Diagnostic Value Of Pure Tone Audiometry On Ossicular Chain Status Of Chronic Otitis Media

Objective: To analyse the influence of ossicular pathology on hearing loss and the diagnostic value of pure tone audiometry on ossicular chain status of chronic otitis media.Methods: Restrospective data was collected on 166 patients(168 ears)with chronic suppurative otitis media(CSOM)or middle ear cholesteatoma(CHOLE)undergoing their first tympanomastoidectomy performed by the same otologist in our hospital from January 2015 to February 2017.Preoperative pure tone audiometry and high resolution temporal bone computed temography were performed and ossicular chain status was recorded intraoperatively on all patients.Assosication between air-bone gap(ABG)and ossicular chain status was analyzed and comparision was made between the diagnostic value of pure tone audiometry and high resolution temporal bone computed temography.Results:1.In CSOM,the air-bone gap of ossicular destruction and fixation was significantly higher than that of intact ossicular chains(P<0.05),while no major difference was noted between ossicular destruction and fixation.2.The average air-bone gap of ossicular distruction of CSOM was significantly higher than that of CHOLE(P<0.05).3.In CSOM,ABG at 0.5k,1k,2k,4k Hz and the average were predictive of ossicualr destruction.The diagnostic value of 0.5k Hz(OR=1.134,cut-off value=42.5 d B,AUC=0.866),1k Hz(OR=1.180,cut-off value=42.5 d B,AUC=0.910)and average ABG(OR=1.119,cut-off value=36.9 d B,AUC=0.881)was higher than 2k Hz(OR=1.103,cut-off value=22.5 d B,AUC=0.759)and 4k Hz(OR=1.053,cut-off value=42.5 d B,AUC=0.668).ABG at 0.5k,1k,2k,4k Hz and the average were also predictive of ossicualr fixation.The diagnostic value of 0.5k Hz(OR=1.125,cut-off value=32.5 d B,AUC=0.866),1k Hz(OR=1.131,cut-off value=32.5 d B,AUC=0.854)and average ABG(OR=1.213,cut-off value=29.4 d B,AUC=0.859)was higher than 2k Hz(OR=1.062,cut-off value=27.5 d B,AUC=0.658)and 4k Hz(OR=1.058,cut-off value=27.5 d B,AUC=0.674).4.In diagnosis of ossicular destruction of CSOM,the sensibility of pure tone audiometry is 70.6%,the specificity 93.5% and the accuracy 88.6%.The sensibility of high resolution temporal bone computed temography is 64.7%,the specificity100% and the accuracy 92.4%.No significant difference was noticed between the accuracy of two diagnostic methods.Conclusion:1.In CSOM,the influence of ossicular fixation is similar to that of ossicular destruction.2.Compared to middle ear cholesteatoma,ossicular destruction exerts larger influence on CSOM,resulting in more severe conductive hearing loss.3.Pure tone audiometry is of diagnostic value on ossicular status in CSOM,well complementing high resolution temporal bone computed temography.