High-Riding Vertebral Artery in Cervical Spine Surgery: A Review of Preoperative Identification and Surgical...

High-riding vertebral artery (HRVA) is an important anatomical variant of the vertebral artery that poses significant challenges during cervical spine surgery, particularly at the C1-C2 level, where it reduces the safe corridor for pedicle screw placement and increases the risk of arterial injury. This narrative review summarizes current evidence regarding the definition, prevalence, imaging identification, and surgical implications of HRVA, along with risk mitigation strategies. Radiographically, HRVA is most commonly defined by reduced C2 isthmus height (C2IsH) (≤5 mm) and/or internal height (C2InH) (≤2 mm) on computed tomography (CT) scans. Reported prevalence varies widely across populations, typically ranging from 10% to 25%, with higher rates observed in selected patient cohorts. The presence of HRVA necessitates careful perioperative planning, including comprehensive imaging and modification of surgical techniques, such as the use of alternative fixation strategies, including pars screws, laminar screws, navigation-assisted instrumentation, and artery mobilization. Advances in CT angiography (CTA), alternative fixation strategies, surgical navigation, and emerging predictive models may further improve risk stratification and operative safety. Recognition of HRVA and tailored surgical planning are essential to minimize the risk of vertebral artery injury (VAI) and to optimize patient outcomes in cervical spine surgery and instrumentation.