中耳根治手術の術後聽力に及ぼす影響に就いて

緒言

　中耳根治手術が術后の聽力に及ぼす影響に就いては，Grunert（1896），Stacke（1899），Grossmann（1901），Siebenmann ＆ Oppikofer（1902）等．以来幾多の報告があるが，それ等の成績は根治手術の影響必ずしも一定でなく，手術により聽力の好転する場合と反対に悪化する場合，即ち同じ手術によつて相反する結果を生する事を示している．勿論手術によつて聽力に殆んど変化が与えられなかつた症例をも見る．斯くの如く根治手術が如何なる結果を生ずるかを検討する事は根治手術の施行に当つて重要なる事と考える．私は根治手術の28例の患者に就いて他の目的のためにAuoliometerによる聽力検査を行つたゝめ用いた振動数は限られた範囲のものであるが，その範囲に於て如上の見地から検討を加えて次の如き結果を得たので報告する．

　MARUYAMA attempts to find the amount of hearing losses incurred when radical mastoidectomy is performed for treatment of chronic otitis media by use of audiometer within range of 200 to 3200 cyeles. Twenty patients (20 ears) are examined in this way; the results are as follows;

　When preoperative hearing loss was less than 20 db post-operative loss would have been increased but, if the former were more than_30 db to start with there would be improvement of hearing after the operation. Generally speaking the ears whose hearing losses registering up to 60 db may either show increased or decreased hearing as result of operation but, there was a tendency in either cases to approach the median which ranged from 20 to 40 db losses.