Late Migration of a Bryan Cervical Total Disc Replacement Resulting in Progressive Cervical Myelopathy: A Case Report.

Cervical disc arthroplasty (CDA) is a well-established motion-preserving treatment for cervical degenerative disc disease. The Bryan® Cervical Disc is among the most widely used implants with supportive long-term outcome data; however, late implant migration is a rare occurrence and can result in significant neurologic compromise. A female in her mid-50s with a history of C5-6 Bryan Cervical Disc arthroplasty performed 20 years prior presented with progressive cervical myelopathy. She reported a fall from a horse two years before evaluation. Neurologic examination demonstrated bilateral upper-extremity weakness distal to the C5-6 motor distribution, hyperreflexia, and positive bilateral Hoffmann sign, Spurling test, and Lhermitte's sign without clonus. Cervical radiographs with flexion-extension views demonstrated posterior migration of the C5-6 prosthesis, concerning for canal encroachment. The patient underwent removal of the arthroplasty device with C5-6 anterior cervical fusion, resulting in successful decompression and clinical improvement. Very late posterior migration of a Bryan Cervical Disc arthroplasty can present decades after implantation and may cause progressive cervical myelopathy. New or worsening myelopathic findings in patients with prior cervical disc replacement should prompt urgent evaluation for delayed mechanical failure, including implant migration. Implant removal and conversion to fusion can provide definitive decompression and stabilization with favorable outcomes.