ACR Codes: 3.4
This patientsâ€™ findings may be due to an traumatic injury or perhaps a congenital anomaly. This patient has a significant history of acute trauma, and therefore a causative mechanism of action consistent with the above imaging findings. However, the somewhat sclerotic boarders to the fracture lines combined with the congenital cervical ribs and Spina Bifida at C7 suggest that the C6 defects may also be congenital in nature. Given the pateintsâ€™ complaint of neck tenderness and the significant acute trauma history, it is appropriate to assume the findings are secondary to trauma and treat the patient accordingly.
The most likely mechanism of injury is hyperflexion of the C-spine. All hyperflexion injuries, with the exception of a Clay Shovelerâ€™s fracture, involve disruption of the posterior cervical spine ligament complex. The posterior ligament complex (PLC) consists of the supraspinous, interspinous, and posterior longitudinal ligaments as well as the ligamentum flavum and posterior facet joint capsules.
Common radiographical findings consistent with injury to the PLC include: 1) hyperkyphotic angulation of the C-spine at the level of injury, 2) anterior displacement of the superior vertebral body at level of injury, 3) widening of posterior bony elements, 4) anterior narrowing and posterior widening of involved disk space, 5) forward displacement of superior facets of involved joint level.1
Disruption of bony posterior elements in this case may be due to avulsive forces of PLC during severe flexion, or perhaps due to other directional forces owing to the dynamic forces which would likely be applied to the neck during a motorcycle accident such as this one.
Reference(s): References: 1) Harris, Young Jr., Edeiken-Monroe, Beth; The Radiology of Acute Cervical Spine Trauma, second edition. 1987; 92-112.