Review Question - QID 216260

The patient presents a C1 floating lateral mass with symptoms that are suggestive of a vertebral artery injury (VAI). The next best step is to obtain a CT angiogram of the cervical spine to assess the status of the vertebral arteries.

VAI in patients with cervical spine trauma is a marker of severe injury. Accordingly, VAI are associated with occipitocervical dissociation and basilar skull fractures. As a result of the anatomic location of the vertebral artery, fractures displaced 1mm or greater in the vertebral foramen are also associated with VAIs. VAI can lead to neurological events with devastating sequelae. Risk factors associated with neurologic events related to VAIs include male gender, facet subluxations/dislocations, ankylosing spondylitis (AS), and diffuse idiopathic skeletal hyperostosis (DISH). Common presenting symptoms include vertigo, diplopia, blindness, ataxia, nausea, and oropharyngeal dysfunction. A CT angiogram can identify these injuries following cervical spine trauma.

Lebl et al. reviewed 1204 patients with cervical spine trauma, of which 253 underwent screening for VAI by multidetector computed tomography angiogram. VAI was diagnosed in 17% of the patients. The authors identified high-risk factors for VAI or neurological events secondary to VAI, which include: basilar skull fractures, occipitocervical dissociation, fractures in patients with AS/DISH, facet subluxation/dislocations, and fracture displacement 1mm or greater into the transverse foramen. Hangman’s fractures (P=0.993) were not associated with VAI.

Dreger et al. reviewed 637 patients with cervical spine fractures with 108 undergoing CTA/MRA. Fifteen patients (13.8%) were diagnosed with VAI and 4 underwent treatment. The authors suggest that further research is needed to develop cost-effective evaluations and treatments for VAIs associated with cervical spine fractures.

Figure A is an axial CT of the cervical spine with a floating lateral mass due to the presence of unilateral anterior and posterior ring fractures.

Incorrect Answers:
Answer 1: The patient presents a possible vertebral artery injury, which is associated with occipitocervical dissociation. Applying traction prior to further clinical work-up can potentially lead to lethal consequences.
Answer 2: Cervical spine radiographs can be useful for dynamic instability and assessing for occipitocervical dissociation. Given the patient's neurologic symptoms a CT angiogram of the cervical spine is warranted to assess for a VAI.
Answer 4 and 5: Prior to proceeding with surgical treatment, an assessment for underlying vertebral artery injury should be performed.