Yanagihara et al proposed a classification for temporal bone fractures that correlates with the clinical complications. The authors are from Ehime University in Ehime, Japan.
|
Anatomic Extent of Fracture Line |
Type |
|
across the mastoid process but not extending to the external auditory canal |
1 |
|
across the mastoid process to the external auditory canal |
2 |
|
across the mastoid cortex and external auditory canal with damage to geniculate ganglion and/or middle ear |
3 |
|
across the tegmen of the middle ear and the antrum, with no direct injury to the inner ear or internal auditory canal |
4A |
|
across the tegmen of the middle ear and the antrum, with direct injury to the inner ear and/or internal auditory canal |
4B |
where:
• A Type 4B fracture corresponds to a transverse fracture.
• Combinations may occur with Type 2 & 3, 2 & 4, 3 & 4, and 2 & 3 & 4.
|
Type |
Portion of Facial Nerve Involved |
Other Complications |
|
1 |
mastoid segment |
transient hemotympanum from hemorrhage into middle ear |
|
2 |
mastoid and pyramidal segments |
transient hemotympanum from hemorrhage into middle ear |
|
3 |
pyramidal and/or horizontal segment; geniculate ganglion |
laceration of ear drum, ossicular chain damage with conduction hearing loss, perilymphatic fistula |
|
4A |
pyramidal, horizontal and/or labyrinthine segments; geniculate ganglion |
dry eye, CSF otorrhea, ossicular chain damage with conduction hearing loss |
|
4B |
pyramidal, horizontal and/or labyrinthine segments; geniculate ganglion |
dry eye, CSF otorrhea, sensorineural hearing loss, spontaneous nystagmus, fracture of internal auditory canal |
Injury to the facial nerve may involve:
(1) complete transection
(2) external compression from a spicule of bone
(3) external compression from head of malleus
(4) distortion of facial canal
(5) internal compression from edema and swelling, which may be followed by fibrosis
Specialty: Surgery, orthopedic, Emergency Medicine, Critical Care, Surgery, general, Otolaryngology
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