Introduction: We present an unusual case of traumatic occult lateral mass fracture of the cervical spine with unilateral occlusion of the vertebral artery (VA), that was missed by plain X-ray and magnetic resonance imaging (MRI), but identified by computed tomography (CT) after suspecting high-energy trauma as the underlying cause.
Case presentation: A 67-year-old male was injured in a car accident and came to our institute on foot 4 days after injury with complaints of neck pain and numbness in the right hand. Although, no specific bone injury was visible on plain X-ray, the absence of flow voids in the right VA was confirmed on axial T2-weighted MRI. We suspected high-energy trauma of the cervical spine at that point and performed CT for a more detailed assessment. Consequently, a fracture was detected in the right lateral mass of C6 and we speculated that spontaneous reduction of the fracture-dislocation had occurred. One-stage surgery with posterior fixation was subsequently performed for instability. The patient's preoperative symptoms were improved and neither recanalization of the occlusion nor another VA occlusion was observed after surgery.
Discussion: VA injury occurs frequently as a complication of blunt cervical spine trauma. In the present case, however, the lateral mass fracture was not seen on MRI and missed until the unilateral VA injury was detected. When high-energy trauma of the cervical spine is suspected, it is important to evaluate damage to the spinal cord, bone, soft-tissue, and VA by MRI and CT.