Right temporal bone fracture with ossicular dislocation.

55-year-old male patient found in coma with blunt head trauma after falling from a second-floor height, presenting haemotympanum. In the follow up he presented persistent conductive hearing loss.

Head CT showed severe intracranial injuries. The presence of haemotympanum suggested temporal bone involvement and a right transverse temporal bone fracture was despicted, with an entry point in the anterior part of the horizontal squamous bone, extending to the middle ear with incudomalleal dislocation. The fracture line does not extend into the otic capsule. There is opacification of some mastoid cells and the middle ear.

Background: Temporal bone injury must be suspected in high-energy head trauma, specially when haemotympanum is present, with temporal fractures present in 14-20% of skull fractures. [1]

Clinical Perspective: Classifying temporal bone fractures helps physicians predict trauma-associated complications and guide management and treatment. [1,2] Also clinical information provided (characteristics of the hearing loss, signs of facial paralysis) can help the radiologist.

Imaging perspective:
The traditional classification system considers the relationship of the fracture line with the long axis of the petrous portion of the temporal bone. Longitudinal fractures (70-90%) usually associate ossicular injury, tympanic membrane rupture, and haemotympanum with conductive hearing loss. Less commonly, the facial nerve also may be injured. Tranverse fractures (10-30%) associate sensorineural hearing loss secondary to injury to the labyrinthine structures, transection of the cochlear nerve, or stapes footplate injury, which results in perilymphatic fistula. Facial paralysis is more common. [1]
The otic capsule sparing vs otic capsule-violating classification is more relevant to predict complications and guide management. In the otic sparing type ossicular injury and conductive hearing loss is more common; whereas neurosensorial hearing loss, balance dysfunction, facial nerve paralyses and cerebrospinal fluid leak is more common in otic-violating fractures. [1,2]
This case is a transverse type fracture, but extending to the middle ear with incudomalleal disjunction, as it is an otic capsule sparing type, inner ear structures where preserved.

Outcome: In the follow up patient presented persistent conductive hearing loss.

Take home messages: Look for temporal bone fractures in severe brain traumas, they can be identified in routine head multidetector CT. [1] Dedicated temporal bone multidetector CT should be considered when there is a high degree of suspicion for temporal bone fractures and no fractures are identified at head CT. [1,2]
The otic capsule sparing vs otic capsule-violating classification is more relevant to predict complications and guide management.