Skull fractures

Skull bone fractures most typically occur due to blunt force trauma from contact sports, motor vehicle collisions, or falls. Skull fractures are classified according to the anatomic location of the fracture as basilar skull fractures, cranial vault fractures, mandibular fractures, and midfacial fractures. Fractures of the skull base are classified according to the affected region (anterior, middle, posterior cranial fossae). Cranial vault fractures may involve the frontal, parietal, temporal, sphenoid, and occipital bones. Midfacial bone fractures and basilar skull fractures can be simple (i.e., involving a single bone, e.g., nasal bone fractures, temporal bone fractures, zygomatic arch fractures) or complex (i.e., involving more than one bone, e.g., Le Fort fractures of the midfacial bones or zygomaticomaxillary complex fractures). All skull fractures can be subclassified further based on the number of fracture lines (simple or comminuted fractures), the degree of displacement (nondisplaced or depressed fractures), and the involvement of soft tissue (open or closed fractures). Clinical features vary depending on which bones are involved but usually include facial pain, bruising, palpable step-off(s), and mobile bone fragments. Initial management of skull fractures focuses on identifying and addressing life-threatening injuries. Watchful waiting may be sufficient for simple fractures, but neurosurgery may become necessary in unstable fractures and such complicated by CSF leaks or cranial nerve lesions. Complications of skull fractures include CSF leaks (with an increased risk for meningitis), cranial nerve disorders (due to compression or transection), epidural hematomas, and facial disfiguration.

For details regarding orbital floor fractures, please see the article “Traumatic eye injuries.”

Classification by fracture type

• Linear skull fracture (most common type of skull fracture)
  • A single fracture that extends through the entire width of one or more skull bones
  • Typically occurs as a result of low-energy blunt trauma to a large surface of the skull (e.g., fall).
  • Characteristics
    • Number of fracture lines: simple or comminuted fracture possible
    • Soft tissue involvement: closed fracture or compound fracture possible
    • Location: Most commonly involves the temporal, parietal, frontal, or occipital bones.
• Depressed skull fracture
  • A skull fracture in which the skull depresses inward toward the brain parenchyma
  • Typically occurs secondary to a high-energy blunt force injury to a small area of the skull (e.g., impact with a baseball bat).
  • Characteristics
    • Number of fracture lines: typically a comminuted fracture
    • Soft tissue involvement: compound fracture more common than closed fracture
    • The parietal and frontoparietal regions are the most common sites.
• Open skull fracture: a fracture that is associated with a dural tear that results in communication between the CNS and with the outer environment, either through the skin, sinuses, or ears
• Diastatic skull fracture
  • A fracture along the skull suture lines
  • Most commonly seen in newborns and infants

Classification by location

• Basilar skull fractures
  • Fractures involving the anterior, middle, and posterior cranial fossae
  • Temporal bone fractures (longitudinal or transverse fractures)
• Cranial vault fracture
  • A fracture of one or more of the cranial vault bones (frontal, parietal, temporal, sphenoid, and occipital bones).
  • Most commonly involves the frontal and parietal bones.
  • Depending on the mechanism of injury, cranial vault fractures can be linear or depressed.
• Midfacial fractures
  • Nasal bone fracture
  • Zygomatic bone fracture
  • Orbital floor fracture
  • Frontal sinus fracture
  • Complex facial fractures (e.g., Le Fort fractures, zygomaticomaxillary complex fracture)
• Mandibular fracture

Clinical features ^[1]

Clinical features depend on the type of skull fracture. Common signs and symptoms of skull fractures are listed below. See the individual sections below for details.

• Hematoma, local swelling, and laceration of the scalp
• Facial and/or nasal swelling, epistaxis, visible deformity
• A palpable gap along the surface of the bone; bone crepitus when the fracture fragments are moved.
• Liquorrhea: typically occurs immediately or within the first few days after the trauma
• Epidural hematoma
• Signs and symptoms of traumatic brain injury
  • Loss of consciousness, headache, amnesia, symptoms of increased ICP, and focal neurologic deficits
  • More common in depressed skull fractures and basilar skull fractures

Definition

• A skull fracture that involves the nasal bones, lacrimal bone, ethmoid, sphenoid, maxilla, zygomatic bone, and/or palatine bone.

Epidemiology

• ♂ > ♀
• Peak incidence: age 20–30 years ^[2]
• The majority of midfacial fractures involve the nasal bone and the zygomatic bone.

Etiology

• Sports-related injuries are the most common cause.
• Other causes of blunt trauma to the face include violent altercations (punches, elbowing) and falls. ^[3]
• See the column on “Type of fracture” in the table on Le Fort fractures below for details regarding the mechanism of injury.

Classification and clinical features

• Facial contusions, local swelling, and tenderness
• Facial asymmetry and midface instability of varying degree
• Palpable gap along the surface of the bone
• Isolated nasal bone fractures and zygomatic fractures are discussed separately.

Diagnostics

• Physical exam: Assess for midfacial instability, concomitant orbital, nasal, and dental injuries, and cranial nerve palsies.
• Noncontrast cranial CT (modality of choice): Evaluate the type and number of midfacial fracture(s), continuity of orbital boundaries, and degree of soft-tissue involvement with thin slices and 3D reconstruction.
• Ophthalmic exam: indicated in Le Fort II and Le Fort III fractures to detect ocular injuries (e.g., vitreous hemorrhage, retinal detachment, globe rupture)
• CSF tests: if a dural tear is suspected (see “Diagnostics” in “Basilar skull fractures” for details)

Treatment

• Immediate stabilization of any life-threatening injuries
• Conservative management for nondisplaced linear skull fractures without vascular or neurologic injuries
• Operative management ^[3]
  • Indications: unstable midfacial fractures, major facial deformity, and fractures with neurologic, vascular, or ocular compromise
  • Procedure
    • Open reduction and internal fixation
    • Intraoperative adjustment of dental malocclusion
    • Restoration of facial structures and proportions

Epidemiology ^[5]

• Most common type of facial bone fracture
• Adults: 5% of all facial fractures ^[6]
• Infants: 16% of all facial fractures ^[6]

Etiology ^[6]

• Motor vehicle crashes
• Physical violence (e.g., punches, elbowing)
• Sports-related injuries (e.g., soccer, basketball)

Clinical features ^[7]

• Epistaxis
• Swelling and ecchymosis of the nasal bridge
• Crepitus upon palpation
• Nasal deformity

Diagnostics ^[7]

• Physical examination
  • External examination
  • Internal examination (after remission of the swelling)
  • Inspection of all facial bony structures
• Imaging: cranial CT (if other facial fractures and/or skull fractures are suspected)

Treatment ^[7]

• Conservative management: acute, uncomplicated nasal fractures
  • Head elevation
  • Pain medication
  • Cooling with ice
  • Nondisplaced, linear fractures: no further treatment
  • Displaced nasal fractures: closed reduction and external fixation with a nasal splint
• Operative management: severely displaced nasal fractures

Complications

Nasal septal hematoma ^[8]

• Definition: a collection of blood around the nasal septal bone or cartilage with intact nasal mucosa
• Etiology: nasal or facial trauma
• Clinical features
  • Unilateral or bilateral obstruction of the nasal lumen with blood-filled mucosa
  • Absence of overt bleeding (due to intact nasal mucosa)
• Diagnostics: rhinoscopy showing unilateral or bilateral balloon-like bloody protrusion
• Treatment: immediate surgical drainage

Nasal septal hematoma always requires treatment due to the high risk of infection.

Other

• Nasal septal perforation secondary to nasal septal hematoma
• Saddle nose deformity
• Deviated nasal septum
• Nasal ventilation problems and snoring

Definitions ^[9]

• Zygomatic arch fracture: isolated fracture of the zygomatic arch
• Zygomaticomaxillary complex fracture: complex lateral midfacial fracture involving the zygomatic arch, inferior and lateral orbital rim, and the anterior and posterior maxillary sinus walls

Epidemiology

• Second most common type of midfacial bone fracture ^[9]

Etiology

• Sports-related injuries (e.g., direct impact with sporting equipment or players)
• Physical altercations (e.g., punch or elbow impact with the malar eminence)

Clinical features

• Cheekbone contusion, local swelling, lacerations
• Asymmetry of the malar eminence, depression of the affected side
• Impaired mastication and/or trismus
• Anesthesia of the cheek and upper lip (due to infraorbital nerve injury)
• Orbit injury
  • Unilateral periorbital hematoma
  • Diplopia
  • Ophthalmoplegia
  • Enophthalmos

Diagnostics

• Physical exam: Evaluate zygomatic symmetry and stability, palpable gaps along the surface of the bone, bone crepitus.
• Cranial CT (modality of choice)
  • Evaluate the type and number of fracture lines, displacement of bone fragments and/or rotation, and the contour of the orbital boundaries.
  • Assess the orbital roof and orbital floor.
• Ophthalmic examination: Evaluate visual acuity and ocular movement to rule out extraocular muscle entrapment.

Treatment

• Conservative management
  • Indications: nondisplaced or minimally displaced stable fractures
  • Procedure
    • Analgesia
    • Physical measures (cooling, decongesting nose drops) and functional relief (e.g., soft food)
    • Closed reduction of minimally displaced, uncomplicated fragments
    • Observation
• Operative management
  • Indications: displaced or comminuted fractures, zygomatic arch instability, functional impairment (e.g., trismus, muscle entrapment, diplopia), facial deformity (e.g., orbital globe positioning, malar eminence asymmetry)
  • Procedure: open reduction and internal fixation (e.g., miniplates, screws) to restore function and malar symmetry

Definition

• A skull fracture that involves at least one of the bones that make up the skull base, namely the ethmoid, sphenoid, occipital, paired frontal, and paired temporal bones

Etiology

• Basilar skull fractures occur as a result of significant high-energy blunt trauma to the head
• Most commonly secondary to motor vehicle, motorcycle, or pedestrian collisions
• Other causes: violent altercations, falls, firearm injuries

Classification and clinical features

• Clinical features depend on the location of the fracture (see table below).
• Concomitant traumatic brain injury (50% of cases): loss of consciousness, headache, amnesia, symptoms of increased ICP, and focal neurologic deficits ^[10]
• Epidural hematoma (proximity to the middle meningeal artery)
• Cranial nerve palsies

Raccoon eyes, Battle sign, and CSF leakage are highly indicative of basilar skull fractures.

Neurological impairment, repeated vomiting, and seizures indicate potentially severe cerebral trauma or intracranial hemorrhage.

Diagnostics

• Approach
  • Identify and treat life-threatening injuries (primary survey, GCS).
  • See “Diagnostics in traumatic brain injury” for details.
  • Imaging should be performed once the patient has been stabilized.
  • Further diagnostics as needed e.g., ophthalmic exam, otoscopy
• Physical examination
  • Note the location and type of injury (scalp lacerations, contusions, deformities, facial asymmetry), wound contamination, signs of fracture, liquorrhea.
  • Neurological exam: Assess for cranial nerve injuries.
• Imaging
  • Noncontrast high-resolution cranial CT with bone window (modality of choice)
    • Evidence of skull fractures
      • A discontinuity in the bone structure (with or without displacement)
      • Pneumocephalus: air within the cranium; typically associated with an open skull fracture
      • Hyperdensity in neighboring structures (e.g., paranasal sinus, middle ear, mastoid air cells) indicate hemorrhage
  • Facial radiographs, if CT is unavailable (low sensitivity)
  • MRI: may be performed to assess soft tissue injury (higher sensitivity than CT)
  • Ultrasound can aid in the detection of ocular injuries (e.g., vitreous hemorrhage, retinal detachment, globe rupture).
• CSF tests: blood-tinged rhinorrhea and/or otorrhea may indicate dural tear and should be evaluated for the presence of CSF.
  • Detection of β2-transferrin (gold standard) ^[1]
    • β2-Transferrin is found exclusively in CSF and in the perilymph of the inner ear.
    • Evidence of β2-transferrin in electrophoresis is used as a specific marker of a CSF leak.
  • May show a halo sign: rapidly-expanding clear ring of fluid surrounding blood suggests the presence of CSF when drops of the leaking fluid are applied to gauze or tissue paper ^[12]

Treatment

• Initial management
  • Immediate stabilization of any life-threatening injuries
  • See also the treatment of “Traumatic brain injury.”
  • See treatment of “Intracranial hemorrhage.”
• Conservative management
  • Mainstay approach for most linear skull fractures without vascular or neurologic injuries
  • Involves closed reduction, closure of wounds, wound care, and pain medication
• Operative management ^[1][13]
  • Indications
    • Displaced or comminuted linear skull fractures
    • Open fractures with gross contamination/wound infection or penetrating injuries
    • Intracranial hematoma
    • Significant cranial nerve injury
    • Functional impairments (e.g., muscle entrapment, ocular compromise)
    • Persistent CSF leak (> 7 days)
  • Surgical repair typically involves open reduction and internal fixation preferably within 7–10 days of the injury
• Empiric antibiotic prophylaxis: generally not recommended ^[14][15]
  • May be indicated in:
    • Penetrating skull fracture
    • Open head injury with significant wound contamination
    • Consider in patients with a basilar skull fracture and persistent CSF leakage (> 7 days)
• Further treatment is based on concomitant injuries (e.g., auditory ossicle dislocation)

Nasogastric tubes and nasotracheal intubation are absolute contraindications in the setting of basilar skull fractures due to the risk of intracranial tube placement.

Complications

• Meningitis
• Pneumocephalus
• Panhypopituitarism

Definition

• Fracture of the temporal bone that typically involves the petrous part of the temporal bone.

Etiology

• Very high-energy blunt trauma to the temporal bone (often in association with polytrauma)
• Most commonly occurs in motor vehicle collisions or other traffic-related injuries (e.g., bicycle vs. pedestrian collisions).

Classification and clinical features

• Possibly, signs of traumatic brain injury
• Injury to the external auditory canal and tympanic membrane is common.
• Cranial nerve palsies (CN I, CN V, CN VI, CN VII, CN VIII)
• Epidural hematoma (proximity to the middle meningeal artery)
• Injury to the otic capsule significantly increases the risk of facial nerve palsies, CSF leak, and sensorineural hearing loss.

Diagnostics

• See “Diagnostics” in “Basilar skull fractures” above for details.
• Noncontrast cranial CT (modality of choice)
  • Fracture lines in the petrous part of the temporal bone
  • Hyperdensity in the mastoid air cells indicate hemorrhage
• Otoscopy: inspect tympanic membrane (see table above for findings)
• For CSF otorrhea: detection of β2-transferrin and halo sign

Treatment

• See “Treatment” in “Basilar skull fracture” above for details.
• Facial paralysis: systemic corticosteroids
• Surgery may be indicated for the following cases: ^[16]
  • Dural repair
  • Middle ear reconstruction
  • Facial nerve decompression or grafting

Complications

• Meningitis
• Posttraumatic benign paroxysmal positional vertigo
• Traumatic endolymphatic hydrops