[C2 pedicle screw insertion assisted by mobilization of the vertebral artery in cases with high-riding vertebral artery].

Objective: To examine the feasibility, safety, and efficacy of mobilization of the vertebral artery for C2 pedicle screws in cases with high-riding vertebral artery (HRVA). Methods: The clinical data of 12 patients with basilar invagination and atlantoaxial dislocation underwent atlantoaxial reduction and fixation in the Department of Neurosurgery, the First Affiliated Hospital of University of Science and Technology of China between January 2020 and November 2021 were retrospectively analyzed. All patients had high-riding vertebral artery on at least one side that prohibited the insertion of C2 pedicle screws. There were 2 males and 10 females aged (48.0±12.8) years (range: 17 to 67 years). After correction of vertical dislocation during the operation, the C2 pedicle screw insertion and occipitocervical fixation and fusion were performed using the vertebral artery mobilization technique. Neurological function was assessed using the Japanese Orthopedic Association (JOA) scale. The preoperative and postoperative JOA score and the main radiological measurements, including the anterior atlantodental interval (ADI), the distance of the odontoid tip above the Chamberlain line, the clivus-canal angle, were collected and compared by paired t-test. Results: Mobilization of the high-riding vertebral artery was successfully completed, and C2 pedicle screws were then fulfilled after the vertebral artery was protected. There was no injury to the vertebral artery during the operation. Meanwhile, no severe surgical complications such as cerebral infarction or aggravated neurological dysfunction occurred during the perioperative period. Satisfactory C2 pedicle screw placement and reduction were achieved in all 12 patients. All patients achieved bone fusion 6 months after surgery. No looseness and shift in internal fixation or reduction loss was observed during the follow-up period. Compared to the preoperative, the postoperative ADI decreased from (6.1±1.9) mm to (2.0±1.2) mm (t=6.73, P<0.01), the distance of the odontoid tip above the Chamberlain line decreased from (10.4±2.5) mm to (5.5±2.3) mm (t=7.12, P<0.01), the clivus-canal angle increased from (123.4±11.1) ° to (134.7±9.6) ° (t=2.50, P=0.032), the JOA score increased from 13.3±2.1 to 15.6±1.2 (t=6.99, P<0.01). Conclusion: The C2 pedicle screw insertion assisted by mobilization of the vertebral artery is safe and considerably effective, providing a choice for internal fixation in cases with high-riding vertebral arteries.目的： 探讨在椎动脉高跨患者中应用椎动脉移位技术辅助枢椎椎弓根螺钉植入的可行性、安全性及有效性。 方法： 回顾性分析中国科学技术大学附属第一医院神经外科2020年1月至2021年11月诊治的12例先天性颅底凹陷合并寰枢椎脱位且伴有椎动脉高跨患者的病例资料。男性2例，女性10例，年龄（48.0±12.8）岁（范围：17~67岁）。术中纠正纵向脱位后，应用椎动脉移位技术，尝试植入枢椎椎弓根螺钉并行枕颈固定融合术。测量术前、术后寰齿间距（ADI）、齿状突尖端超过Chamberlain线的距离、斜坡枢椎角，应用日本矫形外科协会（JOA）颈椎评分评价神经功能。手术前后指标的比较采用配对样本t检验。 结果： 所有患者术中顺利完成高跨侧椎动脉移位，植入枢椎椎弓根螺钉，术中无椎动脉损伤发生，围手术期未发生脑栓塞、神经功能障碍加重等严重手术并发症。术后6个月CT检查结果提示植骨融合均获成功，未见内固定移位、松脱或复位丢失。手术前后对比，ADI从术前的（6.1±1.9）mm降至术后的（2.0±1.2）mm（t=6.73，P<0.01），齿状突尖端超过Chamberlain线的距离从（10.4±2.5）mm降至（5.5±2.3）mm（t=7.12，P<0.01），斜坡枢椎角从（123.4±11.1）°升至（134.7±9.6）°（t=2.50，P=0.032），JOA颈椎评分从（13.3±2.1）分升至（15.6±1.2）分（t=6.99，P<0.01）。 结论： 椎动脉移位技术辅助枢椎椎弓根螺钉植入可行，为椎动脉高跨患者提供了一种内固定选择。.