下颈椎前路椎弓根皮质骨螺钉的解剖学研究

Anatomical study of anterior pedicle cortical bone screw in lower cervical spine

目的测量正常成人下颈椎椎弓根的解剖学参数,探讨下颈椎前路椎弓根皮质骨螺钉内固定技术的可行性。方法随机选取80例正常成人颈椎CT影像资料,将扫描数据导入MIMICS 19.0软件。测量C_(3)~C_(7)椎体的椎弓根宽度(OPW)、椎弓根高度(OPH)、内侧皮质骨厚度(MCT)以及颈前路椎弓根皮质骨螺钉置钉参数,进行统计学分析。结果各节段左右两侧OPH和MCT参数的差异有统计学意义(P<0.05)。测量男性的OPH和OPW参数均大于女性,差异有统计学意义(P<0.05)。C_(3)~C_(4)进钉点位于椎体正中矢状面椎弓根的对侧1.0~3.0 mm,距椎体上终板平面1.0~3.5 mm;C_(5)进钉点位于椎体正中矢状面椎弓根同侧或对侧1.0~2.0 mm,距椎体上终板平面3.0~4.0 mm;C_(6)~C_(7)进钉点位于椎体正中矢状面椎弓根的同侧2.0~4.5 mm,距椎体上终板平面4.5~7.0 mm。C_(3)~C_(7)的皮质骨螺钉总体内倾角平均值分别是:39.13°、41.00°、40.91°、37.28°、31.84°,总体矢状角是:90.85°、97.23°、108.97°、111.60°、104.83°。螺钉的直径为3.5 mm,长度选择30 mm,32 mm较为适宜。结论下颈椎前路椎弓根皮质骨螺钉内固定技术在理论上具有可行性,并总结出置钉规律,为其下一步的临床应用提供了理论依据。

Objective To investigate the feasibility of cortical bone trajectory for cervical anterior transpedicular screw fixation(ATPS)by measuring the anatomical characteristics of lower cervical pedicle.Methods Eighty sets adult healthy cervical specimens were randomly selected,and the scanned date were imported to the MIMICS 19.0 software.The following parameters in C_(3)~C_(7) vertebrae:outer pedicle width(OPW)of vertebral body,outer pedicle height(OPH)of vertebral body,medial cortical shell thickness(MCT)of the pedicle,and the cortical bone screw parameters of ATPS were measured and analyzed statistically.Results There were significant differences in OPH and MCT between two sides of each segment(P<0.05).The OPH and OPW of each segment in males were greater than those of in females,with statistical differences(P<0.05).The entry point for C_(3) and C_(4) was 1.0-3.0 mm contralateral to the pedicle in the midsagittal plane of vertebra body,1.0-3.5 mm from the upper end plate of vertebra body.The C_(5) entry point was 1.0-2.0 mm ipsilateral or contralateral to the pedicle in the midsagittal plane of vertebra body,3.0-4.0 mm from the upper end plate of vertebra body.The entry point for C_(6) and C_(7) was 2.0-4.5 mm ipsilateral to the pedicle in the midsagittal plane of vertebra body,4.5-7.0 mm from the upper end plate of vertebra body.At the cortical bone trajectory,the mean values of overall leaning angles from C_(3) to C_(7) were 39.13°,41.00°,40.91°,37.28°,and 31.84°respectively,the mean values of overall sagittal angles from C_(3) to C_(7) were 90.85°,97.23°,108.97°,111.60°,and 104.83°respectively.For ATPS,the diameters of cortical bone screw was 3.5 mm and the inserted length was 30 mm or 32 mm.Conclusions The cortical bone trajectory is a theoretically feasible option for ATPS,and the parameters inserting screw are established,which provides theoretical basis for its further clinical application.