A Case of Implant Migration Following Bi-level Cervical Disc Arthroplasty

To the Editor: A 48‐year‐old female underwent C4/5 and C5/6 Bryan cervical disc arthroplasty 3 years earlier for right shoulder pain and right arm numbness and weakness. The symptoms resolved postoperatively, and the location of the implant was good 6 weeks after the surgery; however, the range of motion (ROM) of the C4/5 and C5/6 implant were only 1° and 4°, respectively. The patient complained of the right shoulder pain and swallowing difficulty 10 months postoperatively. She experienced no neurological symptoms, and physical examination revealed no abnormal findings. Her symptoms progressively deteriorated, and she began to have difficulty of swallowing solid food. Thirteen months after the surgery, anteroposterior and lateral radiographs showed anterior migration of the C4/5 and C5/6 implants [Figure 1]. Preoperative serum procalcitonin, erythrocyte sedimentation rate, and C‐reactive protein levels were normal. Cervical computed tomography revealed that the C4/5 and C5/6 implants had subsided into the adjacent vertebral endplates. Contrast esophagography suggested that the C5/6 implant contacted, but was not compressing, the posterior esophageal wall. Cervical magnetic resonance imaging demonstrated no spinal cord compression. The chosen surgical procedure was corpectomy of the C5 vertebral body, and autogenous iliac bone graft fusion, revealing that both the C4/5 and C5/6 implants were deformed. There was no bony ingrowth between the C5/6 implant and the adjacent vertebral endplate. Bacterial culture of the resected tissue was negative.