種々の骨奇形を合併し，整復が不可能であり，mandible and tongue-splitting approachを行ったatlanto-axial dislocationの1例

A Mandible and Tongue-splitting Approach for an Anterior Decompression at C1/2 Level for Irreducible Atlantoaxial Dislocation due to Multiple Congenital Anomalies of the Craniovertebral Junction

Ⅰ．はじめに

　環軸関節脱臼（atlanto-axial dislocation）の多くは整復が可能であり，手術的治療法としては，前方あるいは後方よりの固定術が広く行われている．

　しかし，種々の要因により整復不能な場合には，手術的治療法は困難なことが多く，これまでの文献を見ても，整復不能な環軸関節脱臼の治験の報告は比較的少ない^{3,4,9,16,17,20,23）}．この場合脊椎管はC_1-2のlevelで非常に狭くなり，慢性の圧迫のため脊髄は著明な萎縮に陥っていることが多い．

A 20 year-old man having toricollis since his youth had been in good health until 3 months before admission when he noted weakness of his lower limbs, following a heavy labor which he had taken for about 1 month. About 2 weeks before admission, there occurred progressing numbness and weakness of the upper limbs. His gait became unstable. There was no sphincter disturbance.

Examination: The neck was short with lower setting of the hair line. His head was tilted to the left side. Horizontal nystagmus was noted at left lateral gaze. His soft palate movement was poor. There was spastic paralysis of all the limbs.