Traumatic Facial and Vestibulocochlear Nerve Injury in The Internal Acoustic Canal in The Absence of A Temporal Bone Fracture

Abstract

We present a rare case of traumatic facial and vestibulocochlear nerve injury in the internal acoustic canal in the absence of a temporal bone fracture. A 2.5-year-old female presented with sudden-onset left-sided facial paralysis and ipsilateral total hearing loss after being hit by a falling television. High-resolution computed tomography revealed an occipital fracture line that spared the temporal bone and otic capsule. Diagnostic auditory brainstem response testing showed that wave V at 90-db normal hearing level was absent in the left ear. Needle electromyography revealed severe axonal injury. Facial paralysis regressed to House-Brackmann grade IV 9 months after the trauma, and no surgical intervention was scheduled. Traumatic facial and vestibulocochlear nerve injury can occur in the absence of a temporal bone fracture. Thus, careful evaluation of the internal acoustic canal is mandatory if concurrent 7th and 8th cranial nerve paralyses exist with no visible fracture line.

Cell Transplantation to Restore Lost Auditory Nerve Function is a Realistic Clinical Opportunity

“…The auditory nerve is particularly vulnerable to external force in the regions of the fundus of the internal auditory canal and the transitional zone (TZ) [36][37][38][39][40][41] . When the medial displacement of the brainstem is greater than that of the cochlea in the temporal bone, the resultant force on the auditory nerve may avulse the auditory neurons from the fundus of the internal auditory canal [36][37][38][39][40][41] . The TZ is the interface between the CNS and PNS 43 , and it can be highlighted by immunostaining for glial fibrillary acidic protein (GFAP), which is expressed by astrocytes only in the CNS 2 and it lies within the internal auditory canal 44 (Fig.…”

“…In patients with a closed head injury even without temporal bone fractures, damage to auditory neurons is observed primarily and/or secondarily following HC damage 36 – 42 . Clinically, cases in which the auditory nerve is damaged without damage to HCs are most suitable for cell transplantation because the HCs can provide trophic support, as mentioned above ( Fig.…”

Chameleons, red herrings, and false localizing signs in neurocritical care

“…36 Notably, this damage leading to hearing loss can be caused by temporal bone fracture, trauma even in the absence of fracture, transient demyelination, and infarction due to stroke. [37][38][39] As a FLS, hearing loss, in addition to the other otologic symptoms of pulsatile tinnitus and aural fullness, has been reported as a complication of IIH. 3,40 The hearing loss is low-frequency and may also present with vertigo.…”

Traumatic facial nerve injury: A case of facial nerve avulsion at the cerebellopontine angle

“…It usually occurs after blunt injury to the cranium with temporal bone fractures [ 2 , 3 ]. A common injury site is the facial nerve canal between the entry at the lateral terminus of the internal auditory canal and the exit at the stylomastoid foramen [ 3 , 4 ]. Computed tomography (CT) examinations are often performed to investigate the site of the bone fracture, bony fragments, and the presence of a hematoma.…”

“…There are some reports of MRI of post-traumatic facial nerve palsy with abnormal enhancement [ 5 , 6 ]. However, less is known about cases with facial nerve avulsion [ 3 , 4 ]. We report a case of facial nerve injury, in which facial nerve avulsion was observed 21 years after the trauma.…”