The Study Of Magnetic Resonance Imaging Diagnosis And Surgical Treatment For Patients With Juvenile Cervical Flexion Myelopathy

Objective To investigate the sensitivity and specificity of magnetic resonance imaging in the diagnosis of juvenile cervical flexion myelopathy(CFM).To investigate the pathophysiology of CFM,and to examine an optimal surgical treatment.Methods 1)The neutral-position and flexion-position cervical MRI of 23 patients and 22 control subjects were evaluated.The difference in frequency of these findings between the control and patient groups was examined by means of theχ2test.The sensitivity,specificity,positive predictive value,and negative predictive value of these MR imaging findings in the diagnosis of Hirayama disease were calculated.Multiple logistic regression was performed to explore the relationship with CFM. 2)The authors performed surgery treatments in 9 CFM patients.5 patients underwent anterior decompression and fusion in which autogenous iliac bone graft was placed. The other 4 patients underwent posterior fusion of five laminae with duroplasty.All patients were diagnosed preoperatively,and confirmed in the progress stage through assessment of symptoms.The clinical and radiographic characteristics of them were examined before and after surgery to evaluate the surgical results.Results 1)Among the neutral-position MR imaging findings,there was a significant difference in the frequency of localized lower cervical cord atrophy,asymmetric cord flattening,and LOA between the control and patient groups(P<0.05).After multivariate analysis,LOA was the only significantly important predictor of the disease,with odds ratio of 46.78(95%CI3.45-634.41 )。2)Among the flexion-position MR imaging findings,There was a significant difference in the frequency of localized lower cervical cord atrophy,asymmetric cord flattening,forward displacement of the cervical dural sac,flow void in the posterior epidural space between the control and patient groups(P<0.05).After multivariate analysis,they were all significantly important predictor of the disease.3) The C6-level cervical spinal cord AP diameter in neutral-position(Dn) and flexion-position(Df) of patients were significantly smaller than control groups(P<0.01).The reduction of AP diameter in flexion was more significant in patients than that in control groups(P<0.01).4) The mean follow-up period was 11.1 months(range 7-23 months).limitation of digitorum extension was improved in 3 patients in the first 3 days postoperatively.At the final follow-up examination,symptom progression was stopped in all patients,muscle strength was improved in seven,and sensory disturbance was alleviated in 2 patients.However, Intrinsic muscle atrophy,which was evident in nine patients preoperatively,improved in only one.In the 3 cases whose MRI has been reviewed we observed that the localized lower cervical cord atrophy,asymmetric cord flattening,forward displacement of the cervical dural sac,flow void in the posterior epidural space in the original disappeared.However,T2 high signal changes in spinal cord still exists.Conclusion 1)Hirayama disease included in the juvenile cervical flexion myelopathy.LOA from posterior dural sac and subjacent lamina at neutral-position MRI is a valuable finding in the early diagnosis of Hirayama disease.Flexion-position MRI can reveal the dynamic changes of spinal cord and dural sac,which is more valuable to diagnose CFM.2)Decompresive and fusion procedure is performed in both two approch.Anterior approch allows direct removal of diseased anterior structures,posterior approch allows mitigation of the constricted dura mater.Because same neurological and radiological improvement was seen in patients underwent different surgery,it is believed that both anterior and posterior approach surgery are effective treatment for patients with cervical flexion myelopathy.