Cervical Spine Fracture Evaluation

Injuries commonly associated with a flexion mechanism include the following:

• Simple wedge compression fracture without posterior disruption

• Flexion teardrop fracture

• Anterior subluxation

• Bilateral facet dislocation

• Clay shoveler fracture

• Anterior atlantoaxial dislocation

Simple wedge fracture

With a pure flexion injury, a longitudinal pull is exerted on the nuchal ligament complex that, because of its strength, usually remains intact. The anterior vertebral body bears most of the force, sustaining simple wedge compression anteriorly without any posterior disruption.

Radiographically, the anterior border of the vertebral body has diminished height and increased concavity along with increased density due to bony impaction (see the image below). The prevertebral soft tissues are swollen.

(A) Simple wedge fracture with a flexion mechanism of injury is stable. (B) Flexion teardrop fracture with a flexion mechanism is unstable.

The posterior column remains intact, making this a stable fracture that requires only use of a cervical orthosis for treatment.

Flexion teardrop fracture

A flexion teardrop fracture occurs when flexion of the spine, along with vertical axial compression, causes a fracture of the anteroinferior aspect of the vertebral body. This fragment is displaced anteriorly and resembles a teardrop (see the image below).

(A) Simple wedge fracture with a flexion mechanism of injury is stable. (B) Flexion teardrop fracture with a flexion mechanism is unstable.

For this fragment to be produced, significant posterior ligamentous disruption must occur. Since the fragment displaces anteriorly, a significant degree of anterior ligamentous disruption exists.

This injury involves disruption of all 3 columns, making this an extremely unstable fracture that frequently is associated with spinal cord injury. Initial management is application of traction with cervical tongs.

Anterior subluxation

Anterior subluxation in the cervical spine occurs when posterior ligamentous complexes (nuchal ligament, capsular ligaments, ligamenta flava, posterior longitudinal ligament) rupture. The anterior longitudinal ligament remains intact. No associated bony injury is seen.

Radiographically, the lateral view shows widening of interspinous processes, and anterior and posterior contour lines are disrupted in flexion views (see the image below). Since the anterior columns remain intact, this fracture is considered mechanically stable by definition.

Anterior subluxation with a flexion mechanism is stable in extension but potentially unstable in flexion.

Anterior subluxation is rarely associated with neurologic sequelae. Nevertheless, most authorities approach this injury as if it were potentially unstable because of the significant displacement that can occur with flexion, and very rare cases have associated neurologic deficit.

Bilateral facet dislocation

Bilateral facet dislocation is an extreme form of anterior subluxation that occurs when a significant degree of flexion and anterior subluxation causes ligamentous disruption to extend anteriorly, which causes significant anterior displacement of the spine at the level of injury. This injury involves the annulus fibrosus, the anterior longitudinal ligament, and the posterior ligamentous complex. At the level of injury (ie, the upper vertebrae), inferior articulating facets pass superior and anterior to the superior articulating facets of the lower involved vertebrae because of extreme flexion of the spine.

Radiographically, this is seen as displacement of more than half of the anteroposterior diameter of the vertebral body in the lateral view (see the image below).

Bilateral facet dislocation with a flexion mechanism is extremely unstable and can have an associated disk herniation that impinges on the spinal cord during reduction.

This is an extremely unstable condition and is associated with a high prevalence of spinal cord injuries. Initial management is closed reduction and traction with cervical tongs. A significant number of bilateral facet dislocations are accompanied by disk herniation. In patients with these injuries, further neurologic damage may occur if the injured disk retropulses into the canal during the application of cervical traction. Therefore, a careful neurologic examination should accompany closed reduction in these patients.

Clay shoveler fracture

Abrupt flexion of the neck, combined with a heavy upper body and lower neck muscular contraction, results in an oblique fracture of the base of the spinous process, which is avulsed by the intact and powerful supraspinous ligament. Fracture also occurs with direct blows to the spinous process or with trauma to the occiput that causes forced flexion of the neck.

Injury commonly is observed in a lateral view, since the avulsed fragment is readily evident (see the image below). Injury commonly occurs in lower cervical vertebrae; therefore, visualization of the C7-T1 junction in the lateral view is imperative. Injury also may be seen in the anteroposterior view as a vertically split appearance of the spinous process in the lower vertebrae.

Clay shoveler fracture. (A) Lateral view of this fracture caused by a flexion mechanism shows that it is stable and represents an avulsion fracture of the base of the spinous process near the supraspinous ligament. (B) Anteroposterior view shows the vertically split appearance of the spinous process.

Since injury involves only the spinous process, this fracture is considered stable and is not associated with neurologic impairment. Management involves only cervical immobilization with an orthotic device for comfort.

Anterior atlantoaxial dislocation

Atlantoaxial dislocation usually results from hyperextension trauma and is almost always accompanied by odontoid fracture and neurologic symptoms. In most cases, patients with atlantoaxial dislocation die instantly.[22]

Not only does chronic anterior atlantoaxial dislocation (AAD) result in myelopathy, but dislocation-related kyphosis results in cervical malalignment, which permanently affects neck function and patient-reported outcomes (PROs). Correction and reduction surgery can realign the cervical spine in patients with chronic AAD. The C1-C2 Cobb angle is an independent parameter correlated with improvement in PROs.[23]

Injuries commonly associated with a flexion-rotation mechanism include unilateral facet dislocation and rotary atlantoaxial dislocation.

Unilateral facet dislocation

Unilateral facet dislocation occurs when flexion, along with rotation, forces one inferior articular facet of an upper vertebra to pass superior and anterior to the superior articular facet of a lower vertebra, coming to rest in the intervertebral foramen (see the image below).

Unilateral facet dislocation. (A) Lateral view of this fracture caused by a flexion-rotation mechanism shows that it is stable. Anterior displacement of spine is less than one half of the diameter of a vertebral body. (B) Anteroposterior view shows disruption of a line connecting spinous processes at the level of the dislocation. (C) Oblique view shows that the expected tiling of the laminae is disrupted, and the dislocated superior articulating facet of the lower vertebra is seen projecting within the neural foramina.

Although the posterior ligament is disrupted, vertebrae are locked in place, making this injury stable.

Radiographically, the lateral view shows anterior displacement of the spine at the involved level of less than one half the diameter of the vertebral body. This is in contrast to the greater displacement seen with a bilateral facet dislocation. The anteroposterior view is useful in diagnosis of unilateral dislocation because it shows a disruption in the line connecting the spinous processes at the level of the dislocation (see the image below). The oblique view is also useful because it shows disruption of the typical shingles appearance at the level of the involved vertebra. The dislocated superior articulating facet of the lower vertebra is seen projecting within the neural foramina.

Unilateral facet dislocation. (A) Lateral view of this fracture caused by a flexion-rotation mechanism shows that it is stable. Anterior displacement of spine is less than one half of the diameter of a vertebral body. (B) Anteroposterior view shows disruption of a line connecting spinous processes at the level of the dislocation. (C) Oblique view shows that the expected tiling of the laminae is disrupted, and the dislocated superior articulating facet of the lower vertebra is seen projecting within the neural foramina.

The injury seldom is associated with neurologic deficits. The orthopedic consultant performs initial management, applying cervical traction to attempt closed reduction.

Rotary atlantoaxial dislocation

This injury is a specific type of unilateral facet dislocation.

Radiographically, the odontoid view shows asymmetry of the lateral masses of C1 with respect to the dens, along with unilateral magnification of a lateral mass of C1 (wink sign). However, since the atlantoaxial joint permits flexion, extension, rotation, and lateral bending, radiographic asymmetry is produced when the head is tilted laterally or rotated, or if a slightly oblique odontoid view is obtained despite perfect head positioning. To confirm true dislocation, basilar skull structures (jugular foramina) should appear symmetric in the presence of the findings described above.

This injury is considered unstable because of its location.

Injuries commonly associated with an extension mechanism include hangman fracture, extension teardrop fracture, fracture of the posterior arch of C1 (posterior neural arch fracture of C1), and posterior atlantoaxial dislocation.

Hangman fracture (traumatic spondylolisthesis of C2)

The name of this injury is derived from the typical fracture that occurs after hangings. It is commonly caused by motor vehicle collisions and entails bilateral fractures through the pedicles of C2 due to hyperextension.

Radiographically, a fracture line should be evident extending through the pedicles of C2 along with obvious disruption of the spinolaminar contour line (see the image below).

Hangman fracture caused by an extension mechanism is unstable. Fracture line is evident in the lateral projection extending through pedicles of C2, along with disruption of the spinolaminar line. Sometimes, this fracture is associated with unilateral or bilateral facet dislocation, which makes it highly unstable.

Although considered an unstable fracture, hangman fracture seldom is associated with spinal injury, since the anteroposterior diameter of the spinal canal is greatest at this level and the fractured pedicles allow decompression. When associated with unilateral or bilateral facet dislocation at the level of C2, this particular type of hangman fracture is unstable and has a high rate of neurologic complications that require immediate referral for cervical traction to reduce the facet dislocation. All other types of hangman fracture can be managed initially with a cervical orthotic device.

Extension teardrop fracture

As with flexion teardrop fracture, extension teardrop fracture manifests with a displaced anteroinferior bony fragment. This fracture occurs when the anterior longitudinal ligament pulls fragment away from the inferior aspect of the vertebra because of sudden hyperextension. The fragment is a true avulsion, in contrast to the flexion teardrop fracture, in which the fragment is produced by compression of the anterior vertebral aspect due to hyperflexion.

This fracture is common after diving accidents and tends to occur at lower cervical levels. It also may be associated with the central cord syndrome due to buckling of the ligamenta flava into the spinal canal during the hyperextension phase of injury.

This injury is stable in flexion but highly unstable in extension. Initial management is avoidance of iatrogenic extension and cervical traction with tongs.

Fracture of the posterior arch of C1 fracture (posterior neural arch fracture)

This fracture occurs when the head is hyperextended and the posterior neural arch of C1 is compressed between the occiput and the strong, prominent spinous process of C2, causing the weak posterior arch of C1 to fracture (see the image below).

(A) Fracture of the posterior arch of C1 fracture caused by an extension mechanism is stable. Lateral projection shows a fracture line through the posterior neural arch without widening predental space. An odontoid view must be obtained to differentiate this benign fracture from a Jefferson fracture. (B) Jefferson fracture caused by a vertical (axial) compression mechanism is unstable. This fracture of all aspects of the C1 ring is associated with possible disruption of the transverse ligament of the atlas. Lateral projection may show a widened predental space and a fracture through the posterior arch of C1. Odontoid view shows displacement of the lateral masses of C1, allowing distinction of this fracture from a simple fracture of the posterior neural arch of C1.

Radiographically, the lateral projection shows a fracture line through the posterior neural arch. The odontoid view fails to show any displacement of the lateral masses of C1 with respect to articular pillars of C2—a finding that distinguishes this fracture from a Jefferson fracture.

The transverse ligament and the anterior arch of C1 are not involved, making this fracture stable. Initial management involves differentiation of this benign fracture from a Jefferson fracture. Once this is accomplished, only use of a cervical orthosis is required.

Posterior atlantoaxial dislocation

In general, atlantoaxial dislocation is rare because of the stability of the C1-C2 complex. Traumatic atlantoaxial dislocations are usually anterior and accompanied by odontoid fractures. Complete posterior dislocation without associated fracture is even more rare than posterior atlantoaxial dislocations.[24]

Closed manual reduction under C-arm fluoroscopy is an easy and effective method used to assess posterior atlantoaxial dislocation. The integrity of the transverse ligament can be confirmed by C-arm fluoroscopy through the atlantoaxial dynamic test after reduction. Pedicle screw internal fixation via the posterior approach can provide sufficient stability.[25]

Injuries commonly associated with a vertical compression mechanism include Jefferson fracture (burst fracture of the ring of C1), burst fracture (dispersion, axial loading), atlas fracture, and isolated fracture of the lateral mass of C1 (pillar fracture).

Jefferson fracture (burst fracture of the ring of C1)

Jefferson fracture is caused by a compressive downward force that is transmitted evenly through the occipital condyles to the superior articular surfaces of the lateral masses of C1. The process displaces the masses laterally and causes fractures of the anterior and posterior arches, along with possible disruption of the transverse ligament. Quadruple fracture of all 4 aspects of the C1 ring occurs.

Radiographically, the fracture is characterized by bilateral lateral displacement of the articular masses of C1. The odontoid view shows unilateral or bilateral displacement of the lateral masses of C1 with respect to the articular pillars of C2; this finding differentiates it from a simple fracture of the posterior neural arch of C1 (see the image below).

(A) Fracture of the posterior arch of C1 fracture caused by an extension mechanism is stable. Lateral projection shows a fracture line through the posterior neural arch without widening predental space. An odontoid view must be obtained to differentiate this benign fracture from a Jefferson fracture. (B) Jefferson fracture caused by a vertical (axial) compression mechanism is unstable. This fracture of all aspects of the C1 ring is associated with possible disruption of the transverse ligament of the atlas. Lateral projection may show a widened predental space and a fracture through the posterior arch of C1. Odontoid view shows displacement of the lateral masses of C1, allowing distinction of this fracture from a simple fracture of the posterior neural arch of C1.

The lateral projection usually reveals a striking amount of prevertebral soft tissue edema.

When displacement of the lateral masses is greater than 6.9 mm, complete disruption of the transverse ligament has occurred and immediate referral for cervical traction is warranted. If displacement is less than 6.9 mm, the transverse ligament is still competent and neurologic injury is unlikely.

Burst fracture of the vertebral body (dispersion, axial loading)

When downward compressive force is transmitted to lower levels in the cervical spine, the body of the cervical vertebra can shatter outward, causing a burst fracture. This fracture involves disruption of the anterior and middle columns, with a variable degree of posterior protrusion of the latter.

Radiographically, this fracture is evidenced by a vertical fracture line in the frontal projection and by comminution and protrusion of the vertebral body anteriorly and posteriorly with respect to the contiguous vertebrae in the lateral view (see the image below).

Burst fracture of vertebral body caused by a vertical (axial) compression mechanism is stable mechanically and involves disruption of the anterior and middle columns, with variable degree of protrusion of the latter. This middle column posterior protrusion may extend into the spinal canal and be associated with an anterior cord syndrome.

Posterior protrusion of the middle column may extend into the spinal canal and can be associated with anterior cord syndrome. Burst fractures always require an axial CT scan or MRI to document the extent of middle column retropulsion.

Initial management of burst fractures with a loss in height greater than 25%, retropulsion, or neurologic deficit is accomplished by applying traction with cervical tongs. When none of those problems exist, the fracture is considered stable.

Atlas fracture

Atlas fracture occurs in 3-13% of all cervical spinal injuries and is often associated with other injuries. Factors associated with concomitant transverse ligament disruption and vertebral artery injury remain underexamined. In patients with atlas fractures, vertebral artery injury and transverse ligament disruption are associated with each other. Mechanism of injury, fracture type, and intoxication at the time of injury are associated with vertebral artery injury, and atlantodental interval and lateral mass displacement are associated with MRI-confirmed injury to the transverse ligament.[26]

Isolated fracture of the lateral mass of C1 (pillar fracture)

C1 fractures with an intact transverse ligament are usually treated conservatively. Patients who present with progressive diastasis of bone fragments and progressive articular subluxation mainly attributed to progressive lengthening of transverse ligament (TAL) fibers can be treated with a C1 "C-clamp" fusion. Simple lateral mass fixation with the C-clamp technique is a reasonable option in cases of isolated C1 fracture in patients in whom conservative management has failed.[27]

Upper cervical spine (occiput to C2) injuries

Injuries at the upper cervical level are considered unstable because of their location. Nevertheless, since the diameter of the spinal canal is greatest at the level of C2, spinal cord injury from compression is the exception rather than the rule. Incompletely understood mechanisms or a combination of mechanisms usually produce injuries encountered at this level.

Injuries commonly include fracture of the atlas, atlantoaxial subluxation, odontoid fracture, and hangman fracture (see Extension Injury. above). Less common injuries include occipital condyle fracture, atlanto-occipital dislocation, atlantoaxial rotary subluxation (see Flexion-Rotation Injury, above), and C2 lateral mass fracture.

Atlas (C1) fractures

Four types of atlas fractures (I, II, III, IV) result from impaction of the occipital condyles on the atlas, causing single or multiple fractures around the ring. The first 2 types of atlas fracture are stable and include isolated fractures of the anterior and posterior arch of C1 (posterior arch fracture is described under Extension Injury). Anterior arch fractures usually are avulsion fractures from the anterior portion of the ring and have a low morbidity and little clinical significance. The third type of atlas fracture is a fracture through the lateral mass of C1. Radiographically, asymmetric displacement of the mass from the rest of the vertebra is seen in the odontoid view. This fracture also has a low morbidity and little clinical significance. The fourth type of atlas fracture is the burst fracture of the ring of C1 and is known as a Jefferson fracture (discussed under Vertical [Axial] Compression Injury, above). This is the most significant type of atlas fracture from a clinical standpoint because it is associated with neurologic impairment.

Initial management of types I, II, and III atlas fractures consists of placement of a cervical orthosis. Type IV fracture, or Jefferson fracture, is managed with cervical traction.

Atlantoaxial subluxation

When flexion occurs without a lateral or rotatory component at the upper cervical level, it can cause anterior dislocation at the atlantoaxial joint if the transverse ligament is disrupted. Because this joint is near the skull, shearing forces also play a part in the mechanism causing this injury, as the skull grinds the C1-C2 complex in flexion. Since the transverse ligament is the main stabilizing force of the atlantoaxial joint, this injury is unstable. Neurologic injury may occur from cord compression between the odontoid and the posterior arch of C1.

Radiographically, this injury is suspected if the predental space is greater than 3.5 mm (5 mm in children); axial CT is used to confirm the diagnosis. These injuries may require fusion of C1 and C2 for definitive management.

Atlanto-occipital dislocation

When severe flexion or extension exists at the upper cervical level, atlanto-occipital dislocation may occur. Atlanto-occipital dislocation involves complete disruption of all ligamentous relationships between the occiput and the atlas. Death usually occurs immediately from stretching of the brainstem, which causes respiratory arrest.

Radiographically, disassociation between the base of the occiput and the arch of C1 is seen. Cervical traction is absolutely contraindicated, since further stretching of the brainstem can occur.

Odontoid process fractures

The 3 types of odontoid process fractures are classified based on the anatomic level at which the fracture occurs (see the image below).

Odontoid fractures. (A) Type I odontoid fracture represents an avulsion of the tip of the dens at the insertion site of the alar ligament. Although mechanically stable, it is associated with life-threatening atlanto-occipital dislocation. (B) Type II odontoid fracture is a fracture at the base of the dens. This is the most common type of odontoid fracture. (C) With type III odontoid fracture, the fracture line extends into the body of the axis.

Type I odontoid fracture is an avulsion of the tip of the dens at the insertion site of the alar ligament. Although a type I fracture is mechanically stable, it often is seen in association with atlanto-occipital dislocation and must be ruled out because of this potentially life-threatening complication.

Type II odontoid fracture occurs at the base of the dens and are the most common odontoid fractures. This type is associated with a high prevalence of nonunion due to the limited vascular supply and the small area of cancellous bone.

Type III odontoid fracture occurs when the fracture line extends into the body of the axis. Nonunion is not a major problem with these injuries because of a good blood supply and the greater amount of cancellous bone.

With types II and III fractures, the fractured segment may be displaced anteriorly, laterally, or posteriorly. Since posterior displacement of segment is more common, the prevalence of spinal cord injury is as high as 10% with these fractures.

Initial management of a type I dens fracture is use of a cervical orthosis. Manage types II and III fractures by applying traction with cervical tongs.

Occipital condyle fracture

Occipital condyle fractures are caused by a combination of vertical compression and lateral bending. Avulsion of the condylar process or a comminuted compression fracture may occur secondary to this mechanism. These fractures are associated with significant head trauma and usually are accompanied by cranial nerve deficits.

Radiographically, they are difficult to delineate, and axial CT may be required to identify them.

These mechanically stable injuries require only orthotic immobilization for management, and most heal uneventfully. These fractures are significant because of the injuries that usually accompany them.

Column disruption may lead to mechanical instability of the cervical spine. The degree of instability depends on several factors that may translate into neurologic disability secondary to spinal cord compression. There is a full spectrum of cervical injuries with varying degrees of clinical importance, from the clinically insignificant to the potentially disastrous. As many as 39% of cervical fractures have some degree of associated neurologic deficit.

The risk of neurologic injury, secondary to spinal injury, increases with degenerative changes related to aging, arthritic conditions (rheumatoid arthritis, ankylosing spondylitis), spinal stenosis, spina bifida, and os odontoideum, as well as the specific mechanism and location of the injury.

Trafton has ranked specific cervical injuries based on their degree of mechanical instability.[28] The list below ranks cervical spine injuries in order of instability (most to least unstable):

• Rupture of the transverse ligament of the atlas

• Fracture of the dens (odontoid fracture)

• Burst fracture with posterior ligamentous disruption (flexion teardrop fracture)

• Bilateral facet dislocation

• Burst fracture without posterior ligamentous disruption

• Hyperextension fracture dislocation

• Hangman fracture

• Extension teardrop (stable in flexion)

• Jefferson fracture (burst fracture of the ring of C1)

• Unilateral facet dislocation

• Anterior subluxation

• Simple wedge compression fracture without posterior disruption

• Pillar fracture

• Fracture of the posterior arch of C1

• Spinous process fracture (clay shoveler fracture)

Common presentations of cervical spine fracture include the following:

• Posterior neck pain on palpation of spinous processes

• Limited range of motion associated with pain

• Weakness, numbness, or paresthesias along affected nerve roots

Clinical evaluation of the cervical spine in a patient with blunt trauma is unreliable. In a study of surgical residents' ability to predict cervical injuries on the basis of clinical examination alone, sensitivity and specificity were 46% and 94%, respectively. Because of these limitations and the potential for catastrophic morbidity if injury is missed, most patients with complex blunt trauma seen in the ED undergo radiographic evaluation before clearance, with some exceptions.

Common findings on physical examination in cervical spine injury include the following:

• Spinal shock

  • Flaccidity

  • Areflexia

  • Loss of anal sphincter tone

  • Fecal incontinence

  • Priapism

  • Loss of bulbocavernosus reflex

• Neurogenic shock

  • Hypotension

  • Paradoxical bradycardia

  • Flushed, dry, and warm peripheral skin

• Autonomic dysfunction

  • Ileus

  • Urinary retention

  • Poikilothermia

Motor vehicle collisions and falls account for 50% and 20% of cervical spine injuries, respectively. Studies have shown that the impact velocity at the time of a motor vehicle collision,[29, 30]  airbag deployment on unrestrained drivers,[31, 32]  drivers aged 65 years or older, and rollover mechanisms[33] all significantly increase the likelihood of a cervical spine injury.

Sports-related activities account for 15%. The remaining injuries are attributed to interpersonal violence. The following athletic activities have the highest incidence of associated cervical spine injuries. Participants in these events should be considered at high risk:

• Diving

• Equestrian activities

• Football

• Gymnastics

• Skiing

• Hang gliding

Penetrating trauma rarely causes cervical spine fracture but may result in significant neurologic deficits.[34] In one study of 144 cervical gunshot wounds, 40 were associated with neurologic deficits.[35]

Spinal shock

Severe spinal cord injury may cause a concussive injury of the spinal cord termed spinal shock syndrome.

Spinal shock manifests as distal areflexia of a transient nature that may last from a few hours to weeks. Initially, the patient experiences a flaccid quadriplegia along with areflexia. Segmental reflexes start to return usually within 24 hours as spinal shock starts to resolve. At that point, flaccid quadriplegia changes to spastic paralysis.

Eventually, total resolution can be expected.

Neurogenic shock

Neurogenic shock is spinal shock that causes vasomotor instability because of loss of sympathetic tone.

Patients with neurogenic shock are hypotensive but have paradoxical bradycardia.

Flushed, dry, and warm peripheral skin (in contrast to findings with hypovolemic or cardiogenic shock) may be present. Other signs of autonomic dysfunction include ileus, urinary retention, and poikilothermia.

Loss of anal sphincter tone with fecal incontinence and priapism suggest spinal shock. Return of the bulbocavernosus reflex heralds resolution of spinal shock.

Complete and incomplete cord syndromes

Besides spinal shock, complete and incomplete spinal cord syndromes may occur.

Spinal shock mimics a complete spinal cord lesion. Emergency physicians should wait until spinal shock resolves to make an accurate estimate of the patient's prognosis.

Incomplete cord syndromes are described and include anterior spinal cord syndrome, central spinal cord syndrome, Brown-Séquard syndrome, and less frequent cord syndromes at high cervical levels (ie, Horner syndrome, posteroinferior cerebellar artery syndrome).

The prognosis of a patient with a complete lesion, after spinal shock subsides, is permanent paraplegia.

Patients with an incomplete lesion (partial motor or sensory function) can expect to regain some degree of function.

Anterior spinal cord syndrome

Anterior spinal cord syndrome involves complete motor paralysis and loss of temperature and pain perception distal to the lesion. Since posterior columns are spared, light touch, vibration, and proprioceptive input are preserved.

This syndrome is caused by compression of the anterior spinal artery, which results in anterior cord ischemia or direct compression of the anterior cord. It is associated with burst fractures of the spinal column with fragment retropulsion caused by axial compression.

Central spinal cord syndrome

This syndrome is caused by damage to the corticospinal tract.

It is characterized by weakness, greater in the upper extremities than in the lower extremities and more pronounced in the distal aspect of the extremity.

This syndrome usually is associated with a hyperextension injury in patients with spondylosis or congenital stenosis of the cervical canal.

Extension of the cervical spine, causing buckling of the ligamentum flavum into the spinal cord, is believed to cause central spinal cord syndrome.

Brown-Séquard syndrome

This syndrome involves injury to only 1 side of the spinal cord.

It causes paralysis, loss of vibration sensation, and loss of proprioceptive input ipsilaterally, with contralateral loss of pain and temperature perception because of involvement of posterior columns and spinothalamic tracts on the same side.

It is associated with hemisection of the spinal cord from penetrating trauma; however, it can be caused by a lateral mass fracture of a cervical vertebra.

High cervical spinal cord syndromes

These syndromes are associated with damage to the spinal tract of the trigeminal nerve in the high cervical region.

A characteristic onion-skin pattern of anesthesia in the face may occur.

Horner syndrome

Horner syndrome manifests as ptosis, miosis, and anhidrosis.

It results from damage to the cervical sympathetic chain.

Posteroinferior cerebellar artery syndrome

A diverse constellation of symptoms, including dysphagia, dysphonia, hiccups, vertigo, vomiting, or cerebellar ataxia, may occur.

Any of the high cervical cord syndromes may result from direct injury to the upper cervical level and/or cervicomedullary junction.

Vertebral artery occlusion from dislocation or hyperextension of the cervical column also can produce these syndromes.

Craniofacial injuries

An association between significant craniofacial injuries and cervical spine fractures seems intuitively logical, yet several retrospective series do not support this assumption.

A retrospective review of 2555 patients with significant facial injuries found that only 1.3% had concomitant cervical spine injury.[36] In a smaller series, 1272 patients with significant craniocerebral injury had only a 1.8% prevalence of cervical injuries.[37] A review of 1050 patients admitted with facial fractures found only a 4% prevalence of an associated cervical injury, even though the prevalence of associated head injuries was 85%.[38] These and other series indicate that closed head injuries and facial fractures may not significantly increase the risk of concomitant cervical spine injury.

A larger retrospective study suggests there is increased risk (4.5% vs 1.1%) of cervical spine injury with craniocerebral (but not with facial) injuries.[39]

Regardless of the results, none of these retrospective studies suggests decreasing standard care, such as ordering radiographs to find cervical spine injuries in trauma patients.

Radiographic evaluation is indicated in the following:

• Patients who exhibit neurologic deficits consistent with a cord lesion

• Patients with an altered sensorium from head injury or intoxication

• Patients who complain about neck pain or tenderness

• Patients who do not complain about neck pain or tenderness but have significant distracting injuries

The literature has examined the need for C-spine imaging in patients at low risk for unstable fracture or ligamentous injury. The Canadian C-Spine Rules (CCR) and the National Emergency X-Radiography Utilization Group (NEXUS) criteria allow clinicians to "clear" low-risk patients of C-spine injury, obviating the need for radiography. Additionally, a model was developed specifically for injured children.[2, 9, 18, 40]

To be clinically cleared using the CCR, a patient must be alert (GCS 15), must not be intoxicated, and must not have a distracting injury (eg, long bone fracture, large laceration). The patient can be clinically cleared provided the following criteria are met:

• The patient is not high risk (age >65 y or dangerous mechanism or paresthesias in extremities).

• A low risk factor that allows safe assessment of range of motion exists. This includes simple rear end motor vehicle collision, seated position in the ED, ambulation at any time post trauma, delayed onset of neck pain, and absence of midline cervical spine tenderness.

• The patient is able to actively rotate the neck 45 degrees left and right.

The NEXUS criteria state that a patient with suspected C-spine injury can be cleared provided the following are true:

• No posterior midline cervical spine tenderness is present.

• No evidence of intoxication is present.

• The patient has a normal level of alertness.

• No focal neurologic deficit is present.

• The patient does not have a painful distracting injury.

Both studies have been prospectively validated as being sufficiently sensitive to rule out clinically significant C-spine pathology. The CCR were shown to be more sensitive than NEXUS criteria (99.4% sensitive vs 90.7%), and rates of radiography were lower with CCR (55.9% vs 66.6%).[41] Debate continues as to which criteria are more useful and are easier to apply.

A survey of 76 trauma care physicians found that altered mental state, intoxication, and distracting injury were the most important contraindications to cervical spine clearance in children. Regarding imaging, 54% considered adequate plain imaging to be 3-view cervical spine radiographs (anterior-posterior, lateral, and odontoid), whereas 30% considered CT to be the most sensitive modality for detecting unstable cervical spine injuries.[42]

A standard trauma series is composed of 5 views: cross-table lateral, swimmer's, oblique, odontoid, and anteroposterior.

According to the World Federation of Neurosurgical Societies (WFNS), angiography has been considered the gold standard for vertebral artery injury after cervical trauma, but it is difficult and time consuming to perform. CTA, using multislice machines, has been shown to identify the injury with a sensitivity of 100%.[43]

Cross-table lateral view

Approximately 85-90% of cervical spine injuries are evident in the lateral view, making this the most useful view from a clinical standpoint.

A technically acceptable lateral view shows all 7 vertebral bodies and the cervicothoracic junction. One should approach analysis of this view methodically to avoid missing significant pathology.

Check alignment of the cervical spine by following 3 imaginary contour lines. (See the image below.)

(A) Normal lateral projection shows the relationships of anterior, posterior, and spinolaminar lines and prevertebral spaces. (B) Normal oblique projection shows the normal appearance of the laminae as shingles on a roof forming a regular elliptical curve with equal interlaminar spaces.

The first line connects the anterior margins of all vertebrae and is referred to as the anterior contour line. The second line should connect the posterior aspects of all vertebrae in a similar way and is referred to as the posterior contour line. The third line should connect the bases of the spinous processes and is referred to as the spinolaminar contour line.

Each of these lines should form a smooth lordotic curve. Suspect bony or ligamentous injury if disruption is seen in the contour lines.

An exception occurs in young children, who, because of immature muscular development, may have a benign pseudosubluxation in the upper cervical spine. An imaginary straight line should connect the points bisecting the base of the spinous processes of C1, C2, and C3. In pseudosubluxation, these imaginary points should not be displaced more than 2 mm in front of or behind the straight line.

Check individual vertebrae thoroughly for obvious fracture or changes in bone density. Areas of decreased bone density are seen in patients with osteoporosis, osteomalacia, or osteolytic lesions and may represent weak areas predisposed to injury. Areas of increased bony density may be seen with osteoblastic lesions or may represent compression fractures of an acute nature.

Look for soft tissue changes in predental and prevertebral spaces. The predental space, also known as the atlantodental interval, is the distance between the anterior aspect of the odontoid and the posterior aspect of the anterior arch of C1. This space should be no larger than 3 mm in an adult and 5 mm in a child. Suspect transverse ligament disruption if these limits are exceeded.

Prevertebral space extends between the anterior border of the vertebra to the posterior wall of the pharynx in the upper vertebral level (C2-C4) or to the trachea in the lower vertebral level (C6).

At the level of C2, prevertebral space should not exceed 7 mm.

At the level of C3 and C4, it should not exceed 5 mm, or it should be less than half the width of the involved vertebrae.

At the level of C6, the prevertebral space is widened by the presence of the esophagus and the cricopharyngeal muscle. At this level, the space should be no larger than 22 mm in adults or 14 mm in children younger than 15 years.

Children younger than 24 months may exhibit a physiologic widening of the prevertebral space during expiration; therefore, images should be obtained in small children during inspiration to assess prevertebral space adequately.

If the prevertebral space is widened at any level, a hematoma secondary to a fracture is the most likely diagnosis.

Check for fanning of the spinous processes. This is evident as an exaggerated widening of the space between 2 spinous process tips and suggests posterior ligamentous disruption.

Check for an abrupt change in angulation greater than 11 degrees at a single interspace. This suggests bony injury with possible ligamentous involvement.

Swimmer's view

Occasionally, it is impossible to fully visualize all 7 cervical vertebrae and, more important, the cervicothoracic junction in a true lateral image.

Failure to fully visualize these areas has resulted in patient morbidity and successful malpractice litigation against emergency physicians.

A swimmer's view, or a transaxillary view, adequately exposes these areas for scrutiny.

Oblique view

This view also is considered a laminar view because most pathologic conditions assessed on it manifest with some disruption in the normal overlapping appearance of the vertebral laminae.

The normal structural appearance of the laminae is described as shingles on a roof, forming a regular elliptical curve with equal interlaminar spaces.

If interlaminar space between 2 continuous laminae is increased, suspect subluxation of the involved vertebrae.

Similarly, if the expected tiling of shingles is disrupted, suspect a unilateral facet dislocation.

A posterior laminar fracture should be evident as disruption of the body of a single shingle.

Odontoid view

This view is used to evaluate an area that is difficult to visualize in the cross-table lateral view because of shadow superimposition.

The most important structural relationship to evaluate in this view is alignment of the lateral masses of C1 with respect to the odontoid process.

Masses should be bilaterally symmetric with the dens and odontoid process and must be checked for fractures or lateral displacement.

Assess symmetry of the interspace between C1 and C2.

Anteroposterior view

This is the least useful view from a clinical standpoint.

A straight line should connect the spinous processes bisecting the cervical spine. If this is not seen, consider a rotation injury (ie, unilateral facet dislocation). Also consider a clay shoveler fracture if a spinous process appears vertically split.

The advent of readily available multidetector computed tomography (CT) has supplanted the use of plain radiography at many centers. The literature supports CT as more sensitive, with lower rates of missed primary and secondary injuries.[15] One series found 36% of patients with one injury on plain radiography had a second injury seen on CT only. Of these patients, 27% had a noncontiguous, anatomically distinct second injury. The same views generated by plain radiography (AP, lateral, open mouth) are generated via CT. These results are cause to reconsider guidelines for implementation of CT as a primary diagnostic test. If plain radiograph findings are negative but clinical suspicion for fracture is high, films should be followed by CT.

One study determined that CT of the cervical spine may be overused for ground-level falls. The authors suggested that, in such cases, consistent application of clinical decision rules (eg, NEXUS, CCR) would reduce both costs and radiation dose exposure if applied across all level I trauma centers.[44]

The American College of Orthopaedic Surgeons now recommends routine cervical spine screening via CT scan instead of plain radiography. Low-dose multidetector CT scanning has been found to be as sensitive and specific as standard dose multidetector CT scans.[45, 46]

Soft tissue injury (ie, unstable ligamentous injury) has traditionally been evaluated by flexion-extension views. Magnetic resonance imaging (MRI) is less dangerous and more sensitive for soft tissue injury than radiography. Limited availability makes familiarity with flexion-extension views essential.[47, 48]

Multidetector-row CT (MDCT) and MRI can be  complementary, and both may be necessary to identify injuries and to determine proper management.[49]

In a 5-year retrospective study of polytrauma patients who underwent MDCT, signs of significant ligament injury on CT at the craniocervical junction were identified as increased basion dens interval and widened facet joints. In the subaxial cervical spine, more than 50% subluxation of a facet joint and obscured posterior paraspinal fat pad were indicators of significant ligament injury.[6]

An association between cervical spine fractures and thoracolumbar spine fractures has been identified in victims of motor vehicle collisions (MVCs). Based on this finding, it is recommended that any MVC patient found to have a cervical spine fracture should undergo complete spine imaging.[4]

One study supported findings in the literature that C1-C3 spine injuries have an increased association with vertebral artery injury. The authors noted, however, that CT angiography of the head and neck ordered off protocol had a low likelihood of being positive and that strict adherence to protocols for CT angiography of the head and neck can reduce costs and decrease unnecessary exposure to radiation and contrast medium.[50]

In a study by Goode et al, the National Emergency X-Radiography Utilization Study (NEXUS) criteria (NC) were compared with computed tomography (CT) as the gold standard to evaluate cervical spine (C-spine) fractures in elderly blunt trauma patients. According to findings, the authors suggested that NEXUS criteria are not an appropriate assessment tool when applied to severe blunt trauma patients, particularly in the elderly population, who have more missed injures than younger patients. They concluded that CT should be used in all blunt trauma patients regardless of whether they meet NEXUS criteria.[51]

Small and associates explored the use of a conventional neural network for CT cervical spine fracture detection and found that the convolutional neural network holds promise for both prioritizing worklists and assisting radiologists in cervical spine fracture detection on CT. Clinicians must gain an understanding of the strengths and weaknesses of the convolutional neural network before they can successfully incorporate it into clinical practice. Further refinements in sensitivity will improve the diagnostic usefulness of the convolutional neural network.[52]

A retrospective cross-sectional study sought to develop a clinical tool to identify patients who must undergo CT for evaluation of cervical spine fracture when treated at a hospital in which CT scanning is not available. Diagnostic imaging in developing countries has limitations. Also, CT scanning is not universally available 24 hours a day and is not cost-effective. This study included patients over 16 years of age with suspected cervical spine injury who underwent CT scanning in the ED. Study authors viewed independent factors (ie, high-risk mechanism of injury, paraparesis, paresthesia, limited range of motion of the neck, and associated chest or facial injury) as good predictors of C-spine fracture and developed predictive model and prediction scores via multivariable logistic regression analysis. Researchers concluded that patients with a clinical prediction score of 1 or greater should undergo CT for evaluation of cervical spine fracture.[53]

CCR and NEXUS

The Canadian C-Spine Rules (CCR) and the National Emergency X-Radiography Utilization Group (NEXUS) criteria allow clinicians to "clear" low-risk patients of C-spine injury, obviating the need for radiography. Additionally, a model was developed specifically for injured children.[2, 40]

To be clinically cleared using CCR, a patient must be alert (GCS 15), must not be intoxicated, and must not have a distracting injury (eg, long bone fracture, large laceration). The patient can be clinically cleared provided the following apply:

• The patient is not high risk (age >65 yr or dangerous mechanism or paresthesias in extremities).

• A low risk factor exists that allows safe assessment of range of motion. This includes simple rear end motor vehicle collision, seated position in the ED, ambulation at any time post trauma, delayed onset of neck pain, and absence of midline cervical spine tenderness.

• The patient is able to actively rotate the neck 45 degrees left and right.

The NEXUS criteria state that a patient with suspected C-spine injury can be cleared provided the following are true:

• No posterior midline cervical spine tenderness

• No evidence of intoxication

• Normal level of alertness

• No focal neurologic deficit

• No painful distracting injury

Both studies have been prospectively validated as being sufficiently sensitive to rule out clinically significant C-spine pathology. The CCR were shown to be more sensitive than the NEXUS criteria (99.4% sensitive vs 90.7%), and rates of radiography were lower with the CCR (55.9% vs 66.6%).[41] Debate continues as to which criteria are more useful and are easier to apply.

ACOS

The American College of Orthopaedic Surgeons now recommends routine cervical spine screening via CT scan instead of plain radiography. Low-dose multidetector CT scanning has been found to be as sensitive and specific as standard dose multidetector CT scans.[45, 46]

ASIA

The American Spinal Injury Association defines spinal cord injury as follows[17, 54] :

• A = Complete. No sensory or motor function is preserved in sacral segments S4-5.
• B = Sensory Incomplete. Sensory but not motor function is preserved below the neurologic level and includes the sacral segments S4-5 (light touch or pin prick at S4-5 or deep anal pressure) AND no motor function is preserved more than 3 levels below the motor level on either side of the body.
• C = Motor Incomplete. Motor function is preserved at the most caudal sacral segments for voluntary anal contraction (VAC) OR the patient meets the criteria for sensory incomplete status (sensory function preserved at the most caudal sacral segments [S4-S5] by LT [light touch], PP [pinprick], or DAP [deep anal pressure]) and has some sparing of motor function more than 3 levels below the ipsilateral motor level on either side of the body. (This includes key or non-key muscle functions to determine motor incomplete status.) For AIS C – less than half of key muscle functions below the single neurologic level of injury (NLI) have a muscle grade ≥3.
• D = Motor Incomplete. Motor incomplete status as defined above, with at least half (half or more) of key muscle functions below the single NLI having a muscle grade ≥3.
• E = Normal. If sensation and motor function as tested with the INTERNATIONAL STANDARDS FOR NEUROLOGICAL CLASSIFICATION OF SPINAL CORD INJURY (ISNCSCI) are graded as normal in all segments, and if the patient had prior deficits, the AIS grade is E. Someone without an initial SCI does not receive an AIS grade.

WFNS

According to the World Federation of Neurosurgical Societies (WFNS), angiography has been considered the gold standard for vertebral artery injury after cervical trauma, but it is difficult and time consuming to perform. CTA, using multislice machines, has been shown to identify the injury with a sensitivity of 100%.[43]  

ACR

According to the American College of Radiology (ACR), CT is preferred over radiographs for initial assessment of spinal trauma; CT angiography and MR angiography are both acceptable in assessment of cervical vascular injury; MRI is preferred over CT myelography for assessing neurologic injury in the setting of spinal trauma; and MRI is usually appropriate when there is concern about ligament injury or when screening obtunded patients for cervical spine instability.[1]

The ACR has published the following specific recommendations[1] :

• Imaging is not recommended for the initial imaging of patients ≥16 yr and < 65 yr with suspected acute blunt cervical spine trauma when imaging is not indicated by NEXUS or CCR clinical criteria and the patient meets low-risk criteria.
• CT of the cervical spine without IV contrast is usually appropriate for the initial imaging of patients ≥16 yr with suspected acute blunt trauma of the cervical spine when imaging is indicated by NEXUS or CCR clinical criteria.
• MRI of the cervical spine without IV contrast is usually appropriate as the next imaging study for patients ≥16 yr with suspected acute blunt trauma of the cervical spine and confirmed or suspected cervical spinal cord or nerve root injury, with or without traumatic injury identified on cervical CT.
• CT of the cervical spine without IV contrast and MRI of the cervical spine without IV contrast are usually appropriate for patients ≥16 yr with acute cervical spine injury detected on radiographs and for treatment planning in cases of a mechanically unstable spine. These procedures are complementary in the assessment of unstable spine injuries.
• CTA of the head and neck with IV contrast or MRA of the neck without and with IV contrast is usually appropriate as the next imaging study for patients ≥16 yr with suspected acute blunt trauma of the cervical spine and clinical or imaging findings suggesting arterial injury with or without positive cervical spine CT. These procedures are equivalent alternatives.
• MRI of the cervical spine without IV contrast is usually appropriate as the next imaging study after CT of the cervical spine without IV contrast for obtunded patients ≥16 yr with suspected acute blunt trauma of the cervical spine and no traumatic injury identified on cervical spine CT.
• MRI of the cervical spine without IV contrast is usually appropriate as the next imaging study after CT of the cervical spine without IV contrast for patients ≥16 yr with suspected acute blunt trauma of the cervical spine and clinical or imaging findings suggesting ligamentous injury.
• CT of the cervical spine without IV contrast, MRI of the cervical spine without IV contrast, or radiographs of the cervical spine may be appropriate for patients ≥16 yr with suspected acute blunt trauma of the cervical spine and as follow-up imaging for patients with no unstable injury demonstrated initially but kept in a collar for neck pain and no new neurologic symptoms, including whiplash-associated disorders.
• CT of the thoracic and lumbar spine without IV contrast is usually appropriate for the initial imaging of patients ≥16 yr with blunt trauma meeting criteria for thoracic and lumbar imaging. Thoracic and lumbar spine CT reconstructions can be performed from concurrently obtained CT imaging of the thorax or abdomen and pelvis in trauma patients who have been imaged for soft-tissue injuries, without the need for additional radiation exposure.
• MRI of the thoracic and lumbar spine without IV contrast is usually appropriate as the next imaging study for patients ≥16 yr with neurologic abnormalities and acute thoracic or lumbar spine injury detected on radiographs or noncontrast CT.

Administer steroids to any patient with blunt cervical spine injury and associated neurologic symptoms less than 8 hours in onset.

Class Summary

Agents have anti-inflammatory properties and cause profound, varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli.

Methylprednisolone (Solu-Medrol, Depo-Medrol, Medrol, A-Methapred)

Decrease inflammation by suppressing the migration of polymorphonuclear leukocytes and reversing increased capillary permeability.