Tateru Shiraishi

The authors report on two patients undergoing long-term hemodialysis in whom cervical myelopathy was caused by calcification related to the cervical dural sac. The lesions were demonstrated on plain computerized tomography (CT) scans as dotted curvilinear bands outlining the dural sacs in almost the whole of their cervical spines. During posterior decompressive surgery in both cases, the CT scanning--documented curvilinear bands were identified as calcified plaques infiltrating the fibrous membranes beneath the ligamenta flava, constricting the cervical dural tube. In each case, the spinal cord could not be decompressed by merely enlarging the osseous spinal canal; rather, it required removal of the calcified membrane from the posterior surface of the dura. Based on the operative findings, the lesion should be described as cervical peridural calcification.

To prevent the occurrence of postoperative cervical malalignment, which is often a complication of conventional axial laminectomy or laminoplasty, the authors developed a new double-door laminoplasty procedure in which the C-2 spinal canal is expanded while all the muscular attachments to each split half of the spinous process remain undisturbed. In conjunction with laminoplasties at other levels, this procedure was performed in five patients with ossification of the posterior longitudinal ligament and cervical myelopathy. Neurological improvement was demonstrated in each patient, and there was no radiological evidence of cervical malalignment. The technique for this procedure is described and its usefulness in preventing postoperative spinal malalignment is discussed.

✓ The author describes a new technique for exposure of the cervical spine laminae in which the attachments of the semispinalis cervicis and multifidus muscles to the spinous processes are left untouched. It provides a conservative exposure through which a diverse range of posterior cervical surgeries can be performed. In contrast to conventional cervical approaches, none of the muscular attachments to the spinous processes is compromised. In this paper the author describes the technical details and discusses the applications of the procedure.