Skull Base Fractures
Skull base fractures are traumatic fractures of the bones that form the floor of the skull. Because cranial nerves and blood vessels pass through these bones, such fractures can lead to complications including cerebrospinal fluid leakage (fistula), cranial nerve injury and vascular injury. The diagnosis is made with thin-slice CT, and most cases are managed conservatively.
Last updated: 2026-06-07
Definition
Skull base fractures are traumatic fractures of the bones that form the floor of the skull (the basal parts of the frontal, ethmoid, sphenoid, temporal and occipital bones). Anatomically they are grouped into anterior, middle and posterior skull base fractures. Because many cranial nerves and major vessels pass through this region, these fractures derive their importance less from the bone injury itself than from the accompanying complications.
Causes and Complications
The most common causes are high-speed road traffic accidents, falls from height and direct impacts. The skull base bones are thin and contain air spaces (sinuses, mastoid); trauma can damage these structures and the nerves and vessels running through them. The main complications are leakage of cerebrospinal fluid through the nose (rhinorrhea) or ear (otorrhea) from a dural tear and the associated risk of meningitis, cranial nerve injuries (smell, vision, eye movements, facial movements, hearing and balance), injuries to vessels such as the carotid or vertebral artery, and accumulation of air within the skull (pneumocephalus).
Symptoms
In anterior skull base fractures there may be bilateral bruising around the eyes (raccoon eyes), clear fluid discharge from the nose and loss of smell. In middle skull base fractures there may be a collection of blood behind the eardrum, bruising behind the ear (Battle sign), fluid discharge from the ear, facial palsy, hearing loss and dizziness. In posterior skull base fractures, lower cranial nerve findings such as difficulty swallowing and speaking and deviation of the tongue may occur, and more serious presentations are possible because of proximity to the brainstem. In vascular injuries, pulsatile protrusion of the eye or signs of stroke may appear.
Diagnosis
Thin-slice high-resolution brain CT is the gold standard; the bone window shows the fracture line, intracranial air, blood-fluid levels in the sinuses and fractures of the foramina (openings). Coronal and sagittal reconstructions and examination of the temporal bone provide detailed assessment. Where vascular injury is suspected, CT angiography and, if needed, digital subtraction angiography (DSA) are performed. To confirm cerebrospinal fluid leakage, a beta-2 transferrin test on the discharge is used. Cranial nerve function is assessed with clinical examination, hearing tests and, where needed, nerve conduction studies.
Treatment Options
In most stable skull base fractures, conservative treatment is the first step. Elevation of the head of the bed, avoidance of maneuvers that raise intracranial pressure (forceful nose-blowing, straining) in patients with cerebrospinal fluid leakage, and avoidance of nasal/ear packing are recommended. A significant proportion of cerebrospinal fluid leaks close on their own; for fistulas that persist for a long time or are accompanied by recurrent meningitis, surgical repair is performed via an endoscopic endonasal or open approach. Management of cranial nerve injuries varies with the type and degree of injury; in facial palsy, corticosteroids or surgical decompression may be considered depending on the situation. Vascular injuries may require endovascular treatment.
Course and Recovery
While a period of observation may be sufficient in uncomplicated skull base fractures, a cerebrospinal fluid fistula, cranial nerve injury or vascular injury determines the course. Once a cerebrospinal fluid leak is closed, the risk of meningitis falls markedly. Recovery of cranial nerve function varies with the degree of injury and the time of onset. Posterior skull base fractures are monitored more closely because of their proximity to the brainstem and vital centers. Outcomes vary from patient to patient and no result can be guaranteed.
References
- Greenberg MS. Greenberg's Handbook of Neurosurgery. 10th ed. Thieme; 2023:1064-1071.
- Carney N, Totten AM, O'Reilly C, et al. Guidelines for the Management of Severe Traumatic Brain Injury. 4th ed. Neurosurgery. 2017;80(1):6-15.
- Oh JW, Kim SH, Whang K. Clinical and demographic characteristics of skull base fractures. J Korean Neurosurg Soc. 2018;61(6):729-735.
This article is for general information and does not replace a medical examination. Diagnosis and treatment decisions are individual.