Disappearance of Anterior Cervical Corpectomy Cage.

Although cage subsidence and dislodgement are not uncommon in anterior cervical spine surgery, missing cages have seldom been reported. This is the first report of the disappearance of a metallic corpectomy cage after anterior cervical fusion. A 63-year-old man, who had a history of ankylosing spondylitis and diabetes mellitus, was involved in a motor vehicle accident that broke his neck. The traumatic C6 burst fracture caused myelopathy and instability, which required surgery. He then underwent anterior C6 corpectomy with circumferential fixation, including anterior plating and posterior lateral mass screws from C5-C7. There was a significant improvement in neurological function after the surgery and he could ambulate independently. However, upon a visit at six months postoperation, there was dislodgement of the anterior cervical plate and cage. An attempt to revise the anterior fusion construct was made subsequently, but this surgery could only remove the plate. The metallic cage was left in place during the revision surgery because it was firmly incorporated into the C5 and C7 vertebra and could hardly be adjusted intraoperatively. There were no other interventions during the interval. Upon his visit at 23 months after the initial surgery, the metallic cage was missing. No examinations could locate the cage anywhere in the body, including 36-inch radiographs that demonstrated completely the disappearance of the metallic corpectomy cage. The posterior arthrodesis seemed stable and the patient had no dysphagia or any other gastrointestinal symptoms. The process of the disappearance of the corpectomy cage was never noticed by the patient and he remains free of symptoms to date. The complete dislodgement of a cervical corpectomy cage that was placed anteriorly could happen without symptoms. The cage might have been expelled during bowel movements and caused little problem. Failure to achieve arthrodesis in anterior cervical fusion, therefore, must be closely monitored.