脊柱颈胸段前路椎弓根置钉的影像解剖学

Imaging anatomy on anterior transpedicular screw fixation in the cervicothoracic junction

目的：通过影像学研究颈胸段前路椎弓根置钉的相关参数,为临床应用提供依据.方法：选取颈椎及上胸椎螺旋CT扫描完整影像学资料,利用多平面重建技术获得颈胸段椎弓根二维图像.在颈胸段椎弓根水平面像及椎弓根矢状面像上对相关置钉参数进行测量,分析颈胸段前路椎弓根置钉的进针位置及进针方向.结果：颈胸段椎弓根宽度、高度、前路椎弓根螺钉外倾角、尾倾角各椎节间差异有统计学意义.依据矢状面和水平面上椎弓根轴线与椎体前缘的交点集中分布区域,作为最优进钉点所在区域.前路椎弓根螺钉在第6颈椎椎体表面的进针点位于前正中线附近、椎体前缘的2区;在第7颈椎进针点多数位于中线偏拟置钉椎弓根的同侧C区,椎体前缘的2区;在第1胸椎进针点位于中线偏拟置钉椎弓根的同侧C区,以椎体前缘的2、3区为主;在第2胸椎则位于中线偏拟置钉椎弓根的同侧C区,以椎体前缘的3区为主.颈胸段前路椎弓根螺钉进针方向在椎弓根水平面上为外倾46.60°～19.40°,从第6颈椎～第2胸椎逐渐减小;在椎弓根矢状面像上,进针方向均尾倾,尾倾角在10°～25°.不同节段前路椎弓根螺钉进针点及进针方向存在一定差异,且置钉方向存在胸廓入口骨性遮挡的可能.结论：颈胸段前路椎弓根螺钉固定在解剖学上是一项可行的技术,不同椎节间的进钉参数存在差异,需结合实际情况个体化置钉.

Objective： To explore several relevant parameters of anterior transpedicular screw fixation on cervicothoracic junction by radiological studies, and to provide the basis for its clinical application in the future. Methods： From August 2013 to February 2014, 40 patients were scanned in cervical and Upper thoracic spine by spiral CT and multiplannar reformation was used to measure the related parameters on anterior cervicothoracic pedicle axis view. The related data were statistically analyzed to find the entry point and trajectory of anterior transpedicular screw on cervicothoracic junction. Results： There was statistically significant difference among each segment in AVBH （anterior vertebral body height）, OPW （outer pedicle height）, OPH （outer pedicle height）, TPA （transverse pediele angle） and SPA （sagittal pedide angle）, except PAL （pedicle axis length）. The best entry point was located where the intersection point of the transpedieular axis and anterior vertebral body wall was concentrated on the sagittal plane and horizontal plane. The entry point of C6 was located in the mid-sagittal line and No. 2 area. C7 was mainly found in the C area and No. 2 area. T1 was mainly found in C area and No. 2 and No. 3 area. T2 was mainly found in the C area and No. 3 area. The transverse pedicle angle decreased from C6 （46.10°±2.96°） to T2 （19.40°±3. 48°）. C6-Tg pedicle axis on the sagittal axis all were tilted to caudal side. The sagittal pedicle angles of C6-T2 were in an average of 10° to 25°. The trajectory and entry point of the anterior transpedicular screw in cervicothoracic junction have some differences among each segment, and the screw-setting direction may be limited by bony obstructions of thoracic inlet. Conclusion= Judged from the view of radiography, the technique of anterior transpedicular screw fixation in the cervieothoraeic junction is feasible, but relevant parameters of anterior transpedieular screw placement on cervicothoracic junction have some differences among each segment and individualized principle should be abided by.