C2 Lateral Mass Fractures

Patients often present with neck pain, limited range of motion, and no neurologic injury.

The mechanisms of injury are axial compression and lateral bending.

A CT scan is helpful for a 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 injury, in which the patient may experience bilateral pedicle fractures and complete disruption of disc and ligaments between C2 and C3.

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 olisthetic 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; frank dislocation; extremely rare

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

fracture fixation and/or possible anterior fusion.