Operative management for atlantoaxial instability in case of bilateral high-riding vertebral artery

In case of atlantoaxial instability dorsal C1-C2 screw fixation is the most appropriate procedure to get immediate and sufficient three-point fixation. However, this method cannot be performed in bilateral high-riding vertebral arteries because of high risk of VA injury. In a 66-year-old woman who presented with neck pain due to atlantoaxial instability bilateral high-riding VAs were detected in CT. To avoid VA injury a dorsal stabilization procedure with a hook-rod system and interspinous autologous iliac crest graft was performed. The intra- and postoperative courses had no complications and the hook-rod construction clinically led to immediate postoperative stability. After 24 months the patient was painfree. In case of atlantoaxial instability and bilateral high-riding VAs dorsal C1-C2 fixation procedure with a hook-rod system and interspinous bone grafting seems to be an appropriate alternative surgical technique and can get immediate and clinically sufficient stability with no risk of VA injury.