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Cervical Spine

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Ovid: Handbook of Fractures

Authors: Koval, Kenneth J.; Zuckerman, Joseph D.
Title: Handbook of Fractures, 3rd Edition
> Table of Contents > II – Axial Skeleton Fractures > 9 – Cervical Spine

9
Cervical Spine
EPIDEMIOLOGY
  • Cervical spine injuries usually occur
    secondary to high-energy mechanisms, including motor vehicle accident
    (45%) and falls from a height (20%).
  • Less commonly, cervical spine injuries
    occur during athletic participation (15%), most notably during American
    football and diving events, and as a result of acts of violence (15%).
  • Neurologic injury occurs in 40% of patients with cervical spine fractures.
  • Spinal cord damage is more frequently associated with lower rather than upper cervical spine fractures and dislocations.
ANATOMY
  • The atlas is
    the first cervical vertebra, which has no body. Its two large lateral
    masses provide the only two weight-bearing articulations between the
    skull and the vertebral column.
    • The tectoral membrane and the alar ligaments are the key to providing normal craniocervical stability.
    • The anterior tubercle is held adjacent to the odontoid process of C2 by the transverse atlantal ligament.
    • Fifty percent of total neck flexion and extension occurs at the occiput-C1 junction.
    • The vertebral artery emerges from the
      foramen transversarium and passes between C1 and the occiput,
      traversing a depression on the superior aspect of the C1 ring.
      Fractures are common in this location.
  • The axis is the second cervical vertebra, whose body is the largest of the cervical vertebrae.
    • The transverse atlantal ligament (cruciform ligament) provides primary support for the atlantoaxial joint.
    • The alar ligaments are secondary stabilizers of the atlantoaxial joint.
    • The facet joint capsules at occiput-C1 and C1-C2 provide little support.
    • Fifty percent of total neck rotation occurs at the C1-C2 junction.
  • C3-C7 can be conceptualized as a three-column system (Denis) (Fig. 9.1):
    • Anterior column: The anterior vertebral
      body and intervertebral disc resist compressive loads, while the
      anterior longitudinal ligament and annulus fibrosis are the most
      important checkreins to distractive forces (extension).
    • Middle column: The posterior vertebral
      body and uncovertebral joints resist compression, while the posterior
      longitudinal ligament and annulus fibrosis limit distraction.
    • Posterior column: The facet joints and
      lateral masses resist compressive forces, while the facet joint
      capsules, interspinous ligaments, and supraspinous ligaments counteract
      distractive forces.

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    • The vertebral artery bypasses the empty
      foramen transversarium of C7 to enter the vertebral foramina of C6-C1.
      Injuries to the vertebral arteries are uncommon because of the
      redundancy of the vessel.
Figure
9.1. The components of the cervical three-column spine. The ligamentous
complexes resist distractive forces. The bony structures counteract
compression.

(From Rockwood CA Jr, Green DP, Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults, 4th ed, vol. 2. Philadelphia: Lippincott-Raven, 1996:1489.)
MECHANISM OF INJURY
  • Motor vehicle accidents (primarily in
    young patients), falls (primarily in older patients), diving accidents,
    and blunt trauma account for the majority of cervical spine injuries.
  • Forced flexion or extension resulting
    from unrestrained deceleration forces, with or without distraction or
    axial compression, is the mechanism for most cervical spine injuries.
Clinical Evaluation
  • Patient assessment is indicated: airway, breathing, circulation, disability, and exposure (ABCDE).
  • Initiate resuscitation: Address life-threatening injuries. Maintain rigid cervical immobilization.
  • Tracheal intubation and central line
    placement are often performed in the emergency setting. During
    intubation, manipulation of the neck can potentially displace unstable
    cervical fractures or dislocations. Manual in-line stabilization should
    be maintained throughout the intubation process. Alternatively, mask
    ventilation can be continued until fiberoptic or nasotracheal
    intubation can be safely performed. If an unstable spine is highly
    suspected, a cricothyroidotomy may be the safest alternative for airway
    control.
  • Evaluate the level of consciousness and neurologic impairment: Glasgow Coma Scale (see Chapter 2).
  • Assess head, neck, chest, abdominal, pelvic, extremity injury.
  • Ascertain the patient’s history:
    mechanism of injury, witnessed head trauma, movement of
    extremities/level of consciousness immediately following trauma, etc.
  • Physical examination
    • Neck pain
    • Lacerations and contusions on scalp, face, or neck
  • Neurologic examination

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    • Cranial nerves
    • Complete sensory and motor examination
    • Upper and lower extremity reflexes
    • Rectal examination: perianal sensation, rectal tone
    • Bulbocavernosus reflex (see Chapter 8)
Radiographic Evaluation
  • Lateral cervical spine radiograph: This
    will detect 85% of cervical spine injuries. One must visualize the
    atlantooccipital junction, all seven cervical vertebrae, and the
    cervicothoracic junction (as inferior as the superior aspect of T1).
    This may necessitate downward traction on both upper extremities or a
    swimmer’s view (upper extremity proximal to the x-ray beam abducted 180
    degrees, axial traction on the contralateral upper extremity, and the
    beam directed 60 degrees caudad). Patients complaining of neck pain
    should undergo complete radiographic evaluation of the cervical spine,
    including anteroposterior (AP) and odontoid views. On the lateral
    cervical spine radiograph, one may appreciate:
    • Acute kyphosis or loss of lordosis.
    • Continuity of radiographic “lines”:
      anterior vertebral line, posterior vertebral line, facet joint line, or
      spinous process line.
    • Widening or narrowing of disc spaces.
    • Increased distance between spinous processes or facet joints.
    • Abnormal retropharyngeal swelling, which depends on the level in question:
      • At C1: >10 mm
      • At C3, C4: >4 mm
      • At C5, C6, C7: >15 mm
    • Radiographic markers of cervical spine instability, including the following:
      • Compression fractures with >25% loss of height
      • Angular displacements >11 degrees between adjacent vertebrae (as measured by Cobb angle)
      • Translation >3.5 mm
      • Intervertebral disc space separation >1.7 mm (Figs. 9.2 and 9.3)
  • Computed tomography (CT) and/or magnetic
    resonance imaging (MRI) may be valuable to assess the upper cervical
    spine or the cervicothoracic junction, especially if it is inadequately
    visualized by plain radiography.
  • The proposed advantages of CT over a
    lateral cervical film as an initial screening tool are that it is more
    sensitive for detecting fractures and more consistently enables
    assessment of the occipitocervical and cervicothoracic junctions. A
    potential disadvantage of CT as an initial radiographic assessment is
    that subtle malalignment, facet joint gapping, or intervertebral
    distraction is difficult to assess using axial images alone.
  • The most useful applications of MRI are
    in detecting traumatic disc herniation, epidural hematoma, spinal cord
    edema or compression, and posterior ligamentous disruption. An
    additional application of MRI is the ability to visualize vascular
    structures.

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    MR arteriograms can be used to assess the patency of the vertebral arteries.
    Figure
    9.2. (A) Prevertebral soft tissue shadow. In a healthy recumbent adult
    without an endotracheal tube, the prevertebral soft tissue shadow
    should not exceed 6 mm. (B) Bony screening lines and dens angulation.
    The anterior cortex of the odontoid should parallel the posterior
    cortex of the anterior ring of the atlas. Any kyphotic or lordotic
    deviation should be viewed with suspicion for an odontoid fracture or
    transverse atlantal ligament disruption. Wackenheim line is drawn as a
    continuation from the clivus caudally. The tip of the odontoid should
    be within 1 to 2 mm of this line. The C1-C3 spinolaminar line’s
    reference points are drawn from the anterior cortex of the laminae of
    the atlas, axis, and C3 segments, which should fall within 2 mm of one
    another. Greater deviation should raise suspicion of atlantoaxial
    translation or disruption of the neural arches of either segment. (C)
    Ligamentous injury reference lines (lateral x-rays). The atlas-dens
    interval (ADI) should be less than 3 mm in an adult (5 mm in a child).
    The space available for the cord is measured as the distance from the
    posterior cortex of the odontoid tip to the anterior cortex of the
    posterior arch of the atlas and should amount to more than 13 mm. The
    dens-basion interval (DBI) is the distance between the odontoid tip and
    the distal end of the basion. It should be less than 12 mm in adults.
    The posterior axis line (PAL-B) should not be more than 4 mm anterior
    and should be less than 12 mm posterior to the basion. (D) Bony
    screening lines (anteroposterior imaging). The left and right lateral
    atlas-dens intervals (LADIs) should be symmetric to one another (with
    2-mm deviation). The bony components of the atlantooccipital joints
    should be symmetric and should not be spaced more than 2 mm apart on
    anteroposterior images. (Courtesy of Fred Mann, MD, Professor of
    Radiology, University of Washington, Seattle.)
    Figure
    9.3. Radiographic indications of instability. Greater than 3.5 mm of
    translation (A) or 11 degrees of angulation (B) and widening of the
    separation between spinous processes are indications of instability on
    the lateral plain film.

    (Adapted from Bucholz RW. Lower cervical spine injuries. In: Browner BD, Jupiter JB, Levine AM, et al. eds. Skeletal Trauma, vol. 1. Philadelphia: WB Saunders, 1992:707.)

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  • Stress flexion/extension radiographs
    rarely if ever should be performed if instability is suspected; they
    should be performed in the awake and alert patient only. In a patient
    with neck pain, they are best delayed until spasm has subsided, which
    can mask instability. The atlantodens interval (ADI) should be <3 mm
    in adults and <5 mm in children.
  • Traction x-rays are taken during reductions only.
CLASSIFICATION
OTA Classification of Cervical Spine Injuries
See Fracture and Dislocation Compendium at http://www.ota.org/compendium/index.htm.
INJURIES TO THE OCCIPUT-C1-C2 COMPLEX
  • As with other transitional regions of the
    spine, the craniocervical junction is highly susceptible to injury.
    This region’s vulnerability to injury is particularly high because of
    the large lever-arm induced cranially by the skull and the relative
    freedom of movement of the craniocervical junction, which relies
    disproportionately on ligamentous structures rather than on intrinsic
    bony stability.
Occipital Condyle Fractures
  • These are frequently associated with C1 fractures as well as cranial nerve palsies.
  • The mechanism of injury involves
    compression and lateral bending; this causes either compression
    fracture of the condyle as it presses against the superior facet of C1
    or avulsion of the alar ligament with extremes of atlantooccipital
    rotation.
  • CT is frequently necessary for diagnosis.

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CLASSIFICATION (FIG. 9.4)
Figure
9.4. Anderson and Montesano classification of occipital condyle
fractures. (A) Type I injuries are comminuted, usually stable,
impaction fractures caused by axial loading. (B) Type II injuries are
impaction or shear fractures extending into the base of the skull, and
are usually stable. (C) Type III injuries are alar ligament avulsion
fractures and are likely to be unstable distraction injuries of the
craniocervical junction.

(From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)

Type I: Impaction of condyle; usually stable
Type II: Shear injury associated with basilar or skull fractures; potentially unstable
Type III: Condylar avulsion; unstable
  • Treatment includes rigid cervical collar
    immobilization for 8 weeks for stable injuries and halo immobilization
    or occipital-cervical fusion for unstable injuries.

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  • Craniocervical dissociation should be considered with any occipital condyle fracture.
    Figure 9.5. Powers ratio.

    (From Browner BD, Jupiter JB, Levine AM, et al. eds. Skeletal Trauma, vol. 1. Philadelphia: WB Saunders, 1992:668.)
Occipitoatlantal Dislocation (Craniovertebral Dissociation)
  • This is almost always fatal, with
    postmortem studies showing it to be the leading cause of death in motor
    vehicle accidents; rare survivors have severe neurologic deficits
    ranging from complete C1 flaccid quadriplegia to mixed incomplete
    syndromes such as Brown-Séquard.
  • This is twice as common in children, owing to the inclination of the condyles.
  • It is associated with submental lacerations, mandibular fractures, and posterior pharyngeal wall lacerations.
  • It is associated with injury to the
    cranial nerves (the abducens and hypoglossal nerves are most commonly
    affected by craniocervical injuries), the first three cervical nerves,
    and the vertebral arteries.
  • The cervicomedullary syndromes, which
    include cruciate paralysis as described by Bell and hemiplegia cruciata
    initially described by Wallenberg, represent the more unusual forms of
    incomplete spinal cord injury and are a result of the specific anatomy
    of the spinal tracts at the junction of the brainstem and spinal cord.
    Cruciate paralysis can be similar to a central cord syndrome, although
    it normally affects proximal more than distal upper extremity function.
    Hemiplegia cruciata is associated with ipsilateral arm and
    contralateral leg weakness.
  • Mechanism is a high-energy injury
    resulting from a combination of hyperextension, distraction, and
    rotation at the craniocervical junction.
  • The diagnosis is often missed, but it may be made on the basis of the lateral cervical spine radiograph:
    • The tip of odontoid should be in line with the basion.
    • The odontoid-basion distance is 4 to 5 mm in adults and up to l0 mm in children.
    • Translation of the odontoid on the basion is never greater than 1 mm in flexion/extension views.
    • Powers ratio (BC/OA) should be <1 (Fig. 9.5).

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    • In adults, widening of the prevertebral
      soft tissue mass in the upper neck is an important warning sign of
      significant underlying trauma and may be the only sign of this injury.
    • Fine-cut CT scans with slices no more
      than 2 mm wide are helpful to understand articular incongruities or
      complex fracture patterns more clearly. MRI of the craniovertebral
      junction is indicated for patients with spinal cord injury and can be
      helpful to assess upper cervical spine ligamentous injuries as well as
      subarachnoid and prevertebral hemorrhage.
  • Classification based on the position of the occiput in relation to C1 is as follows:

    Type I: Occipital condyles anterior to the atlas; most common
    Type II: Condyles longitudinally dissociated from atlas without translation; result of pure distraction
    Type III: Occipital condyles posterior to the atlas
  • The Harborview classification attempts to
    quantify stability of craniocervical junction. Surgical stabilization
    is reserved for type II and III injuries.

    Type I: Stable with displacement <2 mm
    Type II: Unstable with displacement <2 mm
    Type III: Gross instability with displacement >2 mm
  • Immediate treatment includes halo vest
    application with strict avoidance of traction. Reduction maneuvers are
    controversial and should ideally be undertaken with fluoroscopic
    visualization.
  • Long-term stabilization involves fusion between the occiput and the upper cervical spine.
Atlas Fractures
  • These are rarely associated with neurologic injury.
  • Instability invariably equates to the
    presence of transverse alar ligament insufficiency, which can be
    diagnosed either by direct means, such as by identifying bony avulsion
    on CT scan or ligament rupture on MRI, or indirectly by identifying
    widening of the lateral masses.
  • Fifty percent of these injuries are
    associated with other cervical spine fractures, especially odontoid
    fractures and spondylolisthesis of the axis.
  • Cranial nerve lesions of VI to XII and neurapraxia of the suboccipital and greater occipital nerves may be associated.
  • Vertebral artery injuries may cause symptoms of basilar insufficiency such as vertigo, blurred vision, and nystagmus.
  • Patients may present with neck pain and a subjective feeling of “instability.”
  • The mechanism of injury is axial
    compression with elements of hyperextension and asymmetric loading of
    condyles causing variable fracture patterns.
  • Classification (Levine) (Fig. 9.6)
    • Isolated bony apophysis fracture
    • Isolated posterior arch fracture
    • Isolated anterior arch fracture
    • Comminuted lateral mass fracture
    • Burst fracture

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  • Treatment
    Figure
    9.6. Classification of atlas fractures (according to Levine). (A)
    Isolated bony apophysis fracture. (B) Isolated posterior arch fracture.
    (C) Isolated anterior arch fracture. Comminuted lateral mass fracture
    (D) and burst fracture (E), three or more fragments.

    (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)
    • Initial treatment includes halo traction/immobilization.
    • Stable fractures (posterior arch or
      nondisplaced fractures involving the anterior and posterior portions of
      the ring) may be treated with a rigid cervical orthosis.
    • Less stable configurations (asymmetric
      lateral mass fracture with “floating” lateral mass, burst fractures)
      may require prolonged halo immobilization.
    • C1-C2 fusion may be necessary to alleviate chronic instability and/or pain.
Transverse Ligament Rupture (Traumatic C1-C2 Instability)
  • This rare, usually fatal injury, is seen mostly in older age groups (50s to 60s).
  • The mechanism of injury is forced flexion.

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  • The clinical picture ranges from severe neck pain to complete neurologic compromise.
    Figure 9.7. Axial CT image demonstrating transverse ligament rupture with atlanto-axial subluxation

    (Reproduced with permission from Bucholz RW, Heckman JD, Court-Brown C, et al. eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams Wilkins, 2006.)
  • Rupture of the transverse ligament may be determined by:
    • Visualizing the avulsed lateral mass fragment on CT scan.
    • Atlantoaxial offset >6.9 mm on an odontoid radiograph.
    • ADI >3 mm in adults. An ADI >5 mm in adults also implies rupture of the alar ligaments.
    • Direct visualization of the rupture on MRI.
  • Treatment
    • Initial treatment includes halo traction/immobilization.
    • In the cases of avulsion, halo immobilization is continued until osseous healing is documented.
    • C1-C2 fusion is indicated for tears of the transverse ligament without bony avulsion, chronic instability, or pain (Fig. 9.7)
Atlantoaxial Rotary Subluxation and Dislocation
  • In this rare injury, patients present
    with confusing complaints of neck pain, occipital neuralgia, and,
    occasionally, symptoms of vertebrobasilar insufficiency. In chronic
    cases, the patient may present with torticollis.
  • It is infrequently associated with neurologic injury.
  • The mechanism of injury is
    flexion/extension with a rotational component, although in some cases
    it can occur spontaneously with no reported history of trauma.
  • Odontoid radiographs may show asymmetry
    of C1 lateral masses with unilateral facet joint narrowing or overlap
    (wink sign). The C2 spinous process may be rotated from the midline on
    an AP view.
  • The subluxation may be documented on
    dynamic CT scans; failure of C1 to reposition on a dynamic CT scan
    indicates fixed deformity.

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  • Classification (Fielding)

    Type I: Odontoid as a pivot point; no neurologic injury; ADI <3 mm; transverse ligament intact (47%)
    Type II: Opposite facet as a pivot; ADI <5 mm; transverse ligament insufficient (30%)
    Type III: Both joints anteriorly subluxed; ADI >5 mm; transverse and alar ligaments incompetent
    Type IV: Rare; both joints posteriorly subluxed
    Type V: Levine and Edwards: frank dislocation; extremely rare
  • Treatment
    • Cervical halter traction in the supine
      position and active range-of-motion exercises for 24 to 48 hours
      initially are followed by ambulatory orthotic immobilization with
      active range-of-motion exercises until free motion returns.
    • Rarely, fixed rotation with continued symptoms and lack of motion indicates a C1-C2 posterior fusion
Fractures of the Odontoid Process (Dens)
  • A high association exists with other cervical spine fractures.
  • There is a 5% to10% incidence of
    neurologic involvement with presentation ranging from Brown-Séquard
    syndrome to hemiparesis, cruciate paralysis, and quadriparesis.
  • Vascular supply arrives through the apex of the odontoid and through its base with a watershed area in the neck of the odontoid.
  • High-energy mechanisms of injury include
    motor vehicle accident or falls with avulsion of the apex of the dens
    by the alar ligament or lateral/oblique forces that cause fracture
    through the body and base of the dens.
  • Classification: (Anderson and D’Alonzo) (Fig. 9.8).

    Type I: Oblique avulsion fracture of the apex (5%)
    Type II: Fracture at the junction of the body and the neck; high nonunion rate, which can lead to myelopathy (60%)
    Type IIA: Highly unstable comminuted injury extending from the waist of the odontoid into the body of the axis
    Type III: Fracture extending into the cancellous body of C2 and possibly involving the lateral facets (30%)
  • Treatment

    Type I: If it is an isolated injury, stability of the fracture pattern allows for immobilization in a cervical orthosis.
    Type II: This is controversial, because
    the lack of periosteum and cancellous bone and the presence in
    watershed area result in a high incidence of nonunion (36%). Risk
    factors include age >50 years, >5 mm displacement, and posterior
    displacement. It may require screw fixation of the odontoid or C1-C2
    posterior fusion for adequate treatment. Nonoperative treatment is halo
    immobilization.
    Type III: There is a high likelihood of union with halo immobilization owing to the cancellous bed of the fracture site.

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C2 Lateral Mass Fractures
Figure
9.8. The odontoid fracture classification of Anderson and D’Alonzo. (A)
Type I fractures of the odontoid tip represent alar ligament avulsions.
(B) Type II fractures occur at the odontoid waist, above the C2 lateral
masses. (C) Type III fractures extend below the odontoid waist to
involve the body and lateral masses of C2. Hadley has added the type
IIA fracture with segmental comminution at the base of the odontoid
(not shown)

(From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)
  • Patients often present with neck pain, limited range of motion, and no neurologic injury.
  • The mechanisms of injury are axial compression and lateral bending.
  • CT is helpful for diagnosis.
  • A depression fracture of the C2 articular surface is common.
  • Treatment ranges from collar immobilization to late fusion for chronic pain.
Traumatic Spondylolisthesis of C2 (Hangman’s Fracture)
  • This is associated with a 30% incidence
    of concomitant cervical spine fractures. It may be associated with
    cranial nerve, vertebral artery, and craniofacial injuries.
  • The incidence of spinal cord injury is low with types I and II and high with type III injuries.
  • The mechanism of injury includes motor
    vehicle accidents and falls with flexion, extension, and axial loads.
    This may be associated with varying degrees of intervertebral disc
    disruption. Hanging mechanisms involve hyperextension and distraction

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    injury,
    in which the patient may experience bilateral pedicle fractures and
    complete disruption of disc and ligaments between C2 and C3.

    Figure
    9.9. Classification of traumatic spondylolisthesis of the axis
    (hangman’s fracture) (according to Effendi, modified by Levine). (A)
    Type I, nondisplaced fracture of the pars interarticularis. (B) Type
    II, displaced fracture of the pars interarticularis. (C) Type IIa,
    displaced fracture of the pars interarticularis with disruption of the
    C2-C3 discoligamentous complex. (D) Type III, dislocation of C2-C3
    facets joints with fractured pars interarticularis

    (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)
  • Classification (Levine and Edwards; Effendi) (Fig. 9.9)

    Type I: Nondisplaced, no angulation; translation <3 mm; C2-C3 disc intact (29%); relatively stable
    Type Ia: Atypical unstable lateral
    bending fractures that are obliquely displaced and usually involve only
    one pars interarticularis, extending anterior to the pars and into the
    body on the contralateral side
    Type II: Significant angulation at
    C2-C3; translation >3 mm; most common injury pattern; unstable;
    C2-C3 disc disrupted (56%); subclassified into flexion, extension, and
    listhetic types
    Type IIA: Avulsion of entire C2-C3
    intervertebral disc in flexion with injury to posterior longitudinal
    ligament, leaving the anterior longitudinal ligament intact; results in
    severe angulation; no translation; unstable; probably caused by
    flexion-distraction injury (6%); traction contraindicated
    Type III: Rare; results from initial
    anterior facet dislocation of C2 on C3 followed by extension injury
    fracturing the neural arch; results in severe angulation and
    translation with unilateral or bilateral facet dislocation of C2-C3;
    unstable (9%); type III injuries most commonly associated with spinal
    cord injury

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  • Treatment

    Type I: This usually requires rigid cervical orthosis for up to 6 weeks.
    Type II: This is determined by
    stability; it usually requires halo traction/immobilization with serial
    radiographic confirmation of reduction for at least 6 weeks.
    Type IIA: Traction may exacerbate the condition; therefore, only immobilization may be indicated.
    Type III: Initial halo traction is followed by open reduction and posterior fusion of C2-C3, with possible anterior fusion.
INJURIES TO C3-C7
  • Vertebral bodies have a superior cortical
    surface that is concave in the coronal plane and convex in the sagittal
    plane, allowing for flexion, extension, and lateral tilt by the gliding
    motion of the facets.
  • The uncinate process projects superiorly
    from the lateral aspect of the vertebral body. With degenerative
    changes, these may articulate with the superior vertebra, resulting in
    an uncovertebral joint (of Luschka).
  • The mechanism of injury includes motor vehicle accidents, falls, diving accidents, and blunt trauma.
  • Radiographic evaluation consists of AP,
    lateral, and odontoid views of the cervical spine, as described earlier
    in the section on radiographic evaluation of cervical spine
    instability).
    • If cervical spine instability is
      suspected, flexion/extension views may be obtained in a willing,
      conscious, and cooperative patient without neurologic compromise. A
      “stretch” test (Panjabi and White) may be performed with longitudinal
      cervical traction. An abnormal test is indicated by a greater than
      1.7-mm interspace separation or a >7.5-degree change between
      vertebrae.
    • CT scans with reconstructions may be obtained to characterize fracture pattern and degree of canal compromise more clearly.
    • MRI may be undertaken to delineate spinal cord, disc, and canal abnormalities further.
    • The amount of normal cervical motion at
      each level has been extensively described, and this knowledge can be
      important in assessing spinal stability after treatment.
      Flexion-extension motion is greatest at the C4-5 and C5-6 segments,
      averaging about 20 degrees. Axial rotation ranges from 2 to 7 degrees
      at each of the subaxial motion segments; the majority (45% to 50%) of
      rotation occurs at the C1-C2 articulation. Lateral flexion is 10 to 11
      degrees per level in the upper segments (C2-5). Lateral motion
      decreases caudally, with only 2 degrees observed at the cervicothoracic
      junction.

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Classification (Allen-Ferguson) (Fig. 9.10)
Figure 9.10. (A–E) The five stages of compression flexion injuries.

(From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)
  • Compressive flexion (shear mechanism resulting in “teardrop” fractures)

    Stage I: Blunting of anterior body; posterior elements intact
    Stage II: “Beaking” of the anterior body; loss of anterior vertebral height
    Stage III: Fracture line passing from anterior body through the inferior subchondral plate
    Stage IV: Inferoposterior margin displaced <3 mm into the neural canal
    Stage V: “Teardrop” fracture;
    inferoposterior margin >3 mm into the neural canal; failure of the
    posterior ligaments and the posterior longitudinal ligament
  • Vertical compression (burst fractures) (Fig. 9.11)

    Stage I: Fracture through the superior or inferior endplate with no displacement
    Stage II: Fracture through both endplates with minimal displacement
    Stage III: Burst fracture; displacement of fragments peripherally and into the neural canal
  • Distractive flexion (dislocations) (Fig. 9.12)

    Stage I: Failure of the posterior ligaments, divergence of the spinous processes, and facet subluxation
    Stage II: Unilateral facet dislocation; translation always <50%
    Stage III: Bilateral facet dislocation; translation of 50% and “perched” facets
    Stage IV: Bilateral facet dislocation with 100% translation

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  • Compressive extension (Fig. 9.13)
    Figure 9.11. (A–C) The three stages of vertical compression injuries.

    (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)

    Stage I: Unilateral vertebral arch fracture
    Stage II: Bilateral laminar fracture without other tissue failure
    Stages III, IV: Theoretic continuum between stages II and V
    Stage V: Bilateral vertebral arch
    fracture with full vertebral body displacement anteriorly; ligamentous
    failure at the posterosuperior and anteroinferior margins
    Figure 9.12. (A–D) The four stages of distraction flexion injuries.

    (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)

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  • Distractive extension (Fig. 9.14)
    Figure 9.13. (A–E) The five stages of compression extension injuries.

    (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)

    Stage I: Failure of anterior
    ligamentous complex or transverse fracture of the body; widening of the
    disc space and no posterior displacement
    Stage II: Failure of posterior ligament complex and superior displacement of the body into the canal
    Figure 9.14. (A and B) The two stages of distraction extension injuries.

    (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.)
  • Lateral flexion (Fig. 9.15)

    Stage I: Asymmetric, unilateral
    compression fracture of the vertebral body plus a vertebral arch
    fracture on the ipsilateral side without displacement
    Stage II: Displacement of the arch on the AP view or failure of the ligaments on the contralateral side with articular process separation

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  • Miscellaneous cervical spine fractures
    Figure
    9.15. Lateral flexion injuries. Blunt trauma from the side places the
    ipsilateral spine in distraction while compressing the contralateral
    spine. (A) Stage I injury, asymmetric centrum fracture with a
    unilateral arch fracture. (B) Stage II injury, with displacement of the
    body and contralateral ligamentous failure.

    (Adapted from Rizzolo SJ, Cotler JM. Unstable cervical spine injuries: specific treatment approaches. J Am Acad Orthop Surg 1993;1:57–66.)
    • “Clay shoveler’s” fracture: This is an
      avulsion of the spinous processes of the lower cervical and upper
      thoracic vertebrae. Historically, this resulted from muscular avulsion
      during shoveling in unyielding clay with force transmission through the
      contracted shoulder girdle. Treatment includes restricted motion and
      symptomatic treatment until clinical improvement or radiographic
      healing of the spinous process occurs.
    • Sentinel fracture: This fracture occurs
      through the lamina on either side of the spinous process. A loose
      posterior element may impinge on the cord. Symptomatic treatment only
      is indicated unless spinal cord compromise exists.
    • Ankylosing spondylitis: This may result
      in calcification and ossification of the ligamentous structures of the
      spine, producing “chalk stick” fractures after trivial injuries. These
      fractures are notoriously unstable because they tend to occur through
      brittle ligamentous structures. Treatment includes traction with
      minimal weight in flexion, with aggressive immobilization with either
      halo vest or open stabilization.
    • Gunshot injuries: Missile impact against
      bony elements may cause high-velocity fragmentation frequently
      associated with gross instability and complete spinal cord injury.
      Surgical extraction of missile fragments is rarely indicated in the
      absence of canal compromise. Missiles that traverse the esophagus or
      pharynx should be removed, with

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      aggressive
      exposure and debridement of the missile tract. These injuries carry
      high incidences of abscess formation, osteomyelitis, and mediastinitis.

TREATMENT: GENERAL CERVICAL SPINE
Initial Treatment
  • Immobilization with a cervical orthosis
    (for stable fractures) or Gardner-Wells tong traction (for unstable
    injuries) should be maintained in the emergency setting before CT for
    evaluation of spinal and other system injuries.
  • Vasopressor support is indicated for suspected neurogenic shock and emergency assessment for potential intracranial trauma.
  • Patients with neurologic injuries should
    be considered for intravenous methylprednisolone per the NASCIS II and
    III protocol (30 mg/kg loading dose and then 5.4 mg/kg for 24 hours if
    started within 3 hours, for 48 hours if started within 8 hours.
    Steroids have no benefit if they are started more than 8 hours after
    injury).
  • The majority of cervical spine fractures
    can be treated nonoperatively. The most common method of nonoperative
    treatment is immobilization in a cervical orthosis. In reality,
    orthoses decrease motion rather than effect true immobilization. Motion
    at the occipital-cervical junction is slightly increased by most
    cervical collars.
    • Soft cervical orthosis: This produces no significant immobilization and is a supportive treatment for minor injuries.
    • Rigid cervical orthosis (Philadelphia
      collar): This is effective in controlling flexion and extension;
      however, it provides little rotational or lateral bending stability.
    • Poster braces: These are effective in controlling midcervical flexion, with fair control in other planes of motion.
    • Cervicothoracic orthoses: These are
      effective in flexion and extension and rotational control, with limited
      control of lateral bending.
    • Halo device: This provides the most rigid immobilization (of external devices) in all planes.
    • For traction, Gardner-Wells tongs are
      applied one finger’s width above the pinna of the ear in line with the
      external auditory canal. Slight anterior displacement will apply an
      extension force, whereas posterior displacement will apply a flexion
      force, useful when reducing facet dislocations (Fig. 9.16).
    • Numerous complications are associated
      with use of cervical collars. Skin breakdown at bony prominences, in
      particular the occiput, mandible, and sternum can occur. Up to 38
      percent of patients with severe closed head injuries can develop skin
      complications with prolonged use.
  • Patients with neural deficits from
    burst-type injuries: Traction is used to stabilize and indirectly
    decompress the canal via ligamentotaxis.
  • Patients with unilateral or bilateral
    facet dislocations and complete neural deficits: Gardner-Wells tong
    traction and reduction by sequentially increasing the amount of
    traction are indicated.
  • Traction is contraindicated in distractive cervical spine injuries and type IIA spondylolisthesis injuries of C2.

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  • Patients with incomplete neural deficits
    or who are neurologically intact with unilateral and bilateral facet
    dislocations require MRI before reduction via traction to evaluate for
    a herniated disc, especially if a patient is not awake and alert and
    able to cooperate with serial examinations during reduction maneuvers.
    Figure
    9.16. Closed reduction technique. Diagram of cranial tong technique for
    maintaining alignment and stability of the spine. Weight is increased
    gradually with a maximum of 45 to 50 lb (10 lb for the head and 5 lb
    for each successive interspace). Patients with an unrevealing
    examination may require a magnetic resonance imaging scan before
    reduction to rule out a space-occupying lesion in the vertebral canal.
    Failure of reduction may also necessitate such a scan.

    (Adapted from Bucholz RW. Lower cervical spine injuries. In: Browner BD, Jupiter JB, Levine AM, et al., eds. Skeletal Trauma, vol. 1. Philadelphia: WB Saunders, 1992:638.)
  • A halo has been recommended for patients
    with isolated occipital condyle fractures, unstable atlas ring
    fractures, odontoid fractures, and displaced neural arch fractures of
    the axis.
  • The halo vest relies on a tight fit of
    the vest around the torso and is poorly tolerated by elderly patients
    and patients with pulmonary compromise or thoracic deformities, such as
    those with ankylosing spondylitis.
  • The halo ring should be applied 1 cm
    above the ears. Anterior pin sites should be placed below the equator
    of the skull above the supraorbital ridge, anterior to the temporalis
    muscle, and over the lateral two-thirds of the orbit. Posterior sites
    are variable and are placed to maintain horizontal orientation of the
    halo. Pin pressure should be 6 to 8 lb in the adult and should be
    tightened at 48 hours and monthly thereafter. Pin care is essential.
  • Prolonged recumbence carries an increased
    morbidity and mortality risk, and consideration should be given to the
    use of a RotoRest bed and mechanical as well as pharmacologic
    thromboprophylaxis.
  • Because of the normally wide spinal canal
    diameter, decompression of neural elements in upper cervical spine
    fractures is not commonly required for traumatic conditions.

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  • The optimal time to perform surgery,
    particularly in patients with neurologic deficits, remains unclear. The
    two most commonly proposed benefits of earlier versus later surgery are
    improved rates of neurologic recovery and improved ability to mobilize
    the patient without concern of spinal displacement. To date, little
    human clinical evidence supports the view that early surgical
    decompression and stabilization improve neurologic recovery rates.
    However, clinical series have demonstrated that surgery performed as
    soon as 8 hours after injury does not appear to increase the rate of
    complications or lead to neurologic decline.
Stabilization of the Upper Cervical Spine (Occiput-C2)
  • The mainstay of operative treatment of
    upper cervical fractures and dislocations remains fusion with
    instrumentation, most commonly performed from the posterior approach.
    In order of frequency, the most common upper cervical fusion procedures
    are atlantoaxial fusion, occipitocervical fusion, and least commonly,
    C1-C3 fusion.
  • Fusion of the occiput-C1 limits 50% of flexion and extension.
  • Fusion of C1-C2 limits 50% of rotation.
Anterior Approach
There are three main indications for anterior upper cervical spine exposure in trauma.
  • Screw fixation of a type II odontoid fracture
  • Anterior interbody fusion and plating of the C2-3 interspace for a type IIA or III hangman’s fracture
  • Anterior arthrodesis of the atlantoaxial
    articulations as a rare salvage procedure for failed posterior
    atlantoaxial fusion at-tempts
Posterior Approach
Most upper cervical fractures are treated through a posterior approach.
  • Modified Brooks or Gallie arthrodesis uses sublaminar wires and a bone graft between the arches of C1 and C2.
    • Flexion control is obtained via the
      wires, extension via the bone blocks, and rotation via friction between
      the bone blocks and the posterior arches.
  • Transarticular screws are effective, especially if the posterior elements of C1 and C2 are fractured.
Osteosynthesis
  • The two indications for direct fracture
    repair in the upper cervical spine involve the treatment of type II
    odontoid fractures or type II traumatic spondylolistheses of C2 with
    interfragmentary screw fixation.
  • This is not indicated for fixation of anteriorly displaced odontoid fractures.
Stabilization of the Lower Cervical Spine (C3-C7)
  • Fifty percent of flexion/extension and 50% of rotation are evenly divided between each of the facet articulations.

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  • Fusion of each level reduces motion by a proportionate amount.
  • Posterior decompression and fusion:
    • The posterior approach to the cervical
      spine is a midline, extensile approach that can be used to access as
      many spinal levels as necessary, with a variety of instrumentation
      techniques in use.
    • In the majority of acute, traumatic,
      subaxial spinal injuries, posterior decompression via laminectomy is
      not necessary. Canal compromise is most frequently caused by
      dislocation, translation, or retropulsed vertebral body fragments. In
      rare cases of anteriorly displaced posterior arch fragments,
      laminectomy would be indicated to directly remove the offending
      compressive elements. This is not true, however, in cases of acute
      spinal cord injury associated with multilevel spondylotic stenosis or
      ossification of the posterior longitudinal ligament, in which a
      posterior decompressive procedure may be considered the procedure of
      choice if cervical lordosis has been maintained.
    • Open reduction of dislocated facet joints is typically performed using a posterior approach.
  • Bilateral lateral mass plating
    • This can be utilized for a variety of
      fractures including facet fractures, facet dislocations, and “teardrop”
      (compressive flexion stage V) fractures.
    • Single-level fusions are sufficient for dislocations, although multilevel fusions may be required for more unstable patterns.
    • This can stop fusion at levels with
      fractured spinous processes or laminae, thus avoiding the fusion of
      extra levels with consequent loss of motion.
  • Anterior decompression and fusion
    • These are used for vertebral body burst fractures with spinal cord injury and persistent anterior cord compression.
    • The anterior approach to the subaxial
      spine utilizes the interval plane between the sternocleidomastoid
      (lateral) and anterior strap (medial) muscles. Deeper, the interval of
      dissection is between the carotid sheath laterally and the
      trachea/esophagus medially.
    • MRI, myelography, and CT are valuable in preoperative assessment of bony and soft tissue impingement on the spinal cord.
    • A simple discectomy or corpectomy in
      which osseous fragments are removed from the canal and a tricortical
      iliac or fibular graft placed between the vertebral bodies by a variety
      of techniques can be performed.
    • In the presence of a herniated cervical
      disc associated with dislocated facet joints, one may elect to perform
      an anterior discectomy and decompression before facet reduction.
    • Anterior plating or halo vest immobilization adds stability during healing.
COMPLICATIONS
Complications of spinal cord injury are covered in Chapter 8.

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