Rupture of Inner Ear Window（内耳窓破裂症）とその一手術例

RUPTURE OF INNER EAR WINDOW, A CASE REPORT

　Otomicrosurgeryの発達に伴い鼓室内を観察する機会が増えたため，頭部外傷，爆発事故，耳硬化症の手術後に人工的アブミ骨が外れた症例などに^1）前庭窓（卵円窓），蝸牛窓（正円窓）が破れて外リンパが漏出し，難聴，耳鳴，めまい，平衡失調などの症状を来たすことが時々報告されていた。1968年Simmons^2）はネコの正円窓を破つた後，電気生理学的に聴力の推移を調べた実験結果^3）4）に基づいて，臨床的にも突発性難聴症例中には両窓の穿孔による発症例があると考え，このような15症例とともにこれをtheory of membrane breaksと称して発表したが，手術的に穿孔を確認しなかつた。同年Fee^5）は始めて頭部外傷後の3難聴例の鼓室を手術的に観察し，卵円窓の穿孔を閉鎖した所，感音難聴，めまいが著明に改善したことと，卵円窓瘻孔と内耳骨折による外リンパ瘻の鑑別についてのべた。ついで1970年Stroudら^6）は特発性にも卵円窓穿孔があることを，Goodhill^7）は突発性難聴患者に手術を行ない，正円窓穿孔が原因となつているものがあることを報告した。始めは本症の主症状は難聴と思われていたがHealyら^8）9）はめまいも主症状であることを20例の報告とともに強調した。

　以来欧米では報告が相ついでいる一方，わが国においては漸く最近本症症例の紹介^10）や報告^11）が現われたが，まだ詳しい解説はなく手術により本症と確かめられた症例の報告もない。

　A man, aged 26, was suddenly attacked by deafnes and tinnitus accompanied by severe vertigo when he had closed the door of his car with a bang. A right tympanotomy performed after six day of the accident revealed accumulation of transparent fluid in the tympanum and round-shape perforations of the round window membrane. The perforations were found to be already closed with a thin membrane without the leakage of the perilymph. Following the operation the deafness failed to be improved but the vertigo gradually disappeared.

　So far, 75 ears of 73 patients who suffered rupture of the inner ear window were ascertained by operations ; these were reported in the literature. In order to clarify the clinical features of these cases clinical analysis are made : Deafness (95%) is more common than vertigo (71%). Differential diagnosis of these conditions from sudden deafness, Ménière's disease and benign paroxysmal positional vertigo is important. Association of the rupture of round window with head injury and barotrauma should be taken into consideration. Operative closure of the ruptured membrane appeared to be more effective in alleviating vertigo (93%) than deafness (20%). In our opinion the exploratory tympanotomy could be delayed for 2 or 3 weeks after onset of the symptoms, but it should be positively performed to close the perforation.