The cervical spine is a dynamic structure tasked with protecting nervous innervation to the entire body while also maintaining range of motion for the head and neck. Fractures of the cervical spine are a leading cause of mobility and mortality in trauma patients, and a bone fracture is associated with 56% of cervical spinal cord injuries. Fractures of the cervical spine can be described based on the level involved and typically divided into three groups: C1, C2 and the sub-axial spine (C3 to C7).
Fractures of the cervical spine result from abnormal movement or a combination of movements including hyperflexion, hyperextension, rotation, axial loading, and lateral bending of the spinal column.
C1 fractures typically result from axial loading. C2 fractures typically occur due to a combination of compression, hyperflexion, and hyperextension. Subaxial cervical spine fracture is commonly seen with high impact accidents such as motor vehicle accidents.
Examination of a patient with cervical spine fractures should begin with a thorough trauma examination of ABCs (check of the airway, breathing, and circulation). Injury to the cervical spine has the potential to compromise respiratory and cardiovascular function and even once stabilized these patients must be closely monitored for the ongoing possibility of changes in the respiratory and cardiovascular function. Next, formal strength and sensation testing of the upper and lower extremities, as well as rectal tone and palpation of the cervical spine should be performed. This is most commonly done following the ASIA scoring system. Acute spinal cord injury is important to identify as early decompression within 24 hours can increase the chance of neurological recovery.
Indications for cervical spine imaging includes localized neck pain, deformity, edema, altered mental status, head injury, or neurological deficit. Computed tomography is the preferred imaging in acute spine trauma as it is more sensitive for detection of bony cervical spine injury when compared to plain radiographs (sensitivity of 98% versus 52%). Further evaluation of ligamentous structures of the spinal cord with MRI is important for determining spinal stability and in planning surgical treatment. Scoring systems in dealing with cervical spinal cord injury that includes ligamentous, bony and neurologic injury exist, a common one is called SLICS (Subaxial Cervical Spine Injury Classification System), and this can be used to help with evaluation and guidance of surgical or nonsurgical management. A SLICS score of 1 to 3 is nonsurgical, a score of 4 is not specified, and a score of 5 or greater is a surgical indication. The scoring system is as follows:
Continuous Cord Compression
Injuries to C1 and C2 compose approximately 30% of cervical spine fractures. Fractures of C1 occur through the lateral mass or arch in single or multiple places (multiple arch fractures, Jefferson fracture). Neurological injury rarely results from an isolated C1 fracture due to abundant space surrounding the spinal cord. C1 fractures may be managed in a rigid cervical collar or halo if the transverse alar ligament (TAL) remains intact on MRI. If the TAL is disrupted C1 to C2 posterior fusion should be considered.
C2 fractures can result in fracture through the body, dens, or pars. If the fracture extends bilaterally through the pars interarticularis, a Hangman’s fracture is described. Hangman's fracture with less than 3mm of displacement and no significant angulation may be treated in a hard cervical collar. If the fracture is displaced greater than 3mm or with greater than 11 degrees of angulation, reduction with halo placement or surgical fixation should be considered. Associated disruption of the C2 to C3 disc with a hangman's fracture requires surgical fixation. Fracture through the C2 dens can be classified as type I, II, or III. Type I is avulsion of the dens tip, type II is a fracture through the base of the dens, and type III is a fracture extending into the C2 vertebral body. Type I and III fractures should be treated in a rigid cervical collar or halo. Type II fractures without risk of nonunion can be considered for hard cervical collar or halo. Risk factors for nonunion include 5mm or more of displacement, greater than 10 degrees of angulation, or age older than 50. Type II fractures at risk for nonunion should be considered for odontoid screw placement or posterior C1 to C2 fusion. All fractures of the C1 to C2 complex are considered unstable and should be treated initially with a hard cervical collar, and then evaluated by a spine surgeon.
Subaxial cervical spine fractures follow similar patterns at each level. Compression fractures result in loss of anterior vertebral body height without canal compromise or neural injury. Burst fractures are a variant of compression fractures that result in retropulsion of the vertebral body into the cervical canal. Of note, C7 burst fractures carry a higher risk of developing kyphotic deformity that other levels of the subaxial cervical spine. Teardrop fractures occur with flexion or flexion-extension of the cervical spine leading to an anterior–inferior fracture of the vertebral body. There are also three column fractures extending through the anterior vertebral body all the way through to the posterior ligaments, and these are highly unstable. Unilateral facet fractures are controversial, but many are highly unstable or can lead to progressive deformity and warrant surgical evaluation. Any fracture extending into the foramina transversarium from C2 to C6 should be evaluated for the possibility of co-occurring vertebral artery injury. Surgical fixation of subaxial cervical spine fractures should take into consideration the SLICS scoring system as previously described.
Clay shoveler’s fractures describe fractures of the cervical spinous processes.
Each fracture described should warrant cervical collar placement with surgery indicated for restoration of cervical lordosis, decompression of the spinal cord, or fixation as determined by the instability of ligamentous components.
Cervical spine fractures are high-risk injuries with the potential for devastating neurological sequelae. Hence, a trained spine specialist should carry out subsequent evaluation and treatment. All patients with cervical fractures should be closely monitored with a follow-up to ensure continued cervical stability and healing. Any fracture extending into the foramina transversarium from C2 to C6 should be evaluated for the possibility of co-occurring vertebral artery injury. This is most often done with CT angiogram.