The term skull fracture refers to any disruption of the integrity of the osseous structure surrounding the brain.
Symptoms may vary widely depending on the nature of the SF and possibly compromised tissue.
As has been stated above, the majority of SF corresponds to linear SF without considerable damage to underlying structures. These patients are most frequently aware of their surroundings and do not experience neurological deficits. They usually present external lesions that result from the causative trauma, e.g. abrasions, other skin lesions and swelling.
Depressed SF tend to be more severe than linear SF and more than half of the patients that suffers from depressed SF loses conscience for less than an hour. Symptoms rarely observed with linear SF are more prevalent in these cases. Seizures may be triggered by brain lesions.
In basilar SF, loss of consciousness is likely. They are typically associated with cerebrospinal fluid otorrhea or rhinorrhea and bruising of the temporal or zygomatic bone, respectively. Hearing impairment may be associated with basilar SF and may result from transient middle ear hemorrhages and inflammation or from nerve damage, in which case deafness would be permanent. The patient's sense of balance may be disturbed and they may show ataxia. Due to close proximity to cranial nerves, cranial nerve palsies are frequently observed in basilar SF. Trigeminal nerve (V), abducens nerve (VI) and facial nerve (VII) are most frequently affected and the respective patients will show nystagmus and limited facial sensation and motor function.
SF affecting the occipital bone may not only depict injuries to glossopharyngeal nerve (IX), vagal nerve (X), accessory nerve (XI) and hypoglossal nerve (XII), such injuries may also comprise severe cervical spine and spinal cord injuries . Their autonomous nervous system may be severely compromised. Also, hemiplegia or quadriplegia may be observed in these patients.
Medical history, when available or clinical presentation may lead to the tentative diagnosis of SF. Such may be the case if otorrhea or rhinorrhea test positive for cerebrospinal fluid. However, conscious patients with good overall condition usually do not suspect that they might have sustained a SF. Thus, the further workup for SF is mainly based on imaging techniques, even though laboratory analyses of blood samples should be made to better assess the overall condition of the patient.
Computed tomography is the method of choice to visualize the bony skull in detail and has been proven to be more sensitive than traditional radiographic imaging   . To this end, sensitivity and specificity of computed tomography for SF have been calculated to be 85% and 100%, respectively .
Magnetic resonance tomography may be more suitable to detect soft tissue damage and therefore supplements computed tomography scans in order to detect possible lesions to underlying structures, particularly the brain.
Treatment for SF consists in bed rest, head elevation, drug therapy and possibly surgery.
Bed rest and head elevation should suffice to enable the patient's body to recover from linear SF. While adults who are not experiencing any symptoms may rest at home, children should be admitted overnight for observation in any case of SF . Symptomatic treatment may be applied to alleviate pain. Antibiotic treatment is not necessary.
Even a significant share of depressed and basilar fractures may be treated without surgery. With regards to the latter, patients should be advised to avoid blowing their nose in order to avoid spreading the air from any potentially lesioned paranasal sinus. If the patient is at risk to experience seizures, anticonvulsant medication may be administered.
If the underlying meninges suffered minor damage, it is usually self-limiting and repair processes should not last longer than a week. Cerebrospinal fluid leaks should be closed by then. Surgery becomes necessary if this is not the case.
Of course, surgery is also indicated if there is any risk that osseous fragments damage the brain or blood vessels or if such damage has already occurred and needs to be treated, e.g. in cases of contamination, hematoma or pneumocephalus. Not only bone fragments but also necrotic tissue and foreign bodies should be removed from the site of injury. If possible, bone fragments should then be fixed in their physiological position. Perioperative measures have to be taken to avoid tissue infection and abscess formation. Broad-spectrum antibiotics may be administered for this purpose. Compound fractures require measures to prevent tetanus. Surgical interventions to treat SF are considered safe procedures and complications are usually expected from the causative trauma rather than from surgery .
SF may have an unfavorable or even poor prognosis, if the brain, its cranial nerves or major blood vessels are damaged during the causative trauma.
However, the majority of SF corresponds to linear fractures sustained by children. They are usually not associated with any injury to vital structures or intracranial hematoma. In most cases, surgery is not necessary. Permanent neurologic damage is not to be expected and the prognosis is good .
Etiology differs with age groups and while blunt traumas may cause SF at any age, fetuses and infants are more prone to particular types of SF. Ping-pong SF, for instance, may be diagnosed in newborns whose head sustained traumas during birth. Usually, they result from the impact of the baby's head against the sacral promontory of their mother . Only in rare cases, babies sustain head injuries when manipulated with forceps.
Otherwise, infants may suffer from SF due to falls or abuse. These causes may also apply to older children, but SFs affecting the latter most often result from bicycle accidents. Children may be involved in motor vehicle accidents, but this is more often seen in adults.
Of note, substantial force needs to be applied to fracture the skull of a healthy individual. However, pathological alterations of bone formation, disease and degeneration may leave certain patients more susceptible to fractures.
There are no reliable data regarding the overall incidence of SF. However, estimates regarding the incidence of head injury and emergency evaluation of the former range above one million annual cases in the United States alone . About one in three assaulted patients suffers SF .
Studies revealed that the most frequently fractured bone is the parietal bone, followed by the temporal, occipital and frontal bone . With regards to SF types, linear fractures are most commonly observed . Also depressed and basilar SFs are not rare events, contrary to diastatic ones. The low overall incidence of diastatic SF results from the fact that children are significantly more prone for sutural diastasis.
SF results from mechanical forces that exceed the maximal capacity of resistance of the bony skull. As has been mentioned above, considerable force needs to be applied to fracture the skull of a healthy individual and certain parts of the skull may fracture more easily than others. In the majority of cases, such forces originate from blunt traumas. Here, one trauma may involve different kinds of forces. For instance, a gunshot injury may consist in direct tissue damage as inflicted by the bullet but may also result from shock waves developing in close proximity to the high-speed bullet. This example may also serve to explain that the traumatic force may act in different directions. While the bullet itself exerts its major force alongside the bullet path, shock waves distribute perpendicular to that path. In contrast, slower bullets may not be accompanied by these shock waves, but may inflict even greater damage upon impact because they may trigger wedge-shaped fractures rather than perforations of the skull.
Depending on force and direction, SFs are not necessarily accompanied by severe damage to internal structures and vice versa.
The vast majority of SF results from blunt trauma. While children may sustain head injuries when falling down or having an accident with their bicycles, motor vehicle accidents account for the majority of SF in adults. Thus, children should not be left alone, particularly not where they may fall and hurt their heads. With regards to riding a bicycle, a motorcycle or driving a car, the corresponding safety measures should be taken into account, e.g. helmet and safety belt.
There are several anatomic structures that protect the brain: This vital organ is surrounded by a thin film of cerebrospinal fluid, by the soft meninges pia and arachnoid mater, by the hard meninx dura mater and by the bony skull. Also, the protective role of scalp fascia and muscles need not be underestimated .
While all these structures may eventually be affected by head injuries, it is the bony skull itself that resists major forces. The local, maximal resistance of the skull needs to be exceeded for a patient to sustain a skull fracture (SF). In this context, it has to be mentioned that distinct skull sections are able to withstand different forces. For instance, the external angular processes and glabella of the frontal bone and the external occipital protuberance of the occipital bone are particularly thick and resistant spots. Due to differences in bone formation, particularly regarding development of the cancellous bone layer of the flat cranial bones, muscle-covered skull sections and those in close proximity to the nose remain rather thin and are more susceptible to SF. Also, parietal, sphenoid and temporal bones are rather prone to fracture as well as the foramen magnum of the occipital bone.
The vast majority of SF results from blunt trauma. Here, the forces provoking SF may or may not be directed at the skull and may yield different types of SF. In this context, linear, depressed, basilar and diastatic fractures of the skull are usually distinguished. They differ in incidence among age groups and in severity. Of note, the term compound SF refers to cases where tissues usually protected inside the skull become exposed to the environment, e.g. due to lesions of scalp and skull.
SFs are usually not the most severe consequences of a blunt trauma, sufficiently strong to break the bony skull. In contrast, damage to brain, blood vessels and meninges may be lethal even though the accompanying SF seems less severe.
The term skull fracture (SF) refers to any disruption of the integrity of the bones that protect brain and face. There are many different types of SF, particularly linear, depressed, basilar and diastatic ones. They may affect any section of the bony skull, but there are certain parts that are more prone to fractures than others. For instance, the central spot between the brows is particularly thick and hard to break, while this is not the case for these bones that form face and temples.
SFs most commonly result from blunt traumas that, in turn, may occur during falls, bicycle or motor vehicle accidents and due to violence. The former are more frequently observed in children, the latter in adults. To avoid SF, always watch children, have them wear a helmet when riding a bike and take the recommended safety measures while traveling in motor vehicles.
Considerable force is necessary to break the skull of a healthy individual.
SFs are diagnosed with imaging techniques. The method of choice to visualize the bony skull is computed tomography. Frequently, computed tomography scans will be integrated with magnetic resonance imaging in order to assess possible damage to adjacent tissues.
SF therapy largely depends on the nature of the fracture and on accompanying tissue damage. Indeed, the SF itself does usually cause little complications. However, head injuries are potentially fatal if underlying soft tissue, particularly brain, nerves or blood vessels, are damaged.
Most SFs can be treated conservatively, i.e. with wound cleansing, bed rest, head elevation and analgesics. If the neurologist considers the patient to be in risk of seizures, anticonvulsants will also be administered. Closed SFs do usually not require antibiotics.
Surgery becomes necessary if the above mentioned soft tissues are damaged or are at risk of damage.