The Comparison Between the Stand-alone Cage and the Autologous Iliac Bone Graft/Anterior Plating in the Single-level Surgical Treatment of the Cervical Spine

Inclusion Criteria: * Single level degenerative cervical spine disease * aged 30 - 70 * no improvement of symptom for 8 weeks of non-surgical treatment. * degeneration in other levels without stenosis, accepted Exclusion Criteria: * osteoporosis * disease with poor bone quality * Cancer * Previous cervical spine surgery * Multiple levels disease * Ossification of posterior longitudinal ligament * Kyphosis at the index level * Developmental stenosis (diameter of C7 spinal canal \< 10mm)