小脳橋角部腫瘍におけるblink reflexの検討

INVESTIGATION OF BLINK REFLEXES IN CEREBELLO-PONTINE ANGLE TUMORS

　抄録　小脳橋角部腫瘍28例（聴神経鞘腫22例，髄膜腫6例）および副神経—顔面神経吻合物術を施行した上記対象28例中の7例を含む13例にblinx reflexの検索を有ない次の結果を得た。1）聴神経鞘腫ではR1の異常を20例（91％），R2の異常を11例（50％）に認めた。早期診断にはR1潜時の左右差から潜時遅延の有無を判定有ることが重要である。充実性腫瘍群では大きな腫瘍ほどR1潜時が遅延傾向にあったが，腫瘍内出血群や嚢腫性腫瘍ではいずれも高度の異常を示すものが多かった。2）髄膜腫ではR1異常を5例に認めたが，巨大な腫瘍が多いにもかかわらず，R1異常の程度は聴神経鞘腫に比較し軽微な傾向にあった。3）副神経—顔面神経吻合術後の検索では，1例を除く全例に短潜時のR1類似反応を認め，R2類似反応は1例のみに認められた。4） blink reflexは小脳橋角部腫瘍の早期診断や手術前後にわたる三叉・顔面神経，脳幹の機能障害程度の把握に有用な検査法である。

Blink reflexes were analysed in 28 cases with cerebello-pontine angle tumors (22 cases of acoustic neurinoma and 6 cases of meningioma).

In patients with acoustic neurinoma, delay or absence of R1 was found in all but two cases (91 %) and abnormality of R2 was in 11 (50%). Estimating the mean latency difference of R1 on both sides it was found useful for establishing early diagnosis of small acoustic neurinomas, which had no apparent clinical signs of facial or trigeminal nerve involvement. In patient with obsolete hemor-rhage (5 cases) or large cyst (6 cases) within the acoustic neurinomas, which were proven at opera-tion, abnormality of blink reflexes was more pro-minent than in patient with solid tumors (11 cases).

In patients with meningioma, although all were huge tumors, abnormality of R1 was less conspi-cuous in comparison with acoustic neurinoma. Bilateral delay of R2 was found in 3 of 6 patients.

In 13 patients who underwent spinal accessory-facial anastomosis for facial palsy after removal of the tumors, R1-like response were recorded in all but one on the affected side and R2-like re-sponse was recorded in only one patient.

Observing alteration of blink reflexes in patients with cerebello-pontine angle tumor was useful for establishing early diagnosis and evaluating func-tion of trigeminal nerve, facial nerve and brain-stem.