Balloon Dilation of the Eustachian Tube

Inclusion Criteria: * ≥18 years old (of both sexes) * Diagnosed with persistent obstructive eustachian tube dysfunction (OETD) for at least 3 months prior to enrolment uni- and/or bilateral Diagnosis (both required): i. Persistent OETD symptoms assessed by Eustachian Tube Dysfunction Questionnaire (ETDQ-7) with overall score of ≥3 (moderate to severe symptoms) for 3 months or more prior to enrollment. ii. Refractory to medical therapy (minimum of 4 weeks of daily intranasal steroid spray or one completed course of an oral steroid within 3 months before study enrollment). Exclusion Criteria: * Patulous eustachian tube * Prior eustachian tube intervention * Presence of myringotomy ventilation tube or a tympanic membrane perforation * Active chronic or acute otitis media * Chronic otitis media with cholesteatoma * Fluctuating sensorineural hearing loss or Meniere's disease * Chronic rhinosinusitis, allergies, or reflux disease not controlled with medication * History of head or neck surgery within 3 months * Prior radiation to the head and neck * Active temporomandibular joint disorders * Cleft palate or Craniofacial syndrome * Cystic fibrosis or Ciliary dysmotility syndrome or Systemic immunodeficiencies * Active acute upper respiratory infection * Nasal endoscopy with evidence of anatomic conditions that would prevent transnasal access to the Eustachian tube * CT temporal bone scan with evidence of carotid artery dehiscence, superior semicircular canal dehiscence, or ext…