Spontaneous Stapediovestibular Dislocation with Congenital Duplication of the Tympanic Segment of the Facial Nerve: A Case Report.

External stapediovestibular dislocations are rare and often traumatic. Congenital facial nerve anomalies, as in this case, make reconstruction of the ossicular chain even more challenging.A 37-year-old woman patient presented progressive bilateral hearing loss and aural fullness for 1 month in May 2024. She had suffered a fall from a height of approximately 4 stories in 2017. The audiometry showed bilateral conductive hearing loss with an air-bone gap greater than 50 dB. A temporal bone computed tomography scan showed suspected stapes detachment and facial nerve anomalies in both ears. Right exploratory tympanotomy revealed external stapediovestibular dislocation with duplication of facial nerve in the tympanic segment. A type V tympanoplasty with piston wire insertion was performed. Audiometry after right ear surgery showed closure of the air-bone gap by 42 dB, without vertigo or facial nerve injury.Surgery aims to prevent facial nerve injury while successful restoring hearing loss. The cause of stapediovestibular dislocation is discussed, along with methods for reconstruction of the ossicular chain.