Metallosis after traumatic loosening of Bryan cervical disc arthroplasty: a case report and literature review

Cervical disc arthroplasty has been a popular alternative to traditional arthrodesis treatment for maintaining postoperative cervical spine mobility. However, certain adverse reactions to cervical disc arthroplasty have emerged during the last few decades. Metallosis or metalloma is a rarely reported complication after spinal fusion or spinal arthroplasty surgery. We report on the first metallosis case occurring in a patient who received Bryan Disc implantation approximately 8 years earlier. She was involved in a traffic accident and sustained a whiplash injury to the cervical spine one and a half years ago. The traumatic Bryan Disc loosening developed after the traffic accident, causing metallosis. To the best of our knowledge, this is the first reported case of spinal metallosis caused by the Bryan Disc. A series of metallosis cases reported in the literature are also reviewed. Although uncommon, intraspinal metallosis or metalloma should be considered as an infrequent cause of delayed neurological symptoms after spinal surgery involving metallic instrumentation, especially after disc arthroplasty. Once metallosis is suspected, immediate metallic implant removal is mandatory for definite diagnosis and treatment.