To investigate and define the clinical results and prognostic factors affecting surgical outcome of the various etiologies of a cervical myelopathy.

Forty-one cervical myelopathy patients, who underwent surgery from March 1997 to March 2004, were retrospectively reviewed. The patients were divided into three groups according to the cause, HIVD (10 cases, group A), OPLL (14 cases, group B), cervical spondylotic myelopathy (17 cases, group C). An anterior cervical discectomy and fusion was carried out on one or two segments in group A, and an expansive open-door laminoplasty was performed in groups B and C. The correlations between age, onset, preoperative JOA score, signal change in the cord on the T2 weighted image MRI, compression ratio, which are known etiologies of myelopathy, and the recovery rate according to causes were analyzed.

The mean preoperative and postoperative JOA score was 11.2 and 14.6 respectively. The mean recovery rate was 61.7%. There was no significant difference in the preoperative JOA score in each group (11.40 in group A, 11.93 in group B, 10.53 in group C). The recovery rate was ranked as follows: group A, B, and C (group A 75.98%, group B 61.39%, group C 53.61%) but the difference was not significant. Age, preoperative JOA score, signal change on T2WI MRI in group A (p<0.05), age, preoperative JOA score in group B (p<0.05), age, preoperative JOA score, signal change on T2WI MRI, compression ratio in group C (p<0.05) were significant prognostic factors that influenced the recovery rate.

There was no difference between the preoperative clinical symptoms and the surgical outcome according to the cause. The most significant prognostic factors affecting the results of surgery for cervical myelopathy were age, preoperative JOA score in each group. A specific prognostic factor in each group may exist, but a further evaluation is needed.