アブミ骨手術症例の術前後のtympanogramの意義

CLINICAL EVALUATION OF TYMPANOMETRY IN CONDUCTIVE DEAFNESS TREATED WITH STAPES SURGERY

　I．緒言

　Tympanometryの歴史は1946年Metzによる中耳伝音系の音響impedanceの測定にはじまる^1）。その後多くの研究報告がなされているが，測定装置については初期の頃の各研究者個々の試作的装置^2）3）から，最近になつて2,3の型式のものが製品として広く市販されるようになつた。そのために検査そのものはきわめて容易となつたがその一方では臨床dataの集積につれて本検査法の診断的価値について若干の異論が出ている様にも思われる^4）5）。

　われわれは今回，本検査法の臨床的価値を検討するために，鼓膜穿孔を伴わない各種の伝音難聴症例を対象として，術前検査所見と手術所見の対比，術後の検査所見とstapedectomyを中心とした手術成績の対比を行ない，術前後の本検査成績を比較検討してみた。その結果から本検査法の診断的価値を明らかにしようと試みたのでその結果を報告する。

　Tympanograms in 6 cases of conductive deafness with normal tympanic membrane were recorded with Grason-Stadler's Otoadmittancemeter before and after stapes surgery. The pre-and postoperative tympanograms were studied compairing the surgical findings and results of hearing recovery.

　In four cases including 2 cases of otosclerosis, a case of stapes fracture and a case of congenital stapes fixation, the tympanometric diagnosis before and after the surgery was well consistent with the surgical findings and results. In these cases, the pathological tympanograms returned into the normal type.

　In the case of otosclerosis whose tympanogram showed a type of tympanic scar, a notch which was observed on the preoperative tympanogram became shallow after the successfull stapedectomy.

　In the other case of otosclerosis in whom bone conduction hearing was deteriorated after the surgery, the preoperative tympanogram showed normal type.

　In general, it is concluded that tympanometry can satisfactorily demonstrate the pathological conditions in the conductive system, and it can be a usefull clinical examination before and after the surgery.