cervical myelopathy treatmentdegenerative cervical myelopathycervical compressive myelopathycervical stenosis with myelopathytraumatic cervical myelopathyprogressive cervical myelopathysevere cervical myelopathymyelopathy surgerydefine cervical myelopathyhoffman sign cervical myelopathycervical spine myelopathyacute cervical myelopathy