We have discussed the development of myelopathy, emphasizing the role of vascular changes, the size of the cervical canal, and the thickness of yellow ligaments.8 Variations exist, particularly in the anteroposterior dimension of the cervical canal, and persons with narrow canals are more likely to develop myelopathy when spondylosis occurs.15,21,22
Haft and Shenkin,10 in reviewing all the results of posterior decompression published to 1963, found that only 42% of the patients had benefited from the operation, but Stoops and King19 found that 83% of their patients showed some improvement. Scoville's operation17 evolved from a simple laminectomy to a more extensive procedure including bilateral facetectomy at one or two levels. His results were gratifying as were those of Aboulker, et al.,1 and Rogers16 who both have advocated extensive unroofing of the entire cervical spine.
Few surgeons have removed ventral ridges by a posterior operation. Mayfield14 described this procedure, which necessitated a wide laminectomy and foraminotomy at multiple levels. Epstein's operation now includes removal of osteophytes by an extradural procedure.5,7
The introduction of anterior disc excision and interbody fusion led Crandall and Batzdorf4 to make a comparative study of patients with myelopathy treated by various surgical procedures. They felt the best results were achieved by the anterior operation. Verbiest and Paz y Guese20 employed their anterolateral operation on patients primarily with single level involvement. In Galera and Tovi's9 series, results of anterior disc excision and fusion were poor. Although Mayfield13 adopted the anterior approach, he could not make a valid comparison with his previous cases.
The experiments of Brieg, et al.,2,3 detailed the biomechanics affecting the spinal cord under normal and pathological conditions, demonstrating that the spinal cord is normally unable to move up and down but adapts itself by plastic deformation. Bone protrusions stretch the cord in ventral flexion so that the major effect in spondylosis is an increase in axial tension as a result of the lateral anchorage through the dentate ligaments.
It appeared from these studies that the matter of the dentate ligaments, long considered a dead issue, might well be revitalized. With this in mind, it seemed worthwhile to consider the value of a combination of extensive cervical laminectomy to effect adequate posterior decompression and section of all the cervical dentate attachments to provide a longitudinal release of the spinal cord.
Keegan JJ: The cause of dissociated motor loss in the upper extremity with cervical spondylosis: a case report. J Neurosurg 23:528–5361965Keegan JJ: The cause of dissociated motor loss in the upper extremity with cervical spondylosis: a case report. J Neurosurg 23:
Rogers L: The treatment of cervical spondylitic myelopathy by mobilisation of the cervical cord into an enlarged spinal canal. J Neurosurg 18:490–4921961Rogers L: The treatment of cervical spondylitic myelopathy by mobilisation of the cervical cord into an enlarged spinal canal. J Neurosurg 18:
This work was presented in part at the meeting of the American Association of Neurological Surgeons, Boston, Massachusetts, April 18, 1972.