Answers:
Blows to the lateral side of the skull often result in --- fx of t-bone whereas blunt trauma to the occipital skull result in --- fx of t-bone.
A) Longitudinal, Transverse
B) Longitudinal, Vertical
C) Transverse, Vertical
D) Transverse, Longitudinal
E) Vertical, Longitudinal
MC Questions:
Diagnose this fracture.
A) Mastoid fracture
B) Transverse Temporal bone fracture
C) Longitudinal Temporal Bone Fracture
D) Occipital Bone fracture
A) Longitudinal, Transverse
B) Longitudinal, Vertical
C) Transverse, Vertical
D) Transverse, Longitudinal
E) Vertical, Longitudinal
What is the most common type of temporal bone fracture?
Longitudinal fractures comprise 80% of tbone fractures. Transverse fracturse comprise 20%. However, transverse fractures are more likely to involve the otic capsule.
Diagnose this fracture.
B) Transverse Temporal bone fracture
C) Longitudinal Temporal Bone Fracture
D) Occipital Bone fracture
Free Response Question:
After a temporal bone fracture, what degree of delayed facial nerve degeneration is required in order to benefit from surgical decompression.
Quick Facts:
Complications of Temporal Bone Fractures
-Conductive Hearing Loss:
-most commonly from hemotympanum but also TM perf or ossicular
discontinuity.
-Most common OD is incudostapedial joint dislocation.
-Ossicular fixation can occur several months after trauma if new bone formation
at the line of the fx fuses to the ossicular chain.
-Sensorineural Hearing Loss and Vertigo
-In transverse temporal bone fxs w/ otic capsule involvement.
-Pneumolabyrinth is often noted on CT.
-Audiogram shows complete SNHL in affected ear.
-Clinical exam reveals nystagmus
-Can get SNHL w/o otic capsule involvement if labyrinthine concussion, traumatic
noise exposure or blast occurs. THought to be due to testing of the cochlear
membrane and/or trauma to hair cell epithelium due to rapid acceleration and
deceleration forces in the inner ear.-Facial
-Nerve Injury:
-Occurs in 20% of longitudinal and 50% of transverse fxs.
-Important to delineate whether facial nerve injury was immediate or delayed.
-Delayed present w/ normal function that worsens slowly over hours-days.
-Likely from edema within facial nerve without disruption of neural integrity.
-Immediate facial nerve palsy likely due to nerve transection
-Cerebrospinal Fluid Leak
-2% incidence of CSF leak in all skull fxs, 20% in Tbone fxs.
-Usually occurs within first 48 hrs.
-Clear fluid from ear/nose. Worse with straining, standing up, bending over.
-Can collect and send of B2 transferrin testing.
Posttraumatic Encephalocele
-Can result if large defect in floor of the middle cranial fossa occurs.
-Dura and temporal lob can herniate down into middle ear.
After a temporal bone fracture, what degree of delayed facial nerve degeneration is required in order to benefit from surgical decompression.
Quick Facts:
Complications of Temporal Bone Fractures
-Conductive Hearing Loss:
-most commonly from hemotympanum but also TM perf or ossicular
discontinuity.
-Most common OD is incudostapedial joint dislocation.
-Ossicular fixation can occur several months after trauma if new bone formation
at the line of the fx fuses to the ossicular chain.
-Sensorineural Hearing Loss and Vertigo
-In transverse temporal bone fxs w/ otic capsule involvement.
-Pneumolabyrinth is often noted on CT.
-Audiogram shows complete SNHL in affected ear.
-Clinical exam reveals nystagmus
-Can get SNHL w/o otic capsule involvement if labyrinthine concussion, traumatic
noise exposure or blast occurs. THought to be due to testing of the cochlear
membrane and/or trauma to hair cell epithelium due to rapid acceleration and
deceleration forces in the inner ear.-Facial
-Nerve Injury:
-Occurs in 20% of longitudinal and 50% of transverse fxs.
-Important to delineate whether facial nerve injury was immediate or delayed.
-Delayed present w/ normal function that worsens slowly over hours-days.
-Likely from edema within facial nerve without disruption of neural integrity.
-Immediate facial nerve palsy likely due to nerve transection
-Cerebrospinal Fluid Leak
-2% incidence of CSF leak in all skull fxs, 20% in Tbone fxs.
-Usually occurs within first 48 hrs.
-Clear fluid from ear/nose. Worse with straining, standing up, bending over.
-Can collect and send of B2 transferrin testing.
Posttraumatic Encephalocele
-Can result if large defect in floor of the middle cranial fossa occurs.
-Dura and temporal lob can herniate down into middle ear.
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