Cord diameters and their significance in prognostication and decisions about management of cervical spondylotic myelopathy.

The cases of 35 cervical spondylotic myelopathy patients exhibiting areas of high signal intensity within the cervical cord on T2 and proton density weighted MR images were reviewed. In each case, the ratio of the anteroposterior diameter to the transverse diameter (anteroposterior compression ratio or APCR) at the most compressed segment of the cervical cord was measured on axial MR images and compared with the patient's neurological status. The patients with APCR of 40% or more had a better neurological condition than those with APCR of 38% or less. At the same time, the neurological condition was worse in the patients with APCR of 10% or less than in those with APCR of 15% or more. All patients underwent surgery. The preoperative APCR was compared with the outcomes. The patients with preoperative APCR of 15% or more improved after the operation, but the degree of recovery varied considerably from case to case. The patients with preoperative APCR of 10% or less remained unchanged postoperatively.