[EFFECT OF ANTERIOR CERVICAL SPINAL CORD COMPRESSION FACTOR IN TREATMENT OF CERVICAL SPONDYLOTIC MYELOPATHY].

To observe the effectiveness of posterior cervical laminoplasty, and to determine the significance of the classification of spinal cord compression of multi-level cervical spondylotic myelopathy (CSM).The clinical data were analyzed from 1 216 cases of multi-level CSM undergoing posterior cervical laminoplasty between February 1998 and February 2013. The patients were divided into 4 groups: soft anterior spinal cord compression and light canal occupation (<50%) in 569 cases (46.8%, group A), soft anterior spinal cord compression and heavy canal occupation (≥ 50%) in 365 cases (30.0%, group B), bony anterior spinal cord compression and light canal occupation in 210 cases (17.3%, group C), and bony anterior spinal cord compression and heavy canal occupation in 72 cases (5.9%, group D). There was no significant difference in gender, age, disease duration, lesion level, and complications among 4 groups (P>0.05). Because of different levels of spinal cord compression, there were significant differences in visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score among 4 groups (P<0.05).Cerebrospinal fluid leakage occurred in 9 cases (2 cases in group A, 1 case in group B, 3 cases in group C, and 3 cases in group D), and was cured after symptomatical treatment. There was no postoperative complication of wound infection, lamina re-closing, or C5 nerve root paralysis in 4 groups. The follow-up time ranged from 24 to 74 months (mean, 35 months). In group D, 17 patients (23.6%) had deteriorated symptom at 6-12 months after operation, and good recovery was achieved in the patients of the other 3 groups. At last follow-up, the JOA score and VAS score were significantly improved when compared with the preoperative scores in 4 groups (P<0.05); the JOA score, improvement rate, and VAS score of group D were significantly lower than those of groups A, B, and C (P<0.05), but there was no significant difference among groups A, B, and C (P>0.05).In the multi-level CSM, the anterior compression of the spinal cord should be classified, this has a guiding significance for the prognosis of CSM and the choice of surgical method.