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Neuroradiology Case of
the Week
Case 172
Jerry Lee, MD, Guruprasad Srinath, MD, Sven Ekholm, MD, PhD,
and Per-Lennart Westesson, MD, PhD, DDS
Clinical
Presentation: Patient is
16-year-old male status post-assault.
Radiological Findings: The noncontrast CT scan of the head demonstrates a longitudinal fracture of the petrous portion of the right temporal bone with the fracture line passing though the middle ear and extending medially and anteriorly along the carotid canal and into the sphenoid bone (Figs. 1 & 2). Air fluid levels are visualized within the sphenoid sinuses (Figs. 1 & 2). Fluid is visualized within the right middle ear (Figs. 1 & 2). There is suspected dislocation between the malleus and incus (Fig. 2). Comminuted fracture of the right temporal bone and fracture of the planum sphenoidale of the sphenoid bone (Fig 3).
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| Figure 1: Longitudinal fracture of the right temporal bone (black arrows) and sphenoid bone (white arrow). |
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| Figure 2: Suspected dislocation of the malleus and incus with hematotympanum. |
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| Figure 3: Comminuted temporal bone fracture (black arrow) and fracture involving the planum sphenoidale (white arrow). |
Diagnosis: Longitudinal fracture of the temporal bone with extension into the sphenoid bone.
Discussion: Temporal bone fractures are usually the result of blunt head trauma and accounts for about 20% of all skull fractures. Common symptoms include vertigo, dizziness, sensorineural hearing loss, conductive hearing loss, and facial palsy. Intracranial complications include cerebral hemorrhage, parenchyma contusions, meningitis with or without CSF otorrhea, and occasionally carotid artery or jugular vein injury.
Temporal bone fractures are described according to their orientation to the long axis of the petrous bone: Longitudinal (70-90%), Transverse (10-30%) or Mixed.
The longitudinal fracture is that with courses parallel to the long axis to the petrous pyramid and often results from a blow to the temporoparietal region. Typically, the labyrinth is usually spared. The tympanic membrane is usually involved. Tympanic membrane rupture and hematotympanum most often is a sequel. Facial paralysis (10-20%) can occur secondary to damage to the facial nerve from intraneuronal hematoma, impingement by fracture fragments, or complete transaction. The ossicles are commonly involved resulting in conductive hearing loss. There is increased risk for developing cholesteatoma secondary to invasion of squamous epithelial debris into the middle ear along the fracture line.
The transverse fracture is that which courses perpendicular to the long axis of the petrous pyramid and often results from a blow from the frontal or occipital region. The fracture line commonly begins in the vicinity of the jugular foramen or foramen magnum and extends to the middle cranial fossa. The labyrinth is often involved leading to vertigo and sensorineural hearing loss. The tympanic membrane is usually spared. The ossicles are often spared (no conductive hearing loss). Facial paralysis (40-50%) is more common in this fracture.
References:
- Swartz JD, Harnsberger HR. Imaging of the Temporal Bone, 3rd Ed., New York, Thieme, 1998, pp. 318-344
- Swartz JD, Curtin HD. “Temporal Bone: Trauma.” IN: Head and Neck Imaging, 4th Ed., Som PM, Curtin, HD. St. Louis, Mosby, 2003, pp. 1230-1244.
- Carmody, RF. “The Temporal Bone.” IN: Neuroimaging: Clinical and Physical Principles. Aimmerman RA, Gibby WA, et al. New York, Springer, pp. 1171-1173
- Harnsberger HR, Wiggins RH, et al. Diagnostic Imaging: Head and Neck. Salt Lake City, Amirsys, pp. I2:196-199
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