The association between auditory nerve neurovascular conflict and sudden unilateral sensorineural hearing loss.

Hypothesis: There may be an association between a neurovascular conflict (NVC) of the auditory nerve and unilateral sudden sensorineural hearing loss (SSNHL).

Background: Compression of cranial nerves by vascular structures can lead to significant symptomatology that may require surgical decompression. Notable examples are trigeminal neuralgia and hemifacial spasm. Magnetic resonance imaging (MRI) is part of the workup for SSNHL, and it may depict an NVC of the auditory nerve. Here we look into the association between this NVC and unilateral SSNHL.

Methods: A retrospective analysis was performed on all consecutive patients with unilateral SSNHL who underwent an MRI scan in our medical center. The data collected included age, gender, side and severity of hearing loss, and accompanying complaints. Each MRI scan was reviewed by a neuroradiologist who was unaware of hearing loss laterality. The presence, side, extent, and location of a potential NVC involving the auditory nerve were determined, and a correlation between radiological findings and auditory parameters was sought.

Results: Fifty-four patients (male-to-female ratio 26:28, age range 25-80 years) were enrolled into the study. Fourteen of them (25.9%) had normal MRI findings. Twenty-six patients had a unilateral NVC, and the pathology was ipsilateral to the side of hearing loss in only 12 of them (46.2%). Fourteen (25.9%) patients had MRI findings of bilateral NVCs. There was no significant correlation between the side of the SSNHL and any radiological findings ( P  = .314).

Conclusion: The data presented herein support the conclusion that there is no association between CN8 NVC and unilateral SSNHL.

Level of Evidence: 2b.