Degenerative disc disease (DDD) of the cervical spine is a common condition that causes significant pain and disability. Treatment for DDD in 2000 exceeded 110,000 patients in the United States alone [1]. A common treatment option for patients involves removal of the degenerated disc and fusion of the adjacent vertebral bodies. However, previous research has shown that as many as 25–92% of patients treated with fusion have disc degeneration at the adjacent levels within 10 years after surgery [2,3]. It has been hypothesized that this is the result of a change in adjacent vertebral segment motion [4]. However, it is unknown if spinal fusion alters motion at these segments. Thus, the objective of this study was to compare the dynamic, three-dimensional (3D) motion of the cervical spine in normal control subjects and spinal fusion patients.
Continuous cervical spine kinematics during in vivo dynamic flexion-extension