枢椎椎弓根骨折半螺纹螺钉固定长度的影像学研究

 目的影像学测量枢椎椎弓根不同部位骨折后路半螺纹螺钉的固定长度。方法收集2007年6月至2013年6月收治非Hangman骨折致寰枢椎损伤汉族患者的影像学资料,枢椎椎体及关节突间部（椎弓根）骨折者均以排除,共160例患者资料纳入研究,男120例,女40例;年龄18~72岁,平均41.4岁。在ADW 4.4工作站行CT三维重建,选取枢椎椎弓根钉道设计图像,以Ebraheim法确定枢椎进钉点,测量自进钉点经枢椎椎弓根最狭窄部位中点至枢椎体前方皮质骨后缘的距离（半螺纹螺钉长度）;模拟临床常见的三种枢椎椎弓根骨折（经椎体后壁骨折、经峡部骨折、经椎板前缘骨折）的骨折线,分别测量自进钉点至骨折线的距离（螺杆长度)和自骨折线至枢椎椎体前方皮质骨后缘的距离（螺纹长度）。观察身高、性别、不同部位骨折半螺纹螺钉长度、螺杆长度及螺纹长度的规律。结果男性身高162~177 cm,平均（167±7.9） cm;女性身高151~167 cm,平均（156±6.6） cm。枢椎椎弓根骨折后所需半螺纹螺钉长度男性平均（28.8±3.2）mm;女性（24.7±2.6） mm,男性半螺纹螺钉较女性长（t=6.50,P< 0.05）。患者身高与半螺纹螺钉长度呈正相关（r=0.667,P<0.01）。骨折线越靠近枢椎体后壁半螺纹螺钉的螺杆越长、螺纹越短,经椎体后壁骨折组螺杆长度男性平均17 mm、女性15 mm,螺纹长度男性平均12 mm、女性10 mm;经峡部骨折组螺杆长度男性平均14 mm、女性13 mm,螺纹长度男性平均15 mm、女性12 mm;经椎板前缘骨折组螺杆长度男性平均10 mm、女性9 mm,螺纹长度男性平均18 mm、女性15 mm。结论枢椎椎弓根骨折后路手术中使用的半螺纹螺钉长度与身高、性别有关。椎弓根骨折部位不同,所需半螺纹螺钉的螺杆、螺纹长度也不相同。

An imaging study of partially-threaded screw fixation of C2 pedicle fracture

ObjectiveTo observe the imaging features of partiallythreaded screw fixation using in various kinds of C₂ pedicel fracture. MethodsCT image materials of 160 Chinese Han patients who suffered from atlantoaxial injury without vertebral body and pedicle fracture of C₂ was included in this study, including 120 males and 40 females. Pedical trajectory selected according to Ebraheim method in threedimensional CT reconstruction was analyzed in ADW 4.4 workstation. The posterior wall fracture of C₂ vertebral body,isthmus fracture and fractures under C₂ laminar were simulated according to clinical observation. The trajectory length (partiallythreaded screw length) from entry point to anterior cortical bone of C₂, bolt shank length from entry point to fracture line and fillet of screw length from fracture line to anterior cortical bone of C₂ were measured. Relations between height, gender and partiallythreaded screw length bolt shank and fillet of screw length was evaluated. ResultsMale height was 167±7.9 cm on average, and female was 156±6.6 cm. The length of partiallythreaded screw was 29 mm in male and 25 mm in female on average. Height and gender was positively correlated with partiallythreaded screw length. In posterior wall fracture of C₂ vertebral body, length of bolt shank was an average of 17 mm in male and 15mm in female, while fillet of screw length was 12 mm in male and 10 mm in female. The mean length of bolt shank was 14mm in male and 13 mm in female, while mean fillet of screw length was 15 mm in male and 12 mm in female in isthmus fracture. In fractures under C₂ laminar, length of bolt shank was 10 mm in male and 9 mm in female on average, while mean fillet of screw length was 18 mm in male and 15mm in female. ConclusionThe length of partiallythreaded screw used in posterior axial pedicle fracture may have a close correlation to length and height. The length of bolt shank and fillet of screw was different according to the position of the fracture.