个体化数字导航模板在脊柱侧凸手术中的应用研究

Research on the application of individual digital navigation templates in scoliosis surgery

目的评价个体化数字导航模板在脊柱侧凸矫形手术中的应用效果。方法 2013年9月至2014年9月,我院收治67例脊柱侧凸患者,应用计算机进行完全随机化处理,选取11例,其中男5例,女6例,年龄6-17岁,平均12.4岁;特发性侧凸（adolescent idiopathic scoliosis,AIS）6例,先天性侧凸3例,神经肌肉型1例,马方综合征（Marfan’s syndrome）1例;主弯Cobb’s角38°-84°,平均69.6°。进行CT扫描、计算机三维重建、模拟置钉,确定进钉通道,并生成与脊椎后方骨性结构完全匹配的单椎体反向模板,将反向模板与进钉通道结合,生成导航模板,将脊柱模型及导航模板应用快速成型机制作出实物模型,在体外进行置钉试验,后将导航模板应用于术中辅助椎弓根螺钉置入,术后行CT扫描评价椎弓根螺钉位置。结果术前准备时间为31-45 h,平均39.3 h。体外及体内置钉时模板均体现了良好的适配性,置钉均一次成功,未行再次调整。体外置钉试验准确率100%,实际手术中应用导航模板共置入椎弓根螺钉164枚,CT影像分级I级138枚（84.1%）,II级26枚（15.9%）,无III级和IV级螺钉,全部为可接受螺钉,未出现螺钉相关并发症。手术时间80-220 min,平均147 min。出血量200-850 ml,平均575 ml。主弯Cobb’s角从术前的38°-84°（平均69.6°）矫正至术后的6°-31°（平均15.7°）,平均矫正率77.4%。结论应用个体化数字导航模板辅助椎弓根螺钉置入,操作简便,模板稳定性好,置钉准确率高,是提高脊柱侧凸手术安全性的理想方法。

Objective To evaluate the effects of individual digital navigation templates used in scoliosis surgery. Methods From September 2013 to September 2014, 11 out of 67 patients of scoliosis were chosen randomly based on a computer-aided design, including 5 males and 6 females. The average age was 12.4 years old（ range： 6-17 years）. There were 6 cases of adolescent idiopathic scoliosis（ AIS）, 3 cases of congenital scoliosis, 1 neuromuscular case and 1 case of Marfan＇s syndrome. The mean Cobb＇s angle of main curves was 69.6°（ range： 38°-84°）. CT scan was performed on each desired vertebra, and a 3-D reconstruction model was generated based on the CT scan data. The optimal screw size and orientation were determined. A reverse template of a single vertebral body was completely matched with the posterior bony structure of the spine. The reverse template was connnected with the screw channel to generate a navigation template. And then a physical model was manufactured using the spine model and the navigation template by a rapid prototyping technique and tested in vitro. The template was sterilized and used intraoperatively to assist the insertion of pedicle screws. After the surgery, the positions of the pedicle screws were evaluated using CT scan. Results It took a mean period of 39.3 h（ range： 31-45 h） to accomplish the preoperative preparation. The templates all fi tted well both in vitro and in vivo. No screws were adjusted because of the malposition. The accuracy of simulation of pedicle screws in vitro was 100%. A total of 164 pedicle screws were inserted intraoperatively, with 138 screws（ 84.1%） in grade I, 26 screws（ 15.9%） in grade II but no screws in grade III or IV according to the CT image classifi cation. All the screws were acceptable, and there were no screw-related complications. The mean operation time was 147 min（ range： 80-220 min）. The mean blood loss was 575 ml（ range： 200-850 ml）. The mean Cobb＇s angle of main curves was reduced from 69.6°（ range： 38°-84°） preoperatively to 15.7°（ range： 6°-31°） postoperatively. The mean correction rate was 77.4%. Conclusions Individual digital navigation templates can be used to assist the insertion of pedicle screws, which are easy to handle, with high stablity and high accuracy in screw insertion. It is an ideal method to improve the safety of scoliosis surgery.