CERVICAL SPONDYLOTIC STENOSIS AND MYELOPATHY - EVALUATION WITH COMPUTED TOMOGRAPHIC MYELOGRAPHY

Objective: To determine which components of cervical spondylosis are m ost frequently present in patients with myelopathy. Design: We reviewe d the findings in 93 patients who underwent surgical decompression for cervical spondylotic myelopathy between January 1986 and December 198 9 at Mayo Clinic Rochester. Material and Methods: All 93 patients (72 men and 21 women) underwent computed tomographic (CT) myelography. In addition, magnetic resonance imaging scans were available in 25 patien ts, and plain CT scans were obtained in 2. Results: A review of CT mye lograms revealed that all neurocompressive intraspinal spondylotic cha nges were reflected in the shape of the spinal cord. Among the 93 pati ents with myelopathy, the configuration of the spinal cord could be ca tegorized into primarily three dominant types: A (severe encroachment that compressed the cord into the shape of a banana; N = 40), B (moder ate encroachment that produced less prominent compression; N = 23), an d C (moderate bilateral uncovertebral spurs; N = 12). As a comparison group, 30 patients with similar spinal cord deformities but without pr ogressive myelopathy were analyzed. Correlation of the two groups show ed that myelopathy was present in up to 98% of patients with type A sp inal cord, in 75% with type B,and in 71% with type C. The findings on magnetic resonance imaging were similar to those on CT myelography, bu t the bony spondylotic components were less readily seen. Conclusion: The precise pathophysiologic mechanism of myelopathy in spondylosis re mains an enigma. Although the bulk of the data on our patients support s direct compression, we believe that the cause is multifactorial.