Pure tone audiometry is a new method for evaluating congenital malformation of the middle and outer ear (CMMOE)

Background: The preoperative evaluation of Congenital Malformation of the Middle and Outer Ear (CMMOE) is very important. Jahrsdoerfer score commonly used at present, based on CT scanning images of the temporal bone, is often unable to accurately evaluate deformity and hearing level.Aims/Objectives: To investigate and promote a straightforward and easily accessible assessment method, pure tone audiometry, for the evaluation of CMMOE.Material and Methods: A total of 223 cases (244 ears) CMMOE with hearing data were retrospectively analyzed. Among them, 180 cases (197 ears) underwent exploratory tympanoplasty with clear conditions: ossicle numbers in 136 cases (147 ears) and morphology in 128 cases (138 ears) and vestibular window development in 137 cases (146 ears), and CT scans of temporal bone in 113 cases (120 ears). 1). The correlation was analyzed between ossicle numbers, ossicle morphology, Jahrsdoerfer score groups and their corresponding Average Air-Conduction Threshold of pure tone (AACT) at 0.5-4 KHz . 2) The AACT difference is compared among the above groups respectively and between the developed and undeveloped groups of vestibular window at 0.5-4 KHz and each frequency of 0.125-8 KHz. Spearman method was used for correlation analysis (calculating coefficient r and p values). For the data followed a normal distribution, a one-way analysis of variance (ANOVA) and t-test were employed, otherwise, Kruskal Wallis multiple local rank coincidence test and Wilcoxon rank sum test were used. p <0 .05 was considered statistically significant.Results: 1) The correlation coefficients between the groups of ossicle number scores, ossicle morphology scores, Jahrsdoerfer scores and their corresponding AACT are r = -0.187 (p <0 .05), r = -0.073 (p >0 .05) and r = -0.079 (p > 0.05), respectively. 2) Comparison of AACT difference based on ossicle number or morphological scores and Jahrsdoerfer scores with p > 0.05 among all groups, respectively. The AACT difference between the developed and undeveloped vestibular window groups is 5.5 (63.5/69.0) dB HL(p < .05) at 0.5-4KHz, out of 0.125-8 KHz frequency 1, 2, 4 KHz were 5.7 (65.0/70.7) dB HL, 8.4 (60.7/69.1) dB HL and 2 (61.5/63.5) dB HL, respectively, all p < 0.05, the other frequencies with all p > 0.05.Conclusions and Significance: 1) Ossicle number was correlated with AACT, but not for ossicle morphology and Jahrsdoerfer scores. 2) There was no significant difference in AACT corresponding to ossicle number or morphology scores and Jahrsdoerfer scores groups, but the patients with undeveloped vestibular window had poorer hearing than those with developed ones. Therefore, the AACT can evaluate the development of ossicle and vestibular window, and more directly reflect the hearing level than Jahrsdoerfer score. Pure tone audiometry is simple, widely used, and easily accessible, which making it a new assessment method of CMMOE.