Prevalence of middle ear malformation and outcomes of tympanoplasty and/or canalplasty in patients with and without congenital external auditory canal stenosis

Abstract

ObjectiveTo compare the prevalence of middle ear malformations between patients with and without congenital external auditory canal stenosis (CEACS) and to investigate the outcomes of tympanoplasty and/or canalplasty in terms of tympanic membrane (TM) size and external auditory canal (EAC) stenosis in patients with middle ear malformation. MethodsTwenty-five patients who underwent primary tympanoplasty and/or canalplasty for middle ear malformation at a tertiary academic medical center were retrospectively reviewed. CEACS was defined as an EAC diameter of 4 mm or less. Intraoperative findings, including irregularity of the ossicles, facial nerve, or chorda tympani; size of the TM and EAC on computed tomography; and pre- and postoperative hearing level, were collected. ResultsWe included 7 and 18 patients with and without CEACS, respectively. The malleus handle defect, anterior deviation of the chorda tympani, and small TM (≤7 mm) (p-values 0.015, <0.001, and 0.003, respectively; Fisher's exact test) had significantly higher prevalence in patients with CEACS than in those without. The mean postoperative air-bone gap (ABG) in patients with CEACS was not significantly different from that in patients with normal-sized EAC (20.6 dB and 19.5 dB, respectively; p-value, 0.121; Mann–Whitney U test). No difference was observed in mean postoperative ABG between patients with small TM and those with normal-sized TM (19.2 dB and 20.0 dB, respectively; p-value, 0.469; Mann–Whitney U test). ConclusionPatients with CEACS were more likely to have malleus handle defect, anterior deviation of the chorda tympani, and small TM than those without CEACS. Hearing outcome of patients with CEACS and a malformed malleus and/or incus might be equivalent to that of patients without CEACS following tympanoplasty and/or canalplasty, regardless of the EAC or TM size.