The average age of patients was 35 years, ranging from 15 to 58 ; a male predominance was noted.
The main mechanism of injury is represented by road accidents.
The clinical symptomatology is dominated by conductive hearing loss in 27 patients and 20 patients presented with facial paralysis.
Associated intracranial injuries have been noted in 25 patients, corresponding to 50 % of cases, of varying severity.
It was subarachnoid hemorrhage in 11 cases, subdural hemorrhage in 5 cases, epidural hematoma in 4 cases and brain contusions in 5 cases.
Fractures were bilateral in 15 cases corresponding to 30 %.
Temporal bone fractures were longitudinal in 26 cases (44)%, transverse in 14 cases (36%), and mixed in 10 cases (20%).
Oblique fracture lines are the most common and lesions of the facial nerve canal were objectified in 20 patients.
The involvement of the outer ear is not reported in our series.
The lesions of the ossicular chain are present in 11 cases related to incudo-malleal dislocations (5 cases) incudo-stapedial dislocation (1 case), anvil fractures (3 cases), and handle of malleus (2 cases).
Labyrinthine lesions are present in 8 cases with pneumo labyrinth in 2 cases.
Computed tomography (CT) plays a fundamental role in the evaluation of patients with temporal bone trauma.
The most common mechanism of injury is motor vehicle crashes followed by falls and assaults.
Fractures of the temporal bone are common in patients with severe head trauma associated to skull base fractures.
Patients with temporal bone trauma also frequently have critical intracranial associated lesions such as subarachnoid, subdural, and epidural hemorrhage and brain contusions.
The clinical signs and symptoms of temporal bone fracture include hemorrhagic otorrhea, hearing loss, facial nerve paralysis, vertigo and nystagmus.
Trauma-related conductive hearing loss can be due tympanic membrane laceration, hematotympanum or ossicular injury.
Dedicated temporal bone multidetector CT should be performed every time there is a high degree of suspicion for temporal bone fractures and no fractures are identified at routine head multidetector CT.
Sometimes the fracture line is not seen on multidetector CT but some findings are suggestive of temporal bone fracture. These findings include opacification of mastoid air cells, the external ear canal or the middle ear; air-fluid level in the sphenoid sinus; pneumocephalus adjacent to the temporal bone and air in the glenoid fossa of the temporomandibular joint.
It important to describe the vital structures involved : ossicles, otic capsule, facial nerve, tegmen tympani, external auditory canal, internal auditory canal, carotid canal.
Classification of Temporal Bone Fractures:
Classifying temporal bone fractures helps physicians understand and predict associated complications and guide treatment.
The traditional classification system classified temporal bone fractures into two main categories, transverse or longitudinal, according to the orientation of the fracture line to the long axis of the petrous portion of the temporal bone.
Longitudinal fracture type:
The longitudinal fracture type is more common (80%–90% of temporal bone fractures) and results from temporo-parietal impact with the line of force extending lateral to medial.
The fracture line is parallel to the longitudinal axis of the petrous portion of the temporal bone (Fig 2).
Involvement of the otic capsule is rare.
Longitudinal fractures typically traverse the middle ear cavity, with frequent disruption of the ossicles.
The most common complications of longitudinal fractures are ossicular and tympanic membrane injury and hemotympanum with conductive hearing loss.
Transverse Fractures:
The transverse fracture type is less common (10%–20%) and results from fronto-occipital trauma with the line of force extending anterior to posterior.
The fracture line is perpendicular to the longitudinal axis of the petrous portion of the temporal bone with variable involvement of the otic capsule (Fig 5 ).
Facial nerve injury is more common in patients with a transverse fracture
Sensorineural hearing loss is also more common with this type of fracture and may be secondary to injury to the labyrinthine structures or stapes footplate injury, which results in perilymphatic fistula.
But some temporal bone fractures may not be strictly classified as longitudinal or transverse.
These type of fracture can be defined as mixed or oblique fracture
Mixed Fractures:
Mixed fractures include both longitudinal and transverse elements, with frequent involvement of the otic capsule.
There is a newer system that classifies fractures depending on whether the otic capsule is spared (otic capsule–sparing fracture) or violated (otic capsule-violating fracture)
The otic capsule–sparing fracture: is much more common (94%–97%), results from a temporoparietal blow and has an increased incidence of conductive hearing loss due to ossicular injury.
They are more commonly associated with intracranial injuries.
The otic capsule–violating fracture (3%–6%) results from an occipital blow and are more commonly associated with complications such facial nerve injury, sensorineural hearing loss, otorrhea and cerebrospinal fluid fistula.
On CT images, the otic capsule–violating fracture line can involve the cochlea, vestibule, semicircular canals and facial nerve.
The otic capsule–sparing or otic capsule–violating classification system seems to be the most valuable to help predict clinical outcomes and to tailor the treatment of patients with temporal bone fractures.