C2 traumatic spondylolisthesis (Hangman’s Fracture)
Findings:
Sagittal reconstructions from cervical spine CT demonstrates bilateral C2 pars interarticularis fractures associated with significant anterior subluxation at C2-3. The axial images again demonstrate the multiple fractures.
Differential Diagnosis:
None other than fracture really applicable, but anterior subluxation at C2-3 on radiographs in children may be physiologic. Apparent C2-3 subluxation may also be caused by other traumatic abnormalities including a unilateral C2 arch fracture. Congenital C2 pars defects are very rare, but would be expected to be well corticated.
Discussion:
-uncommon fracture pattern (7% of cervical fractures)
-hyperextension w axial loading or forced hyperflexion w compression
-rare w hanging injury, almost all w MVA or fall
-look for other C spine fractures (33%), especially C1
-CTA/MRA to exclude VA injury
-grading: I- nondisplaced, II- displaced/angulated, III- II + facet dislocation
-autodecompression of canal w less neurologic injuries than might expect (still 25%)
-Rx w immobilization and fusion.
-risk of delayed stroke if VA injury