Comparison of adverse events between the Bryan artificial cervical disc and anterior cervical arthrodesis

Study Design. Randomized controlled study. Objective. To compare the rates of adverse events associated with disc arthroplasty versus those of anterior cervical discectomy and arthrodesis with allograft and plate. Summary of Background Data. Cervical disc arthroplasty as a substitute for fusion has been developed to maintain motion and, theoretically, prevent adjacent segment degeneration. Currently, cervical arthroplasty devices are undergoing clinical testing for safety and efficacy. The evaluation of safety is performed by critical analysis of all adverse occurrences following surgery to determine if the new device has a beneficial risk profile for the patient. Methods. Adverse events associated with Bryan Disc arthroplasty and arthrodesis were compared in a prospective randomized study. Four hundred sixty-three (463) patients having cervical radiculopathy and or myelopathy at a single level were treated at 31 sites. A total of 242 patients received the disc and 221 patients had anterior cervical discectomy and fusion. All patients were evaluated before surgery and at 1.5, 3, 6, 12, and 24 months after surgery. Adverse events were recorded concurrently and categorized by severity and as medically or surgically related. Results. No differences in overall medical events occurred between groups. Surgically related events occurred more frequently in the investigational group secondary to more complaints of postoperative dysphagia and late medical events occurred more frequently in the investigational patients. However, the more severe World Health Organization Grade 3 and 4 events occurred more frequently in the arthrodesis patients related to treatment of pseudarthrosis and persistent symptoms. Significantly, more cervical spine reoperations occurred in the fusion group. Only one spinal cord injury occurred and it was in the arthrodesis group and no patients had deep infection or death related to either procedure. Conclusion. Bryan cervical disc replacement and anterior cervical fusion are both safe procedures with a low incidence of significant adverse events related to the procedure. Statistically, more serious adverse events and reoperations occurred in the fusion group while a greater number of less serious surgically related events were seen in the investigational group.