It is commonly seen in the elderly and in diabetic patients. Malignant otitis externa is a result of infection of the EAC with Pseudomonas aeruginosa. Mortality has currently decreased to 20% from 30-40% due to good improved antibiotics. Malignant otitis externa is a misnomer as it is not a malignant condition it is termed “malignant” because of the aggressive clinical behavior and high mortality associated with it. 3D reconstructed images should demonstrate the volume of the middle ear cavity and also the distance from the middle ear structures to the atretic EAC and reveal any other anomalies of the external ear. Additional anomalies need to be looked for as well, such as the presence of severe incudomallear dysplasia, which when present has to be resected, as well as dysplastic stapes, which may need to be replaced by a prosthesis. In addition, we also need to look for structures that may cause problems during surgery such as reduced volume of the middle ear cavity and poor pneumatization of the temporal bone.
Preoperatively, the radiologist should look for contraindications for surgery such as atretic oval and or round window and unfavorable course of the facial nerve. HRCT of the temporal bone is indicated for preoperative planning. The outcome of surgeries performed in the presence of middle and inner ear dysplasia are not encouraging.
Isolated EAC atresias are amendable to surgery.
Atresia of the EAC can occur in isolation or it may be associated with middle ear and inner ear dysplasia.
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