In the past decade, MR imaging has been widely used in the diagnosis of spinal disorders. MRI is very sensitive in detecting disc abnormalities and demonstrating pathologic condition of spinal cord. In compressive cervical myelopathy such as
cervical
spondylotic myelopathy and ossification of posterior longitudinal ligament. The etiology of symptoms and signs is probably multifactorial. However. A basic and treatable factor is mechanical cord compression. Therefore. It is essential to
recognize
cord
morphology and it's relationship to surrounding structures to determine surgical treatment. In this study. we tried to recognize the value of MRI in the management of cervical myelopathy by comparing the findings on pre and postoperative MRI to
the
clinical symptoms.
This clinical study included patients with cervical myelopathy treated surgically. 22 patients with CSM and 10 with OPLL. All patients underwent pre and postop. MRI studies. Seventeen patients underwent laminoplasty alone, and 3 underwent
anterior
fusion alone. Simultaneous laminoplasty and anterior fusion were performed in 12. Ia cases which cervical lordosis was maintained, posterior migration of the cord after 4-level laminoplasty averaged 3.1 mm and 5.3 mm after 5-level laminoplasty.
In
the
presence of a kyphotic curve. Laminoplasty resulted in some degree of expansion of the dural tube without posterior migration of the cord and little symptomatic improvement. The pre and post op. A-P compression ratios of the cord were not always
in
accordance with severity of symptoms. But did show a proportional tendency.
An area of intramedullary high signal intensity was observed at the site of maximal cord compression on T2 MRI in 11 CSM(50.0%), 3 OPLL(33.3%) patients. These 14 patients were classified into two groups.
In group 1, 7 patients, the high signal intensity areas which showed on T2 MRI were not enhanced by Gadolinium injection, However, In group II, another 7 patients, the high signal intensity areas were enhanced.
The mean post operative recovery rate was 73.6±22.6% in patients who had no signal intensity area on T2 MRI, 71.3±18.8% in group I, 58.1±15.1% in group II.
The presence of a high signal intensity area was correlated with the severity of myelopathy and the surgical recovery was least favorable in group II. But there was no statistical significance.
In conclusion, MRI is though to be a valuable means for diagnosing cervical myelopathy and appeared to be essential to recognize the altered relationship of the cord and its surrounding structures after operation.
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