title: Evaluation of the Carhart effect in congenital middle ear malformation with both an intact external ear canal and a mobile stapes footplate.
abstract: The medical charts of 41 ears with congenital middle ear malformation with both an intact external ear canal and a mobile stapes footplate were reviewed retrospectively to study the Carhart effect. The operations were categorized as successful or unsuccessful according to the extent of decrease in the average air-bone gap. Statistically significant differences were observed between the 2 groups with respect to the changes in pure-tone average and the changes in the bone conduction (BC) threshold at 1 and 2 kHz. Linear regression analysis revealed weak correlations between the change in the BC threshold and the postoperative BC threshold at an overall level and at the 4 frequencies tested. Stapes ankylosis is a main cause of the Carhart effect. The present study showed that in congenital middle ear malformation, the Carhart effect was caused not only by stapes ankylosis but also by other types of disruption in the ossicular chain.
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, Faculty of Medicine, University of Tokyo, Tokyo, Japan. tsakamoto-tky@umin.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Akinobu
authors.initials: A
authors.lastname: Kakigi
authors.forename: Akinori
authors.initials: A
authors.lastname: Kashio
authors.forename: Kaori
authors.initials: K
authors.lastname: Kanaya
authors.forename: Mitsuya
authors.initials: M
authors.lastname: Suzuki
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamasoba
mesh_terms: D000293:Adolescent; D000328:Adult; D000844:Ankylosis / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D001309:Auditory Threshold / Q000502:physiology; D001844:Bone Conduction / Q000502:physiology; D002648:Child; D004424:Ear Canal; D004432:Ear, Middle / Q000002:abnormalities* / Q000601:surgery*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013199:Stapes / Q000002:abnormalities* / Q000502:physiology; D013200:Stapes Mobilization; D016896:Treatment Outcome; D055815:Young Adult