Bilateral abducens nerve palsy following ligamentous C1-C2 distraction

Posttraumatic abducens nerve palsy is well documented following head injury, but only few case reports exist on sixth nerve palsy after cervical spine trauma. Bilateral abducens palsy following vertical C1-C2 ligamentous distraction has not been described yet. We report two patients who sustained motor vehicle accident-related C1-C2 distraction injury and were diagnosed with posttraumatic bilateral abducens nerve palsy. Patients underwent surgical stabilization of the upper cervical spine and demonstrated a remarkable recovery of the sixth nerve deficit up to 1 year after injury. We hypothesize that ligamentous C1-C2 distraction leads to caudal displacement of the brainstem in relation to the cranial base causing traction injury to the abducens nerve at its entry into Dorello's canal in the cavernous sinus.