Clinicoradiologic study of cervical laminoplasty with posterolateral fusion or bone graft

Study Design. A retrospective study of cervical expansive laminoplasty for cervical myelopathy from a clinico-radiologic perspective. Objective. To clarify the correlation among sagittal curvature of the cervi cal spine, cervical range of motion, sagittal plane translation, spinal cor d atrophy, and myelopathic symptoms in patients who have undergone laminopl asty. Summary of Background Data. Laminoplasties were developed to diminish thr u ndesirable effects of laminectomy, which include postoperative kyphothic ch anges and instability. However, the superiority of laminoplasty over lamine ctomy remains controversial. Methods. Fifty-one patients with cervical spondylotic myelopathy or ossific ation of the cervical posterior, longitudinal ligament who underwent lamino plasty were radiologically assessed before and after surgery. The index of the sagittal curvature, intervertebral range of motion, site of maximal com pression were measured to evaluate interrelations among those parameters an d myelopathic symptoms. Results. There were no patients with kyphotic curvature before surgery. The postoperative curvature tended to be less lordotic. This tendency did not adversely affect postoperative symptoms. The intervertebral range of motion was significantly decreased except at C1-C2. The final C4-C5 range of moti on and the postoperative myelopathic symptoms were negatively correlated. A significant correlation was observed between the postoperative spinal cord atrophy and the final myelopathic symptoms. Conclusions. The decrease in the lordotic curvature index and the decrease in the intervertebral range of motion after laminoplasty did not cause neur ologic deterioration. In the C4-C5 intervertebral segment with a high incid ence of listhesis, the restriction of the C4-C5 range of motion improved th e clinical myelopathic symptoms. The radiologic prognostic factors were the postoperative restriction of intervertebral range of motion in preoperativ ely unstable segments and the anatomic reversibility of spinal cord insult.