Modified posterior atlantoaxial screw-rod fixation in a case of persistent first intersegmental artery. Case report and literature review

Objective This case reports atlantoaxial stabilization in case of V3 segment anomaly. Patient We report the case of a patient who was victim of a complex C2 fracture requiring atlantoaxial stabilization whereas the initial cervical 3D CT angiography showed a persistent first intersegmental artery consisting in a V3 segment of the vertebral artery penetrating dura-mater in the spinal canal below the C1 posterior arch without passing through the C1 foramen transversarium. Results This rare vascular anomaly described in 2 to 5% of the patients led us to modify the screw entrance over the C1 posterior arch in order to obtain a satisfactory stabilization and to limit the risk of vertebral artery injury.