Skull base fracture: Description
The skull base fracture (skull base fracture) is one of the skull fractures, just like the calvarial fracture (fracture of the skull roof) and the facial skull fracture. It is generally regarded as a dangerous injury, but usually not because of the fracture itself, but because the brain is often injured at the same time.
Types of skull base fracture
The most important types of skull base fracture are
- Longitudinal fracture of the petrous bone (frontobasal fracture)
- Transverse fracture of the petrous bone (laterobasal fracture)
In a transverse temporal bone fracture, the fracture gap begins on the posterior surface of the temporal bone pyramid, crosses the roof of the internal auditory canal and also extends towards the facial nerve canal and/or labyrinth (seat of the inner ear).
Skull base fracture: symptoms
The symptoms of a skull base fracture depend on whether it is a longitudinal or transverse fracture of the temporal bone. As numerous nerves and vessels pass through the base of the skull and can be injured by the fracture, different types of symptoms occur.
Symptoms of a longitudinal fracture of the petrous bone
The paranasal sinuses are also injured in a temporal bone fracture. Steps can also form in the external auditory canal. In some patients, the eardrum ruptures and the ossicular chain is interrupted so that sound conduction is impaired (conductive hearing loss).
In 15 to 25 percent of all cases of temporal bone fracture, the facial nerve is paralyzed (facial nerve palsy). Tearing off the olfactory nerves disrupts the sense of smell. Nasal fluid or blood can drain from the nose, ear or mouth.
Symptoms of a transverse temporal bone fracture
Basal skull fracture: causes and risk factors
A basilar skull fracture is caused by a strong impact on the skull, for example in the context of traffic accidents or fights. More than half of those affected have had a traffic accident, usually a head-on collision.
In around 17 percent of all patients with a fracture of the skull roof, the fracture gap extends into the base of the skull.
A skull fracture generally occurs together with a traumatic brain injury (TBI). An isolated skull base fracture is found in around four percent of all patients with severe traumatic brain injury. Due to the swelling in the facial area and because other consequences of the traumatic brain injury are usually in the foreground, the skull base fracture is often not noticed.
Patients with a basilar skull fracture often have multiple injuries (polytrauma) and are initially admitted to intensive care. In order to diagnose a basilar skull fracture, the doctor will first ask the patient – as far as their condition allows – about the circumstances of the accident and their medical history (anamnesis). Some of the doctor’s questions could be
- How did the accident happen?
- Are you in pain?
- Have you noticed any fluid leaking from your ears, mouth or nose?
- Do you have problems speaking, hearing or seeing?
Physical examinations
Ears
The doctor examines the patient’s external auditory canal to see if a step or ear secretion has formed. If the eardrum is still intact, blood usually accumulates in the middle ear (hematotympanum). If possible, the hearing function is then tested. A middle ear hearing loss can be differentiated from an inner ear hearing loss using a tuning fork.
Balance can be assessed with the so-called Frenzel glasses. If the organ of balance located in the inner ear fails, this leads to eye tremors (nystagmus).
Cranial nerves and large blood vessels
Leakage of secretions
If the affected person loses cerebrospinal fluid or blood from the nose, ear or mouth, this can also be an indication of a skull base fracture. As cerebrospinal fluid leaking from the nose looks very similar to nasal secretions, a laboratory examination is necessary. Special test strips are used to determine the sugar concentration (glucose concentration): The sugar concentration is higher in the cerebrospinal fluid than in the nasal secretions.
Diagnostic equipment
If the affected person has lost their hearing or has facial paralysis, a magnetic resonance imaging (MRI) scan will be performed. This can be used to rule out a hematoma in the brain and visualize facial nerves.
Basilar skull fracture: treatment
Patients with a skull base fracture must be monitored for the first 24 hours with bed rest and their head elevated. In addition, treatment depends on the extent of the skull base fracture.
Skull base fracture: conservative treatment
The injured ear canal is cleaned and covered with a sterile dressing. If the skull base fracture has led to a hearing loss in the inner ear, a so-called rheological treatment is initiated, as in the case of sudden hearing loss: Certain active substances are used in an attempt to improve blood circulation in the inner ear. Any dizziness that occurs can be alleviated with special medication (antivertiginosa).
If cerebrospinal fluid leaks from the nose, ear or mouth as a result of the skull base fracture, antibiotics must first be administered as a preventative measure to avoid an ascending infection. If the defect is located in the middle cranial fossa and the cerebrospinal fluid drains via the ear, this gap usually closes spontaneously and rarely needs to be treated surgically.
Skull base fracture: surgery
Surgery is always necessary for fractures in the area of the anterior cranial fossa (especially the lamina cribrosa) when neural fluid drains via the nose. This is because the gap does not close spontaneously and an infection can develop even years later. During the operation, the meninges (dura) are first closed so that they are impermeable to cerebrospinal fluid. The bone is then reconstructed.
Bleeding caused by ruptured cerebral vessels must also be surgically stopped. The surgeon removes the haematoma located in the so-called epidural space. This prevents the pressure in the brain from rising and causing brain damage.
Basilar skull fracture: course of the disease and prognosis
Basilar skull fracture: complications
Possible complications of a skull base fracture are
- Inflammation of the brain (meningitis)
- Accumulation of pus (empyema)
- Brain abscess
- Injuries to the carotid artery (carotid artery)
- Carotid sinus cavernosus fistula (vascular short circuit through which blood drains from the carotid artery into the venous plexus in the skull)
- Permanent cranial nerve lesions
Such complications can worsen the prognosis of a basilar skull fracture.
