectomy and fusion (ACDF) is the gold standard treatment. Cervical disc arthroplasty (CDA) is a relatively novel, motion preserving alternative to ACDF. The aim of this study was to assess CDA versus ACDF in the surgical treatment of CSM at a 5-year follow-up. METHODS: This study used the 14-site Spine CORe™ study group cervical module of the Quality Outcomes Database (QOD), which included 1085 patients. Baseline demographics, clinical variables, and surgical parameters were collected. Patient-reported outcome measures (PROMs) included the EQ-5D, Neck Disability Index (NDI), and numeric rating scale (NRS) for neck pain and arm pain. Of the 1085 patients, 22 patients who underwent CDA with baseline and 5-year follow-up PROMs data who met the inclusion/exclusion criteria were selected. Nearest-neighbor propensity score matching was performed using a 4:1 matching ratio. Five-year PROMs were compared between the CDA and ACDF groups using the 2-sample t-test for continuous variables. Multivariable linear regression was performed to identify predictors of 5-year myelopathy severity. RESULTS: There were 1085 patients in the 14-site Spine CORe™ study group's QOD cervical module; 110 matched patients were analyzed, including 22 who underwent CDA (mean age 47.73 years) and 88 who underwent ACDF (mean age 48.89 years). The subcohort had 100% of PROMs data (NDI, NRS, EQ-5D, and mJOA) at the 5-year follow-up. There were no significant differences for 1- and 2-level operations between the CDA and ACDF groups (p = 0.34). There were no significant differences in 5-year PROMs between the two groups. Patients improved in each PROM category in both treatment groups when comparing baseline with 5-year PROMs. While the rate of reoperation at 5 years was higher in the ACDF group compared with the CDA group, there was no statistically significant difference (17.0% vs 9.1%, p = 0.52). CONCLUSIONS: In appropriately selected patients with CSM, CDA can provide comparable outcomes to ACDF while preserving cervical motion.