The Contralateral Ear in Unilateral CSOM, Endoscopic, Audiologic and Radiologic Evaluation

<i>Background</i>: The aim of this study was to assess the contralateral ears in patients with unilateral CSOM with and without cholesteatoma, clinically (using otoendoscpy), auiologically and radiologically, then analyzing and comparing results between the 2 types of CSOM in a trial to examine the continuum theory for the development of the disease process in CSOM. Patients and methods: A prospective, observational study including 85 patients with unilateral COM (with or without cholesteatoma), the study was conducted at the Otorhinolaryngology Department, Damietta Faculty of Medicine, Al-Azhar University, Egypt between August 2020 and December 2021. <i>Results</i>: In the present study (30.59%) of cases were having a unilateral squamous disease and (69.41 %) were mucosal CSOM, (70.6%) of patients having a diseased contralateral ear, of which (76.9%) having squamous disease and (67.8%) having mucosal CSOM. Pars tensa retraction was the most common abnormality (60%) seen in cases with squamous OM while thin TM was the most common abnormality (50%) of cases with mucosal CSOM. Pars tensa retraction was more severe in CLE of patients with squamous disease, (41.7%) were grade 4, while in mucosal type (50%) were grade 1. HRCT of mastoid reveled abnormalities in (24.7%) of all CLEs, more prevalent (62%) in the CLEs of cases with squamous disease than cases with mucosal COM. Audiologic examination of the CLE revealed (47%) having conductive hearing loss CHL of average 32.1 dB {36.5 dB average hearing loss in (70%) of cases with squamous type and 27.7 dB average hearing loss in (30%) of cases with mucosal CSOM}. Tympanometric evaluation of the CLEs revealed (50.6%) having abnormal curve {(73%) of cases with squamous type where type C curve was found in (84.2%) and type B curve in (15.8%)}, and in (40.7%) of cases with mucosal CSOM. where type C curve was found in (83.33%) and type B curve in (16.7%). <i>Conclusions</i>: The present study has confirmed the presence of high incidence of abnormalities in the CLEs of unilateral squamous and mucosal COM which is more in squamous type, it emphasizes the importance of considering both ears as a pair. Disease in one ear especially in squamous type needs a close follow up of other ear, as in most cases there a hidden pathology which needs attention for complete cure. Otoendoscopy can be helpful in diagnosing and documenting masked pathologies.