Cervical Spine Fracture Evaluation

Updated: Nov 01, 2022
  • Author: Moira Davenport, MD; Chief Editor: Trevor John Mills, MD, MPH  more...
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Overview

Practice Essentials

Cervical spine injuries occur in 3-4% and thoracolumbar fractures in 4-7% of blunt trauma patients who present to the emergency department. [1] Approximately 5-10% of unconscious patients who present to the emergency department (ED) as the result of a motor vehicle accident or a fall have a major injury to the cervical spine. Most cervical spine fractures occur predominantly at 2 levels: one third of injuries occur at the level of C2, and one half of injuries occur at the level of C6 or C7. Most fatal cervical spine injuries occur at upper cervical levels, at craniocervical junction C1 or C2. [2, 3, 4, 5, 6, 7, 8, 9]

Anatomy

The normal anatomy of the cervical spine consists of 7 cervical vertebrae separated by intervertebral disks and joined by a complex network of ligaments. These ligaments keep individual bony elements behaving as a single unit. [8]

The cervical spine is viewed as 3 distinct columns: anterior, middle, and posterior. The anterior column is composed of the anterior longitudinal ligament and the anterior two thirds of the vertebral bodies, the annulus fibrosus, and the intervertebral disks. The middle column is composed of the posterior longitudinal ligament and the posterior one third of the vertebral bodies, the annulus, and intervertebral disks. The posterior column contains all of the bony elements formed by the pedicles, transverse processes, articulating facets, laminae, and spinous processes.

The anterior and posterior longitudinal ligaments maintain the structural integrity of the anterior and middle columns. The posterior column is held in alignment by a complex ligamentous system, including the nuchal ligament complex, the capsular ligaments, and the ligamenta flava.

If one column is disrupted, other columns may provide sufficient stability to prevent spinal cord injury. If 2 columns are disrupted, the spine may move as 2 separate units, increasing the likelihood of spinal cord injury.

The atlas (C1) and the axis (C2) differ markedly from other cervical vertebrae. The atlas has no vertebral body; however, it is composed of a thick anterior arch with 2 prominent lateral masses and a thin posterior arch. The axis contains the odontoid process that represents fused remnants of the atlas body. The odontoid process is held in tight approximation to the posterior aspect of the anterior arch of C1 by the transverse ligament, which stabilizes the atlantoaxial joint. [8, 10]

Apical, alar, and transverse ligaments provide further stabilization by allowing spinal column rotation; this prevents posterior displacement of the dens in relation to the atlas.

In pediatric patients, the spine is more flexible, and therefore, neural damage occurs much earlier than musculoskeletal injury in young patients. Because of this high flexibility, fatal consequences can occur with sometimes even minimal structural damage. Compared to adults, children have a different fulcrum because of a relatively large head, the vertebrae are not completely ossified, and the ligaments are firmly attached to articular bone surfaces that are more horizontal, making the pathophysiology of injury in children different from that in adults. [7, 11]

Evaluation of injury

When a cervical spine injury is suspected, neck movement should be minimized during transport to the treating facility. Ideally, patients should be transported on a backboard with a semirigid collar, with the neck stabilized on the sides of the head with sandbags or foam blocks taped from side to side (of the board), across the forehead.

If spinal malalignment is identified, place the patient in skeletal traction with tongs as soon as possible (with very few exceptions), even if no evidence of neurologic deficit exists. The specific injury involved and the capabilities of the consulting staff guide further management.

Place tongs 1 fingerwidth above the ear lobes in alignment with the external auditory canal. The consultant applies the tongs for traction under close neurologic and radiographic surveillance. Care must be taken while managing the airway in patients with potential cervical spine injuries. Video-assisted intubation should be considered to limit cervical spine motion during the process of securing the airway. [2, 12, 13, 14]

Cervical spine injuries are best classified according to several mechanisms of injury. These include flexion, flexion-rotation, extension, extension-rotation, vertical compression, lateral flexion, and imprecisely understood mechanisms that may result in odontoid fractures and atlanto-occipital dislocation. Cervical spine injuries cause an estimated 6000 deaths and 5000 new cases of quadriplegia each year. Male-to-female ratio is 4:1. Most patients with a cervical spine injury are in their prime and are leading an active lifestyle prior to injury. Approximately 80% of patients are aged 18-25 years. [2, 5, 6, 8, 15, 16, 17]

Radiographic evaluation is indicated in the following [3, 16, 18, 19, 20, 21] :

  • 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

A standard trauma series is composed of 5 views: cross-table lateral, swimmer's, oblique, odontoid, and anteroposterior. Approximately 85-90% of cervical spine injuries are evident in lateral view, making it the most useful view from a clinical standpoint.

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]

Injuries commonly associated with multiple or complex mechanisms include odontoid fracture, fracture of the transverse process of C2 (lateral flexion), atlanto-occipital dislocation (flexion or extension with a shearing component), and occipital condyle fracture (vertical compression with lateral bending).

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Flexion Injury

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 (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 (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 s 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 mechani 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 f 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]

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Flexion-Rotation Injury

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 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 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.

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Extension Injury

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 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 (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]

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Vertical (Axial) Compression Injury

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 (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 verti 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]

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Mechanism of Injury, Location, and Clinical Relevance

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 r 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.

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Mechanical Instability

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)

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