上段颈髓减压效果MR评估标准的探讨

A study of MR evaluation criterion for decompression effect on the upper cervical cord

目的探讨寰枢关节脱位伴上段颈髓受压和减压的形态学及MR矢径变化特点,建立上段颈髓减压效果的MR评估标准。方法通过观察和测量20例正常及25例寰枢关节脱位的上段颈髓受压及减压的MR矢径变化规律,设计出上段颈髓受压指数公式和上段颈髓减压改善率公式。结果上段颈髓受压指数=(拟正常颈髓矢径-最窄段颈髓矢径)/拟正常颈髓矢径；颈髓减压改善率=(治疗后最窄段矢径-治疗前最窄段矢径)/(拟正常颈髓矢径-治疗前最窄段矢径)×100%。结论上述MR评估标准能客观评估上段颈髓受压程度和减压改善效果。

Objective To explore the morphological features and changes in the MR sagittal diameter when atlanto-axial dislocation with ventral spinal cord compression is treated by ventral decompression so as to establish radiological evaluation criteria for the decompression effect on the upper cervical cord. Methods The MR sagittal diameters of the upper cervical cord in 20 normal persons and 25 patients with atlanto-axial dislocation with ventral compression were measured. The formulas of compression exponent of upper cervical cord （CEUCC） and of the compression improvement rate of upper cervical cord （CIRUCC） were designed. Results The formulas are as follows： CEUCC = （PSDCC - SDSCC）/PSDCC. PSDCC means the pseud-normal sagittal diameter of cervical cord. SDSCC means the sagittal diameter of the most stegnotic segment of cervical cord, CIRUCC = （postoperative SDSCC - preoperative SDSCC） / （PSDCC - preoperative SDSCC） . Conclusion The above-mentioned radiological evaluation criteria can objectively assess the compression and the compression improvement effect on the upper cervical cord.