Cervical Vertebral Compressive Myelopathy: Diagnosis

Different criteria have been described based on height reduction of the total myelographic contrast column and components of it as tests for compression of the spinal cord due to cervical stenotic myelopathy (CSM). Fifty percent height reduction of the dorsal myelographic column (DMC), <2 mm empiric height of the DMC and a 40% reduction of the ratio of stenosis calculated based on the height reduction of the entire dural diameter (DD) have been described as decision criteria for considering the test result positive. The reasons for selecting these decision criteria or their accuracies have rarely been reported.

A correlation was studied between degenerative spondylolisthesis (DSL) of the cervical spine and spinal-evoked potentials intraoperatively recorded in elderly patients who had surgical treatment for cervical spondylotic myelopathy.

Over a period of 5 years on a central Kentucky Thoroughbred stud farm 132 foals were evaluated for the presence of cervical vertebral malformation (CVM). Lateral cervical vertebral radiographs were obtained on 70 standing foals. These radiographs were evaluated semi-quantitatively and scored numerically for the presence of stenosis of the vertebral canal, enlarged physeal growth plates, caudal extension of the dorsal border of the orifice of the vertebral canal, angular fixation, delayed ossification of bone and degenerative joint disease. From these scores a total CVM score was given for each set of radiographs. All foals were repeatedly examined for clinical signs of neurological disease. Foals with no clinical signs of CVM had maximal total CVM scores (mean +/- sd) of 5.7 +/- 2.8 and foals affected with CVM had maximal total CVM scores of 17.0 +/- 2.8. Determination of the total CVM score was non-invasive, inexpensive and a very accurate procedure for predicting and diagnosing the presence of CVM in Thoroughbred foals up to 1 year of age.