Cervical Spine Injuries (Acute)

Canadian cervical spine imaging decision rules.

Anatomy

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Flexion Injuries

C1/C2

• Atlanto-occipital dislocation , atlantoaxial dislocations , potentially associated with odontoid fracture.
• Imaging: Basion-dens interval (BDI) >10mm,
• Stability: Unstable.

Wedge fracture

• Stretch on strong nuchal ligament transmits force to vertebral body.
• Stability: Generally stable unless >50% compression or multiple contiguous.

Flexion-teardrop fracture

• Severe flexion force, avulsion of fragment of anterior/inferior portion of vertebral body.
• Stability: Unstable, involves anterior/posterior ligamentous disruptions.

Clay shoveler’s fracture

• Oblique fracture of spinous process of lower cervical spine.
• Stability: Stable

Subluxation

• Pure ligamentous injury without associated fracture.
• Imaging: Widening of interspinous and intervertebral spaces on lateral.
• Stability: Potentially unstable.

Bilateral facet dislocation

• Anterior displacement of spine above level of injury caused by dislocation of upper inferior facet from lower superior facet.
• Imaging: Anterior displacement greater than ½ AP diameter of vertebral body.
• Stability: Unstable

Odontoid process fracture

• Head trauma with shear force directed at odontoid.
• Sub-classification: Type I (above transverse ligament), type II (odontoid base), type III (extension to body of C2)
• Stability: Types II, III unstable.

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  Atlantoaxial dislocation

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  Atlanto-occipital dislocation

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  Wedge fracture

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  Flexion teardrop fracture

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  Clay shoveler fracture

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  Facet dislocation

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  Odontoid process fracture

Flexion/Rotation Injuries

Rotary atlantoaxial dislocation

• Imaging: Open-mouth odontoid, asymmetric lateral masses of C1.
• Stability: Unstable

Unilateral facet dislocation

• Flexion and rotation centered around single facet results in contralateral facet dislocation.
• Imaging: AP radiograph shows spinous processes above dislocation displaced from midline, lateral radiograph shows anterior displacement of lower vertebra (less than ½ AP diameter of vertebral body).

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  Unilateral facet dislocation

Extension Injuries

Posterior neural arch fracture (C1)

• Forced extension causes compressive force on posterior elements of C1 between occiput and C2.
• Stability: Unstable

Hangman’s fracture (spondylolysis C2)

• Abrupt deceleration causes fracture of bilateral pedicles of C2, potentially with associated subluxation. Rarely associated with SCI due to large diameter of neural canal at C2.
• Imaging: May be associated with retropharyngeal space edema.
• Stability: Unstable

Extension-teardrop fracture

• Abrupt extension (ex. diving) results in stretch along anterior longitudinal ligament with avulsion of anterior/inferior fragment of vertebral body (usually C5-C7).
• Imaging: May be radiographically similar to flexion-teardrop fracture.
• Complications: Central cord syndrome
• Stability: Unstable in extension

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  Posterior neural arch fracture

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  Hangman's fracture

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  Extension-teardrop fracture

Vertical compression

Burst fracture

• Force applied from above or below causes transmission of force to intervertebral disc and vertebral body.
• Imaging: Comminuted vertebral body, >40% compression of anterior vertebral body.
• Complications: Fracture fragments may impinge on spinal cord.
• Stability: Stable

Jefferson fracture (C1)

• Vertical force transmitted from occipital condyles to superior articular facets of atlas, resulting in fractures of anterior and posterior arches.
• Imaging: Widening of predental space. Open-mouth odontoid view may reveal bilateral offset distance of >7mm between lateral masses of C1/C2.
• Stability: Unstable

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  Burst fracture

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  Jefferson fracture

References

1. MD RK, MD BED, CAQ-SM KHM, MD WF. Emergency Department Evaluation and Treatment of Cervical Spine Injuries. Emergency Medicine Clinics of NA. 2015;33(2):241-282. doi:10.1016/j.emc.2014.12.002.
2. Denis F. Spinal instability as defined by the three-column spine concept in acute spinal trauma. Clin Orthop Relat Res. 1984;(189):65-76.
3. Munera F, Rivas LA, Nunez DB, Quencer RM. Imaging evaluation of adult spinal injuries: emphasis on multidetector CT in cervical spine trauma. Radiology. 2012;263(3):645-660. doi:10.1148/radiol.12110526.