游离齿突小骨的临床和MRI表现特征

The Clincal Findings and MRI Features of Os Odontoideum

目的探讨游离齿突小骨(Os O)MRI表现特征。方法搜集武汉同济医院2010年1月至2014年7月间20例Os O患者MRI资料,回顾性分析Os O的MRI表现特点。结果 20例中,MRI显示Os O错位17例(85.5%),寰枢关节不稳20例(100%),后弓前移14例(70.0%),齿突基底部移位19例(95.0%),其中齿突基底部后移18例(90.0%),椎管骨性狭窄20例(100%),脊髓受压变细19例(95.0%),脊髓变性19例(95.0%),合并先天颈部畸形20例(100%)。结论 MRI发现枢椎齿突基底部前上方发育不良且有完整骨皮质的小骨,可考虑作出Os O诊断。

Objective Os odontoideum （OsO）is a rare but it may present with atlantoaxial instability , spinal canal stenosis and myelopathy. To analyze the clinical and MRI of os odontoideum retrospectively, so that to improve the diagnosis and differential diagnosis of OsO. Methods 20 cases of os odontoideum were reviewed in Tongji Hospital between the years 2009 to 2014. MRI of cervical spine were performed to verify OsO. Results MRI showed that the malposition ossi- cles were 85.5% , C2 odontoid base displacement were 95.0% , spinal canal stenosis 100% , anterior displacement of C1 posterior arch 70.0% % , C1/2 joint instability 100% , compression of the spinal cord 95.0% and myelopathy 95.0%, with congenital cervical deformities 100%. Conclusion OsO can be diagnosed by MRI, if it find out the malposition ossicles with surrounding complete bone cortex above C2 odontoid base, often with atlantoaxial dislocation ,spinal canal steno- sis,compression and atrophy of the spinal cord with myelopathyo MRI showed that the C2 odontoid base displacement ,the anterior displacement of C1 posterior arch were the main causes of spinal canal stenosis, often with compression of the spinal cord and/or myelopathy .