小脳橋角腫瘍の進展方向に関する神経耳科学的考察

NEUROTOLOGICAL CONSIDERATIONS UPON THE PATH OF PROGRESS WHICH CEREBELLO-PONTINE ANGLE TUMOR TAKES

　Ⅰ．緒言

　聴覚および前庭平衡機能検査は，単に内耳機能の観察にとどまることなく，中枢路を含む広範囲の神経耳科学的領域を監視すべきものである。とくに第Ⅷ神経は神経耳科医にとつて，最も関心の深い領域であり，検査結果より当神経に対する病的侵襲が末梢迷路側より発展したものか，あるいは脳幹側より進展したものかを知ることができるならば，きわめて興味深いことである。最近われわれは，聴神経腫瘍症状を呈する興味ある松果体腫瘍の1例を経験したので，聴覚検査，前庭平衡機能検査および聴器X線検査などの耳科学的検査成績を中心にこの問題について考察を行なつてみた。

　The Pontine angle tumor which effects the eighth nerve has two different sources of origin; one, starting from the internal auditory meatus and spreading towards the angle and the other, starting from the angle and spread towards the internal auditory meatus. To neurotologist it seems the most interesting thing to determine the mode in which this tumor may spread.

　In the present case a giant acoustic tumor was at first suspected from the results of puretone audiometry, vestibular functional tests and x-ray examination of the internal auditory meatus. But, because of the absence of facial nerve involvement and the presence of residual hearing the tumor was considered as being originated from the brainstem and spreading towards the internal auditory meatus. That this latter assumption being as correct was proven by observations made later by surgical inter-Vention.