Comparison of Clinical and Radiographic Outcomes Between Single-Level Bryan and ProDisc-C Cervical Disc Arthroplasty: A 5-year Follow-up Study

Study Design Retrospective cohort study. Objectives To compare 5-year clinical and radiographic outcomes between single-level Bryan and ProDisc-C cervical disc arthroplasty (CDA). Methods Patients undergoing single-level Bryan or ProDisc-C arthroplasty for cervical spondylosis radiculopathy and/or myelopathy between March 2004 and August 2014 were enrolled. Clinical outcomes included Visual Analog Scales for arm/neck pain (VAS-A/N), Neck Disability Index (NDI), and modified Japanese Orthopedic Association (mJOA) scores. Radiographic evaluation included cervical lordosis, range of motion (ROM), functional spinal unit (FSU) height, cervical sagittal vertical axis (cSVA), T1 slope, heterotopic ossification (HO), and adjacent segment degeneration (ASD). Evaluations were performed preoperatively and postoperatively within 3 months, 1 year and 5 years. Results Among 113 patients with 5-year follow-up (51 Bryan, 62 ProDisc-C), both groups showed significant improvements in VAS-N, VAS-A, NDI, and mJOA scores at all timepoints (all P < .001). No significant intergroup differences were detected between the two cohorts at baseline (all P > .05). ROM and cervical alignment remained stable in both cohorts. Compared to Bryan arthroplasty, ProDisc-C demonstrated greater index-level segmental lordosis (4.3° ± 5.0° vs 1.2° ± 4.7°; P = .001), more FSU height restoration (35.2 ± 3.4 mm vs 32.9 ± 3.6 mm; P < .001), and less segmental kyphosis incidence (21.0% vs 39.2%; P = .032). However, ProDisc-C arthroplasty had higher rates of ASD (58.1% vs 37.3%; P = .028) and HO (67.7% vs 33.3%; P < .001). Conclusion Both prostheses achieved comparable 5-year clinical outcomes. ProDisc-C arthroplasty better maintained cervical sagittal alignment, whereas Bryan arthroplasty demonstrated lower ASD and HO incidence.