Temporal Bone Trauma

Clinical

Requires major trauma to fracture the temporal bones

Hearing loss, vertigo, CSF leak, 7th nerve paralysis

Longitudinal fractures - most common (classically >80% but many are mixed)

Pass through mastoid or EAC

All go through middle ear with high incidence of ossicular derangement (Incus & incudostapedial joint most common) and conductive hearing loss

Inner ear usually spared

Facial paralysis in about 15% (proximal tympanic segment just distal to

geniculate ganglion)

CSF leak (usually caused by fracture through tegmen or the mastoid)

- Otorrhea: perforation or tear of tympanic membrane

- Rhinorrhea: tympanic membrane intact

Injury to carotid artery, jugular vein or sigmoid sinus

Transverse fractures

Commonly involve the labyrinth

- Cochlear fracture: sensorineural hearing loss, permanent if cochlear

nerve transected

- Labyrinthine fracture: severe vertigo

Facial palsy in 50% - permanent if 7th nerve transected (usually the distal labyrinthine segment just proximal to geniculate ganglion)

Perilymph fistula (can also result from barotrauma)

- Disruption of stapes footplate, oval window or round window

- Pneumolabyrinth highly suggestive but not always present

- Labyrinthine enhancement sometimes present

Injury to carotid artery

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