Preliminary experience with the DOC dynamic cervical implant for the treatment of multilevel cervical spondylosis

Object. Despite the wide use of anterior cervical instrumentation in the management of multilevel cervical spondylosis, the incidences of pseudarthrosis and instrument-related failure remain high. The use of a dynamic implant may aid in the prevention of these complications. The purpose of this study was to evaluate the DOC dynamic cervical implant in the treatment of multilevel cervical spondylosis. Methods. The authors evaluated 34 cases in which anterior multilevel cervical decompression and fusion were performed using the DOC Ventral Cervical Stabilization System. Postoperatively, and at each follow-up visit, the sagittal angle and the degree of subsidence that developed were measured. Fusion rates and clinical outcomes were also evaluated. The mean postoperative sagittal angle was 14degrees of lordosis. The mean change in the sagittal angle during the follow-up period was 0.4degrees of lordosis. By 6 months postoperatively some subsidence had occurred in most patients, with no subsidence occurring in only 15%. By 3 months greater than or equal to 2 turn of subsidence was demonstrated in 61% of cases. The overall fusion rate was 91%. In the majority of patients (79%) symptoms were judged to be improved or resolved. Conclusions. The DOC dynamic cervical implant permitted controlled subsidence and prevented progression of kyphotic deformity. There was one construct failure (related to a motor vehicle accident) and an overall fusion rate of 91%. The DOC implant is a safe and effective cervical construct for multilevel spondylotic disease.