What Is a Skull Fracture?

Skull fractures are divided into skull cap and skull base fractures according to the fracture site; they are divided into linear fractures, depression fractures, comminuted fractures, cave fractures and penetrating fractures according to the fracture form; according to whether the fracture is connected with the outside world, it is divided into open and closed Fracture. Open fractures include fractures of the skull base with dural rupture and traumatic pneumonia or cerebrospinal fluid leakage.

Duan Wanru	(Resident)	Department of Neurosurgery, Xuanwu Hospital, Capital Medical University
Zhao Ruilin	(Deputy Chief Physician)	Department of Neurosurgery, Xuanwu Hospital, Capital Medical University

Skull fracture refers to a disease in which one or more of the bones of the head are partially or completely broken, mostly caused by blunt impact. Most of the changes in the skull structure do not require special treatment, but if it is accompanied by damage to the tissue structure in the skull near the stress point, such as rupture of blood vessels, brain or cranial nerve injury, meningeal tear, etc., it needs to be handled in time, otherwise it may cause intracranial Serious complications such as hematoma, impaired nerve function, intracranial infection, and cerebrospinal fluid leakage affect prognosis.

Western Medicine Name

Skull fracture

Affiliated Department

Surgery-Neurosurgery

Disease site

skull

Contagious

Non-contagious

Skull fracture classification

Skull fractures are divided into skull cap and skull base fractures according to the fracture site; they are divided into linear fractures, depression fractures, comminuted fractures, cave fractures and penetrating fractures according to the fracture form; according to whether the fracture is connected with the outside world, it is divided into open and closed Fracture. Open fractures include fractures of the skull base with dural rupture and traumatic pneumonia or cerebrospinal fluid leakage.

Causes and mechanisms of skull fractures

Skull fractures occur as a result of the reaction force generated by the violent action on the skull. If it is revealed that the reaction force moves in the direction of the violent action and no reaction force is formed, it will not cause a fracture. Since the tensile strength of the skull is always less than the compression strength, when violent action occurs, the part that always bears the tensile force ruptures first. If the area of the blow is small, the skull will mostly become the main part of the skull; if the area of focus is large, it can cause the overall deformation of the skull, which is often accompanied by extensive brain damage.

Skull fracture local skull deformation

After the skull was hit, the focused part was sunken first. If the violence is fast and the area of effect is small and does not exceed the elastic range of the skull, the skull will rebound immediately; if it exceeds the elastic range, the central area will focus on the cone and sink into the cranial cavity, causing the internal and external rupture of the bone. If the rupture stops on the inner plate, it is a simple inner plate fracture, and chronic headache may occur in the later stage; if the outer plate is also fractured, a local depression and a peripheral annular and linear fracture are formed. If the traumatic violent effect is not exhausted, the fractured piece can sink into the cranial cavity and form a crushed depression or cavity fracture.

Skull fracture

The skull can be simplified as a hemisphere model, the skull cap is hemispherical, and the skull base is the bottom. When under pressure, the entire skull can be deformed. When the direction of violence acts laterally, the fracture is often perpendicular to the sagittal line, folding to the temporal and skull base; violence is anterior and posterior, the fracture line is often parallel to the sagittal line, forward to the anterior cranial fossa, and backward to the occipital bone. Can cause sagittal suture fracture. In addition, when the violence acts vertically on the central axis of the body, it can be transmitted along the spine to the skull base. In the light, it causes a linear fracture of the skull base. In severe cases, it can cause a life-threatening cranial basement ring fracture and fall into the skull.

Skull fracture regularity

Traumatic factors such as the direction, velocity, and area of violence have a greater impact on skull fractures, which are summarized as follows: The force axis of violence and its main component force direction are mostly consistent with the extension of the fracture line, but the thickened skull arch is encountered When the beam structure is used, it is often folded towards the weak bone. When the area of violent action is small and fast, cave-shaped fractures often form, and bone fragments sink into the cranial cavity. If the impact area is large and the speed is fast, it will cause local comminuted depression and fracture; if the area of the action point is small and the speed is slow, it will often cause linear fractures through the force point; if the area of the action is large and the speed is slow, Can cause comminuted fractures or multiple linear fractures. Strikes perpendicular to the skull can easily cause local depression or comminuted fractures; oblique strikes often cause linear fractures and extend in the direction of the force axis; they often fold toward the base of the skull; occipital injuries often cause occipital fractures or extensions to the temporal Fractures of the middle and middle cranial fossa.

Skull fracture pathophysiology

Skull cap fractures, that is, fornix fractures, are most common in the parietal and frontal bones, followed by the occipital and temporal bones. There are three main forms of skull cap fractures, namely linear fractures, comminuted fractures and sunken fractures. The shape, location and direction of the fracture are closely related to the direction, speed and focus of violence. The fracture line of a linear fracture often passes through the superior sagittal sinus, transverse sinus, and meningeal sulcus, which can cause intracranial hemorrhage. Depressed fractures are usually caused by a blunt strike with a small contact surface or a collision of the skull with a protruding object. The skull near the point of focus is mostly trapped in the skull, and may have symptoms and signs of brain compression.

Skull base fractures are mainly linear, which can be limited to a certain cranial fossa. It can also cross through the cranial bases on both sides or through the anterior, middle and posterior fossa. Because the fracture line often involves the paranasal sinuses, rock bones, or mastoid air cells, the cranial cavity and sinus cavity communicate to form an invisible open fracture, so it can cause secondary intracranial infection.

A frontal forehead attack can easily cause a fracture of the anterior cranial fossa, and the fracture line often passes through the saddle to reach the occipital bone. For a frontal lateral attack, the fracture line can cross the midline through the sieve plate or toward the sphenoid saddle to the contralateral anterior cranial fossa or The middle cranial fossa; the frontal part was attacked, the fracture line extended to the anterior cranial fossa or the middle cranial fossa; the interparietal area was hit, which could cause the fracture line from the middle cranial fossa to the contralateral anterior cranial fossa; the posterior parietal area was stressed and fractured The line points to the bottom of the middle cranial fossa and crosses the saddle or saddle inward to the opposite side; the occipital is stressed, and the fracture line can extend through the occipital bone to the rock bone, or it can be folded to the rock tip to the middle cranial cavity through the foramen magnum. Or through the saddle to the anterior cranial fossa.

Clinical manifestations of skull fracture

(Linear fractures) Skull fracture linear fractures (Linear fractures)

Simple linear fractures do not need to be treated by themselves, but their importance lies in brain injury or intracranial hemorrhage caused by fractures, especially epidural hematomas, which often cause bleeding because the fracture line crosses the middle meningeal artery, especially children. . When the fracture line passes through the temporal muscle or occipital muscle on the temporal bone or occipital bone attachment area, the temporal muscle or occipital muscle may swell and bulge. This sign also indicates that a fracture has occurred there.

(Depressed fractures) Depressed fractures of skull fractures

Depression fractures are more common in the forehead and top. Generally, simple depression fractures, complete scalp without brain injury, mostly closed injuries, but comminuted depression fractures are often accompanied by dura mater and brain tissue damage, and even cause intracranial hemorrhage.

Skull fracture closed depression fracture

There are many children, especially infants with good skull elasticity, and blunt wounds can cause skull depression, but the scalp is intact, similar to table tennis depression, and no obvious fracture line is visible. Most patients have no neurological dysfunction, but when the depression is larger and deeper, symptoms and signs of brain compression may be present.

Skull fracture open depression

It is usually caused by a strong blow or falling from a high place on an object with prominent corrugated angles. Often, the scalp, skull, dura, and brain are affected at the same time, resulting in open brain injury. There are two types of open depression fractures: cave fractures and comminuted depression fractures.

Fractures of cavern-shaped depressions are mostly caused by small objects hitting the contact surface, and most of them are weapons that directly penetrate the scalp and skull into the cranial cavity. The shape of the fracture is often the same as the shape of the wound, which is an important basis for forensic identification of the weapon. Bone fragments are often trapped deep in the brain tissue, causing severe local brain damage, bleeding, and foreign body retention. However, due to the small overall deformation of the skull, there are generally no extensive skull fractures and diffuse brain injuries. Therefore, the clinical manifestations of cave fractures are often based on local nerve defects.

The smashed sag fracture is accompanied by the depression of the force bones, which often causes injuries to large objects in the contact area. Not only the local skull deformity is obvious, causing people to collapse. At the same time, the overall skull deformation is also large, causing most of the focus points. Centered radial fracture. The dura mater is often punctured by bone fragments, and the brain injuries are more serious. In addition to local impact injuries, there are often hedgehog contusions or intracranial hematomas.

Skull fracture

Most of the skull base fractures are linear fractures, most of which are skull fractures that extend to the skull base, and some are depression fractures, which can also be caused by indirect violence. According to the location of its occurrence: anterior cranial fossa, middle cranial fossa, and posterior cranial fossa fracture.

Fracture of the anterior cranial fossa:

Involving the orbital apex and ethmoid bone, there may be nosebleeds, extensive periorbital blood stasis spots (panda eyes), and extensive subconjunctival hemorrhage. Among them, "Panda Eye" is of great significance for diagnosis. If the meninges and periosteum are ruptured, combined with cerebrospinal fluid rhinorrhea and / or pneumonia, the cranial cavity can communicate with the outside world. Therefore, infection may occur and it should be considered as an open injury. Cerebrospinal fluid nasal leakage is mostly bloody in the early stage, and must be distinguished from epistaxis. In addition, anterior fossa fractures often have unilateral or bilateral olfactory disorders. Intraorbital hemorrhage can cause eyeballs to protrude. If the optic nerve is affected or the optic nerve tube is fractured, there may still be different degrees of visual impairment.

Fracture of the middle cranial fossa:

Fractures in the middle fossa often involve rock bones, and if sphenoid bones are involved, there may be nosebleeds or combined cerebrospinal fluid and nasal slippage. Cerebrospinal fluid flows from the nostril through the sphenoid sinus. If the temporal bone is involved, the structure of the inner ear or middle ear cavity can be damaged. Patients often have phrenic and iliac cranial nerve injuries, which are manifested as hearing impairment and peripheral facial paralysis. When the meninges, periosteum, and tympanic membranes are ruptured, cerebrospinal fluid ear leak, cerebrospinal fluid It flows from the external ear canal through the middle ear; if the tympanic membrane is intact, the cerebrospinal fluid flows through the eustachian tube to the nasopharynx, which can be mistaken for a nasal leak. If the medial part of the sphenoid bone and the temporal bone is involved, the pituitary gland or the nerves of the II, III, IV, V, VI may be damaged. If the fracture hurts the carotid cavernous sinus segment, pulsatile exophthalmos and intracranial murmur may occur due to the formation of arteriovenous fistula; rupture of the hole or internal carotid artery can cause fatal nosebleeds or ear bleeding.

fracture of posterior cranial fossa:

When the posterolateral part of the temporal bone is involved, subcutaneous ecchymosis (Battle sign) appears in the mastoid part 1 to 2 days after injury. If the base of the occipital bone is involved, swelling of the lower occipital region and subcutaneous bruising may occur within a few hours after injury; fractures near the foramen magnum or near the posterior edge of the apex of the pelvis may be combined with posterior cranial nerve (the first iliac cranial nerve) injury.

Diagnosis and differential diagnosis of skull fracture

Skull fracture diagnosis

1. Diagnosis of skull fracture

For closed skull fractures, if there is no obvious depression, it is only a linear fracture. It is difficult to confirm the diagnosis based on clinical signs alone, and it is often necessary to perform plain X-ray examination. Even for open fractures, if you want to know the specific situation of the fracture, especially the location and number of fracture fragments into the human skull, it still depends on X-ray examination.

2. Diagnosis of skull base fracture

Most of the skull base fractures are caused by the skull cap fracture line extending to the skull base, and a few can be caused by cranial crush injuries. The diagnosis of skull base fractures is mainly based on clinical manifestations. X-ray plain films are not easy to show skull base fractures and are not helpful for diagnosis. CT scan can clearly show the location of the fracture by adjusting the window width and distance. It is not only helpful for the diagnosis of orbital and optic nerve tube fractures, but also for the presence or absence of brain injury, so it has important value. When in doubt about cerebrospinal fluid leakage, the effluent can be collected for quantitative glucose determination. When there is a cerebrospinal fluid leak, it is actually an open brain injury.

Differential diagnosis of skull fracture

Scalp hematoma

Subcutaneous hematomas are generally small in size, sometimes due to swelling and bulging of the tissue around the hematoma, but the center is depressed, which is easy to be mistaken for a depressed skull fracture, which needs to be identified with a skull x-ray.

Orbital injury

Orbital injury can cause periorbital ecchymosis, and it can also appear as "panda eyes", and should be distinguished from skull fractures. A history of ocular trauma, intraorbital, subconjunctival hemorrhage, and invaginations or dyskinesias all indicate periorbital fractures, such as maxillary and sacral fractures. Can be identified by CT.

3. Otitis media and rhinitis

Otitis media, especially chronic otitis media, may have the appearance of purulent ears, rhinitis often manifests with clear water, and these should be distinguished from cerebrospinal fluid ear leaks and nasal leaks caused by skull fractures. The main points of identification include: the history of trauma, whether fever is present, and the characteristics of the outflow of fluid.

Emergency measures for skull fracture

Skull fractures are not life-threatening themselves, and urgent treatment is a fatal complication. Fractures of the middle cranial fossa can sometimes cause severely large nasal epistaxis, which can result in death from shock or suffocation and requires urgent management. The endotracheal tube should be intubated immediately to clear the blood in the airway to ensure breathing. Then the nasal cavity is filled, sometimes the posterior nasal cavity is blocked by the pharynx. The blood loss is quickly replenished. Save lives. In the acute phase of posterior cranial fossa fracture, if there is respiratory dysfunction or cervical spinal cord compression, tracheotomy and cranial traction should be performed as early as possible, assisted or artificial breathing if necessary, and even decompression of posterior cranial fossa and cervical spine. If there is shock, it should be corrected first.

Firearm open craniocerebral injury is a special type of craniocerebral injury that often occurs on the battlefield. The first aid procedure is:

Keep the airway unobstructed: The simple method is to push and pull the lower jaw forward, lie on the side, suck out respiratory secretions and vomit, and intubate for excessive ventilation.

Rescue shock: Emphasizing that early adequate blood transfusion and control of airways are the two main principles of gunshot wound treatment in war and peacetime. Firearm penetrating wounds can be used for emergency transfusion of low-titer "O" type whole blood, but it is best to lose the same type of blood.

First aid for severe brain compression: In a short period of time, the injured person may experience unilateral dilated pupils or rapid changes in both pupils, breathing slows down, and when it is estimated that they cannot be transferred to the surgical hospital, the penetrating injury entrance should be enlarged quickly, and the wound may be shallow. Layer of hematoma can often gush out and rescue some of the wounded before considering transfer.

Wound dressing: On-site rescue is only for simple wound dressing to reduce bleeding. When there is a brain bulge, use a dressing around it to protect the brain tissue from contamination and increase damage. Emphasis on direct delivery to specialists, but those who have shown shock or signs of central failure should be given first aid at the site and should not be transferred. Initiate high-dose antibiotic therapy as soon as possible and use TAT. ^[1]

Skull fracture treatment

Skull fractures account for about 15-20% of craniocerebral injury, and can occur in any part of the skull, with the parietal bone the most, the frontal bone second, the temporal bone and the occipital bone second. Fractured or fractured fractures can damage both the meninges and the brain as well as cerebrovascular and cranial nerves. Generally, the fracture line does not cross the cranial suture. If the violence is too large, it can also affect the adjacent bone. Due to the fracture location and shape, the treatment and prognosis are also different. The secondary injury caused by a fracture is much more serious than the fracture itself. Be alert to intracranial hematomas, and watch the condition within 48 hours. If the condition worsens, a skull CT scan should be performed early to find the intracranial hematoma in time. If a fractured piece is inserted into the brain or compresses the functional area, causing seizures, early surgery should be performed.

Treatment of skull fractures

The principle of treatment of skull fracture is surgical reduction. Indications for surgery:

(1) The depth of the fractured piece in the cranial cavity is more than 1cm;

(2) Large-scale fractures are trapped in the cranial cavity, and the intracranial pressure is increased due to bony compression or concurrent bleeding;

(3) Those who have fractured the brain tissue and caused signs of the nervous system or epilepsy. Severe fractures located in the sinus of the large vein, such as those that cause signs of the nervous system or increased intracranial pressure, should also be repaired or removed. If the defect is too large, it should be left for repair at a later date. Adequate blood transfusion equipment must be prepared before surgery to prevent major bleeding during fracture rehabilitation. Close observation should be performed after surgery to prevent bleeding.

Treatment of skull fractures

Most skull base fractures do not require special treatment, but focus on the combined brain injury and other concurrent injuries. Ear and nose bleeding and cerebrospinal fluid leakage should not be blocked or flushed to avoid causing intracranial infection. Most cerebrospinal fluid leaks stop on their own in about two weeks. If it lasts for more than four weeks or if the intracranial gas accumulation persists, surgery should be performed in time to repair the cerebrospinal fluid fistula and close the fistula. For optic nerve or facial nerve damage caused by crushing of bone fragments, the bone fragments should be removed by surgery as soon as possible. Fractures of the skull base with cerebrospinal fluid leakage are open injuries and require antibiotic treatment. ^[2]

Prognosis of skull fracture

The prognosis of skull fracture mainly depends on the location of the fracture, the presence or absence of complications, and the timely treatment. If the skull fracture did not cause other complications such as vascular rupture, meningeal injury and craniocerebral injury, most of them healed well after conservative treatment. If complications are present and not addressed in a timely manner, a poor prognosis may result.

Skull fracture prevention

The skull is an organ that contains and protects brain tissue. The bone is thick. Generally, small violence will not cause skull fracture, and larger violence or action point will only cause fracture of the skull. In terms of prevention, employees in the mining and construction industries should wear safety helmets and strictly abide by the code of practice. When encountering violence, they should protect their heads, especially the temporal area. Because the temporal bone is thin and there is a middle meningeal artery running, fractures here can easily lead to the rupture of the middle meningeal artery, causing acute epidural hematoma, heavy bleeding, and the risk of cerebral hernia.

Growing skull fracture (GSF) is a special type of skull fracture. It often occurs after acute dissociative skull fracture in infants and children, and the incidence rate is 0.05-1%. The main clinical manifestations are cystic mass in the head, local skull defect, neurological dysfunction and epilepsy. Therefore, early prevention is very important.

For patients with acute craniocerebral trauma, it should be judged at an early stage whether it will progress to a growth skull fracture, and if there is a risk of progressing to a growth skull fracture, surgery should be performed. It has been reported in the literature that in patients with isolated skull fractures in infants and young children, if the width of the fracture line is greater than 3mm, while bleeding hemorrhagic cerebrospinal fluid or broken brain tissue is drawn in the local scalp, or if the MRI clearly indicates that the hernia is brain tissue, it is hard The meninges have been ruptured, which is the pathological basis for growing skull fractures in the future. In principle, after the vital signs are stable, surgery should be performed on the 3rd to 5th days after the injury to prevent the occurrence of growth skull fractures.

Skull fracture care

Care for patients with skull fractures should follow the following points:

For patients with skull base fractures, follow the doctor's orders to closely observe changes in vital signs, detect cerebral hernia early, and perform surgical treatment in time. Those with skull base fractures and cerebrospinal fluid leakage should rest in bed. If the skull base fracture has cerebrospinal fluid leakage, a sterile towel should be placed under the pillow. All operations should be treated as a sterile wound to prevent infection. The supine position of patients with skull base fractures lies on the affected side to facilitate drainage. Skull base fractures and nasal leaks are prohibited from hand digging and blockage, coughing and sneezing can not be forced, anti-pollution has cerebrospinal fluid flowing back into the skull, causing intracranial infection and gas accumulation. Lumbar puncture is not allowed for patients with skull base fractures, except for those with intracranial infection. Patients with skull base fractures should keep the ears and nose clean, and clean the area daily with hydrogen peroxide and saline cotton balls. Skull base fractures involve the temporal bone rock and damage the auditory nerve. Patients' hearing loss, the nursing staff should be concerned and considerate of the patient, and strengthen life care. Severe brain contusion combined with nasal leakage, sputum suction from the nasal cavity is forbidden, and the nasal leakage does not stop, and various pipes cannot be inserted from the nasal cavity. In addition to giving control of medications when diabetes insipidus occurs due to a fracture of the middle cranial fossa floor and damage to the hypothalamus, sufficient drinking water should be provided.