早期に発見された聴神経鞘腫10例の検討—脳神経外科医の立場から

A Clinical Analysis of Ten Cases of Small Acoustic Neurinomas

I．はじめに

　近年聴神経鞘腫はその診断法の向上により腫瘍が小さな段階で発見され，重篤な臨床症状を呈する以前に摘出できる症例が増加している^1,2）。またそれに伴い顔面神経麻痺などの術後合併症の発生頻度も従来に比して減少し，さらに聴力機能の温存にも注意が払われるようになってきている。当教室ではこれまでに140例の聴神経鞘腫を経験したが，その中で最大径2cm以下で比較的早期に発見されたと思われる症例が10例あった。その臨床検査所見，手術治療成績などにつき若干の文献的考察を加えて報告する。

　Ten cases with acoustic neurinoma in its early stage were reported. The size of tumors was within 2cm in maximum diameter, and the neurological findings in all cases were only disturbance of the 8th nerve.

　Auditory brainstem response showed abnormal findings in all cases ; no response in one case, only I wave in two, I and II wave in one, and the prolongation of I - V interval in 6 cases.

　The tumors of all cases could be detected by contrast-enhanced CT scan ; in 6 cases homogeneous enhancement was observed, in two ring enhancement, in one multicystic mass and in one irregular enhancement.

　Nine cases were operated by suboccipital approach and their tumors could be removed totally. Anatomical preservation of the facial nerve was obtained in 8 cases (88.9%) and that of the acoustic nerve in 8 cases (88. 9%). Functional preservation of the 7th nerve was observed in 4 cases and in two out of the remaining 4 cases the facial nerve function was improved. The hearing level was preserved in one case and improved slightly in postoperative course.