Fractures of the rock – a bony structure located in the lower part of the temporal bone – are common in victims of head trauma following an accident. Their seriousness is due to the complications that can appear, sometimes years later: deafness, facial paralysis, meningitis, etc. 

Definition

Rock fractures are bone lesions that appear following severe head trauma.

The rock is a piece of bone in the shape of a four-sided pyramid, which forms the inner part of the temporal bone, on the side of the skull. It is carved out by the bony labyrinth – the bony cavities of the inner ear: vestibule, circular canals and cochlea, or cochlea – and is crossed by the facial nerve.

Lesions can be extra-labyrinthine or labyrinthine, when they extend to the inner ear. In particular, they can affect the organs of hearing or the facial nerve.

Causes

The injuries are caused by a direct or indirect impact following an accident or a fall.

There are two main types of rock fracture depending on the nature of the impact:

• longitudinal fractures, parallel to the axis of the rock, are caused by a side impact.
• transverse fractures, perpendicular to its axis, are caused by impact to the front or back of the skull.

Complications depend on the extent of the fracture, depending on the point of impact and the severity of the shock.

Diagnostic

Neurological risks are usually given priority after a head trauma and a fracture of the rock may go unnoticed, especially in polytrauma patients in a coma.

An early diagnosis is however necessary to detect lesions and assess their consequences. The initial imaging workup is based on a specific high-resolution CT scan (computed tomography or CT), focused on the temporal bone.

If a lesion of the labyrinth or the facial nerve is suspected, MRI can be used to complete the imaging workup.

The people concerned

The fracture of the rock is a frequent pathology, which represents 7 to 25% of all intracranial lesions in the event of multiple trauma or simple cranial trauma. The people concerned are often rather young.

Longitudinal fractures are very predominant.

Risk factors

Some activities expose you to a greater risk. Accidents on the public highway thus come largely to the head of the causes of cranial trauma and fracture of the rock, while falls are favored by certain sports practices (skiing, etc.).

Acute alcoholism increases the risk of accidents and falls. Assault can also cause such fractures.

A benign rock fracture may well not cause any symptoms. In more severe cases, certain clinical signs will alert specialists. 

Otarragie (sign of Laugier)

Otarrhagia, which is blood flow from the ear, is a common symptom of a rock fracture with tearing of the eardrum.

The eardrum may also be unopened and appear bulging with a hematoma, due to bleeding in the eardrum.

Deafness

Deafness can be total or partial (hearing loss) and reveal different types of damage to the inner or middle ear.

When it results from a defect in the air transmission of sound due to the presence of blood in the eardrum, it disappears in less than three weeks. It is more durable when the eardrum is torn, and permanent in some cases, especially when the ossicles of the middle ear are damaged, which affects the bone transmission of sound.

We speak of sensorineural hearing loss when the cochlea is affected. Indeed, this organ filled with liquid, in the shape of a snail, plays a fundamental role in transmitting the sound signal to the auditory nerve.

Facial paralysis

Relatively frequent, it is most often due to an indirect lesion of the facial nerve by compression or elongation. Facial paralysis can be immediate or progressive onset.

Other symptoms

• Otorrhea (discharge of fluid from the ear) may raise concerns about the existence of an extensive breach in the meninges (osteomeningeal breach), through which cerebrospinal fluid flows. The risk of contracting meningitis is then increased.
• Persistent dizziness suggests damage to the labyrinth.
• The lesions can also cause persistent tinnitus, nausea, vomiting, balance disturbances

In itself, a rock fracture does not require specific treatment.

Local care and symptomatic treatments

These treatments should be considered on a case-by-case basis to relieve the patient and avoid complications: drainage, administration of corticosteroids to help the edema to subside or antibiotics to prevent meningitis, antivertiginous and / or antiemetic treatment in the event of nausea. and vomiting …

surgery

Surgery is sometimes possible to repair the eardrum (when the perforation does not close spontaneously), the ossicles, the inner ear, the facial nerve or the osteomeningeal breaches.

Management of sequelae

Deafness must be taken care of by a specialist. In particular, he will assess whether improvements can be made by a cochlear implant or hearing aids.

Physical therapy can be helpful in relieving dizziness.

In the event of balance disorders, vestibular rehabilitation is based on strategies that will help the patient learn to compensate for his deficits. For example, we will train him to keep his balance on mobile platforms.