SPINAL-CORD EXPANSION AFTER DECOMPRESSION IN CERVICAL MYELOPATHY - INVESTIGATION BY COMPUTED-TOMOGRAPHY MYELOGRAPHY AND ULTRASONOGRAPHY

Study Design. This study analyzed anatomic characteristics of 44 patie nts with cervical myelopathy. Objectives. This study was conducted to clarify the patterns of spinal cord expansion after decompression, the ir relationship to clinical recovery, and the capacity of the compress ed spinal cord for restoration. Summary of Background Data. No previou s studies have clearly assessed the relationship between morphological changes of the spinal cord and clinical improvement after posterior d ecompression in patients with cervical myelopathy using computerized t omography myelography and intraoperative spinal sonography. Methods. F orty-four patients with cervical myelopathy underwent posterior decomp ression. The diagnosis was cervical spondylosis in 26 patients and oss ification of the posterior longitudinal ligament in 18 patients. The c ross-sectional area, sagittal diameter, and frontal diameter of the sp inal cord at the level of maximum compression were determined by compu terized tomography myelography (performed before and 1 month after dec ompression) and by intraoperative spinal sonography. Results. Expansio n of the spinal cord was defined as immediate or gradual. Of the 44 pa tients, 20 demonstrated gradual expansion, and their clinical recovery rate was 68.4%. In contrast, the clinical recovery rate of patients w ithout gradual expansion was only 32.6%. Good clinical recovery was si gnificantly related to gradual expansion. The patients were divided in to four groups (A-D) based on the clinical recovery rate and compressi on ratio. Group A (severe compression and poor clinical recovery) show ed a significantly smaller cross-sectional area of the spinal cord tha n Group D (severe compression, but good clinical recovery). Conclusion s. Preservation of the cross-sectional area of the spinal cord, even w hen it is severely compressed and deformed, is an important factor in a good surgical outcome.