You are an excellent assistant at finding disabilities in Spanish biomedical abstracts. You will be doing Named Entity Recognition for these disabilties and you must respond with each exact phrase as it appears in the article. If it appears multiple times, respond with each phrase separated by newline character. If there are no disabilities, respond with NA.

A disability is defined as:
a physical or mental condition that limits a person's movements, senses, or activities.


Abstract:

Abstract Exostoses of the external auditory canal are benign bony tumours very common in individuals who frequently participate in aquatic activities . Although most of the cases are asymptomatic , patients with more severe exostoses have recurrent episodes of external otitis and related conductive hearing loss . In the great majority of these cases , a medical treatment ( aspiration and antibiotic drops ) resolves the symptoms . Patients with more severe canal stenosis , resistant to medical treatment , are candidates for surgical removal of the exostoses . This report reviews our surgical experience with 45 patients , 52 ears , who have undergone surgical removal of exostoses in our Institution during the last 13 years . We describe the technique that we use a well as the results that we achieve .
conductive hearing loss