颈椎椎弓根皮质骨螺钉固定的钉道影像学测量与生物力学研究测试

Imaging measurement and biomechanical study of cortical screws of cervical pedicle

中文关键词:  皮质骨螺钉  椎弓根螺钉  拔出力  生物力学

英文关键词:Cortical bone screws  Pedicle screw  Withdrawal force  Biomechanics

中文摘要:

  【摘要】 目的：探讨颈椎椎弓根皮质骨螺钉在临床使用可行性、钉道的参数和置钉后生物力学分析。方法：随机选取我院2014年1月～2018年6月住院行颈椎CT三维重建的住院患者CT资料30例，男性16例，女性14例，年龄30～60岁（48.0±5.6岁），采集患者颈椎（选取C4～C6）CT连续扫描数据，测量每个椎弓根的形态学数据：椎弓根高度和宽度；并在图像处理系统上模拟皮质骨螺钉的钉道轨迹，测量每个钉道的侧倾角和头倾角，计算各个椎体皮质骨螺钉置入的角度范围。选用18具完整的成人新鲜颈椎标本（选取C4～C6），将每一节段颈椎标本左右两侧椎弓根各作为一个测试单元进行随机置钉，置入传统椎弓根螺钉为A组，置入皮质骨通道的螺钉为B组。再将置好螺钉的颈椎标本进行CT平扫，测量并记录A、B组螺钉的平均固定长度，根据Grade标准评估置钉等级。将颈椎标本固定在特制的夹具上，生物力学测试前通过旋转夹具底座的方法来调整螺钉与夹具的角度，检测螺钉的最大垂直轴向拔出力，比较两组结果。结果：30例住院患者C4高度为7.3±0.8mm、宽度为5.5±0.3mm；C5高度为7.4±0.6mm、宽度为5.8±0.2mm；C6高度为7.6±0.6mm、宽度为6.2±0.3mm。模拟置钉测量C4侧倾角为39.5°±2.3°、头倾角为10.3°±0.4°；C5侧倾角为39.3°±1.3°、头倾角为10.9°±0.5°；C6侧倾角为37.6°±0.9°、头倾角为11.7°±0.3°。新鲜颈椎标本CT扫描重建，两组螺钉Grade置钉等级，A组1级52枚，2级2枚，B组1级51枚，2级3枚，差异无统计学意义（P>0.05）。A组的平均固定长度C4为34.2±1.8mm，C5为34.3±2.3mm，C6为34.6±1.9mm；B组的平均固定长度C4为23.3±1.4mm，C5为24.3±2.1mm，C6为25.7±1.3mm，差异无统计学意义（P>0.05）。A组最大拔出力为521.2±15.6N；B组最大拔出力为527.4±18.9N；两组的最大拔出力差异无统计学意义（P>0.05）。结论：CT扫描、图像模拟显示颈椎皮质骨螺钉置入安全可行；颈椎皮质骨螺钉的拔出力与传统椎弓根骨螺钉相比，固定长度差异不大，拔出力相当。

英文摘要:

  【Abstract】 Objectives： To investigate the feasibility of cervical pedicle cortical bone screw in clinical use, the selection of screw insertion points, the parameters of screw insertion direction, and the biomechanical analysis after screw insertion. Methods: Randomly select the CT data of 30 patients hospitalized in our hospital from January 2014 to June 2018 who have undergone cervical CT three-dimensional reconstruction. There are 16 males and 14 females, aged 30-60 years (48.0±5.6 years). The data of cervical vertebrae (C4-C6) CT continuous scans were collected, and the morphological data of the height and width of each pedicle were measured. The angle range of cortical screw placement in each vertebral body was calculated by simulating the cortical screw roll angle and head inclination angle on the image processing system. Measure each The lateral inclination angle and head inclination angle of the screw are calculated and the angle range of each vertebral cortical bone screw placement is calculated. Select 18 complete adult fresh cervical spine specimens (select C4-C6), use the left and right pedicles of each cervical spine specimen as a test unit for random placement of screws, and place traditional pedicle screws as group A. The screws placed in the cortical bone channel belong to group B. Then, all cervical spine specimens with traditional cervical pedicle screws and pedicle cortical bone screws were scanned by CT, and the levels of nail placements were evaluated according to the Grade standard. Fix the cervical spine specimens with traditional pedicle screws and pedicle cortical screws on a special fixture. Before the biomechanics test, adjust the angle between the screw and the fixture by rotating the fixture base, and detect the maximum vertical axis of the screw. To pull out force, compare the results of the two groups. Results: The heights and widths of C4, C5 and C6 were respectively 7.3±0.8mm and 5.5±0.3mm, 7.4±0.6mm and 5.9±0.2mm, and 7.6±0.6mm and 6.2±0.3mm. In the cortical screw group, C4 roll angle was 39.5°±2.3°, head inclination angle was 10.3°±0.4°; C5 roll angle was 39.3°±1.3°, head inclination angle was 10.9°±0.5°; C6 roll angle was 37.7°±0.9°, head inclination angle was 11.7°±0.3°. In group A, 52 cases of traditional pedicle screw placements were performed in level 1 and 2 in level 2; while in group B, 51 cases of pedicle cortical screwplacements were in level 1 and 3 in level 2. The difference was not statistically significant(P>0.05). The average fixed length C4 of group A was 34.2±1.8mm, C5 was 34.3±2.3mm, and C6 was 34.6±1.9mm; the average fixed length of group B was 23.3±1.4mm, C5 was 24.3±2.1mm, and C6 was 25.7±1.3mm, the difference was not statistically significant(P>0.05). The maximum extraction force of the traditional cervical pedicle screw group was 521.2±15.58N, and that of the pedicle cortical screw group was 527.41±18.93N, with no significant difference between the two groups(P>0.05). Conclusions: CT scan shows that cervical cortical screw technique is safe and feasible; the extraction force of cervical cortical screw is equivalent to that of traditional pedicle screw. Cortical screw can be clinically used as a new and safe cervical pedicle screw.