儿童寰枢椎脱位经后路置钉固定的临床解剖与应用研究

Clinical anatomy and application of posterior pedicle screw fixation in pediatric atlantoaxial dislocation

目的测量并分析寰枢椎脱位患儿的寰枢椎解剖结构,以指导经后路置钉固定手术。方法分析我院21例寰枢椎脱位儿童的上颈椎影像学资料。基于影像学资料测量患儿寰枢椎侧块及枢椎椎弓根长、宽、高、钉道内倾角和头倾角;观察枢椎椎弓根安全区,并确定手术安全等级。结果寰枢椎脱位患儿颈部后路解剖结构以枢椎椎弓根横径宽度最为狭窄,左侧为(5.19±0.82)mm,右侧为(5.07±2.63)mm;手术置钉角度左侧取(32.19°±5.42°)、右侧取(39.40°±6.73°)较为安全。寰椎两侧长、宽、高及钉道内倾角、头倾角比较差异无统计学意义(P>0.05);枢椎两侧长、宽、高及钉道内倾角、头倾角比较差异无统计学意义(P>0.05);枢椎椎弓根两侧长、宽、高及钉道内倾角、头倾角比较差异无统计学意义(P>0.05)。置钉过程中,42个椎弓根中有25个(59.5%)为椎动脉损伤低风险,14个(33.3%)为椎动脉损伤中风险,3个(7.1%)为椎动脉损伤高风险。部分患儿的椎弓根置钉过程中存在显著的对侧变异。结论寰枢椎脱位患儿颈部后路解剖结构以枢椎椎弓根横径宽度最为狭窄,置钉要求高,应根据此处经线选择螺钉。儿童寰枢椎脱位的后路解剖可指导置钉手术,避免椎动脉损伤及骨质破坏。

Objective To measure and analyze the atlantoaxial anatomy of pediatric patients with atlantoaxial dislocation,so as to guide posterior pedicle screw fixation surgery.Methods The imaging data of upper cervical spine in 21 pediatric patients with atlantoaxial dislocation were analyzed.The length,width,height,internal inclination angle and head inclination angle of screw canal in the lateral mass of atlantoaxial axis and axis pedicle were measured based on the imaging data.The safety zone of axis was observed to determine the safety level of operation.Results Among the posterior anatomical structures of atlantoaxial dislocation in pediatric patients,the width of transverse diameter of axis pedicle was the narrowest,with the left side of(5.19±0.82)mm and the right side of(5.07±2.63)mm;the angles of surgical screw placement with(32.19°±5.42°)on the left side and(39.40°±6.73°)on the right side were safe.There was no statistically significant difference in the length,width,height,internal inclination angle or head inclination angle of screw canal on both sides of atlas(P>0.05);there was no statistically significant difference in length,width,height,internal inclination angle or head inclination angle of screw canal on both sides of axis(P>0.05);there was no statistically significant difference in length,width,height,internal inclination angle or head inclination angle of screw canal on both sides of axis pedicle(P>0.05).During the process of screw placing,25(59.5%)of 42 pedicles had low risk of vertebral artery injury,14(33.3%)pedicles had medium risk of vertebral artery injury,and 3(7.1%)pedicles had high risk of vertebral artery injury.A part of pediatric patients had significant contralateral variation during pedicle screw placement.Conclusion The width of the transverse diameter of axis pedicle is the narrowest in the posterior cervical anatomy of pediatric patients with atlantoaxial dislocation,with a high requirements for screw placement,and the screw should be selected according to the meridian here.The posterior anatomy of pediatric atlantoaxial dislocation can guide screws placement surgery to avoid vertebral artery injury and bone destruction.