Hangman’s fracture

Definition #

• Bilateral pars interarticularis fracture of C2 with anterior displacement (spondylolisthesis) of C2 on C3.
• Also called traumatic spondylolisthesis of the axis.

Mechanism of injury #

• Extension + axial loading (classic).
• Flexion-distraction (Type IIA).
• Flexion + compression / distraction in unstable cases.

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The Levine-Edwards classification (the modified Effendi classification) #

• Type I: Vertical pars fracture, ≤ 3 mm displacement, stable.
• Type IA (atypical): Non-parallel bilateral fractures, may involve foramen transversarium.
• Type II: Pars fracture + C2–C3 disc/PLL disruption, > 3 mm displacement, some angulation.
• Type IIA: Oblique fracture, flexion-distraction; traction dangerous.
• Type III: Type II + bilateral C2–C3 facet dislocation; ALL may be injured.

Imaging #

• X-ray: lateral/AP/odontoid views, upright films for displacement.
• CT: gold standard for fracture pattern and displacement.
• MRI: evaluate C2–C3 disc, ligaments, cord, vertebral artery involvement.

Stability Criteria #

• 3–5 mm anterior translation of C2 on C3.
• 10° angulation between C2–C3.
• Disc/PLL/ALL disruption.
• Facet dislocation.
• Atypical line through foramen transversarium → vertebral artery risk.

Treatment #

Nonoperative (stable types):

• Type I, IA → rigid collar 8–12 weeks.
• Type II (minimal displacement/angulation) → collar or halo.

Operative (unstable or failed conservative):

• Type II (> 5 mm translation or > 10° angulation).
• Type IIA → halo (select) or surgery (fusion preferred).
• Type III → posterior C2–C3 fusion (± anterior).
• Surgical options:
  • Posterior C2 pedicle + C3 lateral mass screws.
  • ACDF at C2–C3 if major disc injury.
  • Combined anterior + posterior for severe instability.

Prognosis #

• Type I: > 95% union with collar.
• Type II/IIA/III: higher nonunion risk, often need surgery.
• Mortality/morbidity low if treated appropriately.

Complications #

• Nonunion or malunion (esp. IIa/III).
• Neurological injury (rare, but risk in atypical, IIa, III).
• Vertebral artery injury (if foramen transversarium involved).
• Immobilization issues: halo pin infections, skin sores, pulmonary issues.

Key Points (WFNS & reviews) #

• CT = first-line imaging; MRI if ligament/disc/cord concerns.
• Rigid collars often preferred over halo (fewer complications).
• Surgery recommended for Type IIA, III, or unstable II.
• Elderly: individualized approach (halo poorly tolerated).

References #