个性化导航模板辅助儿童颈椎椎弓根螺钉置入与徒手置入准确性的对比研究

Comparative study of the accuracy of children cervical pedicle screw placement between personalized navigational template and free hand placement

目的 ：探讨个性化导航模板辅助儿童颈椎椎弓根螺钉置入的可行性及准确性,并与徒手置钉进行对比。方法：选取儿童尸体4具,男女各2具,年龄6-9岁。随机分为2组,均行颈椎椎弓根螺钉置入术。徒手置钉组（A组）行徒手置钉;个性化导航模板辅助下置钉组（B组）依据颈椎CT扫描资料,利用计算机辅助及快速成型技术设计并制作出相应颈椎椎弓根螺钉置入个性化导航模板,行该模板辅助下置钉。置钉后行颈椎CT扫描评价两种置钉方法的置钉成功率及优级率并行统计分析。结果：A组共置入28枚螺钉,寰椎置入4枚螺钉,其中良级3枚、差级1枚;枢椎置入4枚螺钉,其中优级2枚、良级2枚;下颈椎（C3-C7）置入20枚螺钉,其中优级9枚、良级5枚、差级6枚。B组共置入28枚螺钉,寰椎置入4枚螺钉,其中良级2枚、差级2枚;枢椎置入4枚螺钉,其中优级3枚、良级1枚;下颈椎置入20枚螺钉,其中优级16枚、良级3枚、差级1枚。两组上颈椎的置钉成功率及优级率因样本数太少未进行统计学比较;两组下颈椎置钉的成功率及优级率均有统计学差异（P〈0.05）。结论 ：个性化导航模板辅助儿童下颈椎椎弓根螺钉置入术具有较好的置钉成功率,该方法操作简单、易于掌握,充分体现了儿童置钉个性化原则。

Objectives： To explore the feasibility and accuracy of personalized navigational template in children cervical pedicle screw placement and compare it with free hand pedicle screw placement. Methods： 4children（2 boys and 2 girls） corpses were randomly divided into two groups, with the range of age of 6-9years old. Patients in group A underwent free hand pedicle screw placement, while group B underwent personalized navigational template, according to pre-operative CT results, the personalized navigational template was established by reverse engineering and rapid prototyping, then the template was referenced to pedicle screw implantation. Subsequently, CT scan was performed to evaluate the screw orientation and accuration.Results： A total of 28 pedicle screws was implanted in group A, 4 pedicle screws were implanted in C1, 3screws showed no critical breaches and 1 screw showed critical breaches; 4 pedicle screws were implanted in C2, 2 screws were placed entirely within the pedicle and 2 screws showed no critical breaches; 20 pedicle screws were implanted into the lower cervical spine pedicle, 9 screws were entirely within the pedicle, 5screws showed no critical breaches and 6 screws showed critical breaches. A total of 28 pedicle screws was implanted in group B, 4 pedicle screws were implanted into the atlas, 2 screws showed no critical breaches and 2 screws showed critical breaches; 4 pedicle screws were implanted in C2, 3 screws were entirely within the pedicle and 1 screw showed no critical breaches; 20 pedicle screws were implanted int lower cervical spine pedicle, 16 screws were entirely within the pedicle, 3 screws showed no critical breaches and 1 screw showed critical breaches. Due to the limited samples, the success and excellent rate of screw placement in upper cervical spine showed no difference between two groups, while showed significant difference（P〈0.05） in lower cervical spine between two groups. Conclusions： Children lower cervical spine pedicle screw placement assisted by personalized navigational template is highly accurate and simple.