Traumatic vertical atlantoaxial instability: the risk associated with skull traction. Case report and literature review.

Traumatic overdistraction between C1 and C2 may occur when all the ligaments connecting C2 to the skull are ruptured, and may be manifested when an attempt to reduce C1-C2 subluxation is made by means of traction. We describe here the case of a patient with traumatic anterior atlantoaxial dislocation, who developed atlantoaxial vertical dissociation after skull traction using a Gardner-Halo with lb 4.02 (1.5 kg) of weight. The identification of patients who are susceptible to this complication is difficult. In this case, it might have been prevented by avoiding spinal traction. The aim of this report was to show that vertical dissociation may occur in C -C2 anterior dislocation submitted to spinal traction, and that other forms of reduction must be considered to treat these pathologies and avoid this potentially fatal complication.