Dystopic os odontoideumの1例

A Case with Dystopic Os Odontoideum

I．はじめに

　頭蓋・頸椎移行部の比較的稀な異常の1つに軸椎の歯状突起の遊離奇形os odontoideumがある．Torklusら^10）はos odontoideumをorthotopic osとdystopicosの二型に分類している．すなわちorthotopic osはレ線上，正常の軸椎歯突起の位置にあり，dystopic osは，レ線上，斜台の近くに位置し，ときには斜台に癒合している．

　また，os odontoideumを有する例の神経症状発現の機構としては，atlanto-axial dislocationが重視されている^4,5），その手術法に関しては，長島^5）が述べるように1）immobilization，2）fusion，3）decompression，4）decompressionおよびfusion，の4種類のいずれかが症例により選択されている．

A 37 year old male with dystopic os odontoideum fused to the clivus is reported.

He had felt the weakness of lower extremities since about 20 years before, especially when walking a long way or standing with some heavy things. At about 8: pm on 21st April 1978, he fell down at the front door after taking sake. He lost his consciousness and was admitted to the local hospital. At about 6 : 00 am 22nd April 1978, he became alert but the weakness of his upper and lower extremities was noted. On 24th Apail 1978, he became tetraparetic. Early in May 1978, he had an episode of dyspnea and then the hoarsness of voice was appeared.