頚椎後方要素を温存した棘突起縦割法の手術成績

Abstract

We studied the clinical and radiological follow-up of patients with double door laminoplasty, splitting the spinous processes, but preserving the posterior supporting structures and using a hydroxyapatite spacer for cervical degenerative diseases. In our hospital standard double door laminoplasty, splitting the spinous processes and using a hydroxyapatite spacer has been performed on 44 patients from July 1994 to September 1995. This standard procedure has gradually produced favorable clinical results. However the partial removal of the spinal posterior structures, as happens in this method, might possibly spoil the stability of the cervical spine. Because of this danger, we incorporated into our standerd method the preservation of the maximum amount of the posterior supporting structures. This modified procedure has been performed on 69 patients since November 1995. Among them, 41 patients who had been followed-up for more than 1 year were selected. Thirty patients had cervical spondylotic myelopathy, 6 had ossification of the posterior longitudinal ligament and 5 had cervical myelopathy due to disc herniation. The average age at operation was 60.0 years old. The average follow-up period was 18.1 months. Preoperative and postoperative clinical assessments were evaluated by Neurosurgical Cervical Spine Scale (NCSS). Radiological courses were examined by the cervical range of motion on the lateral flexion and extension radiographs and the cervical curvature index calculated by Ishihara's method. The improvement of the postoperative clinical courses by NCSS was maintained over 1 year, including cases where the patients were over 70 years old. Radiologically, the cervical range of motion decreased after the operation, but the cervical curvature was generally maintained better after the operation, compared with results obteined by the former standard procedure. We emphasize that double door laminoplasty splitting the spinous processes but preserving the posterior supporting structures is a useful posterior approach, which is easily and safely performed and produces good clinical results for cervical degenerative diseases. However, it should be noted that follow-up periods were short.