T4～T10经肋椎单元和椎弓根固定相关解剖学参数的数字化测量

Digital measurement of anatomical parameters associated with vertebral units fixed by ribs and pedicle fixation of T4-T10

目的通过数字化三维测量获取T4～T10椎弓根．肋椎单元固定的相关参数，为临床应用提供依据。方法对15例非脊柱疾患成人T4～T10椎体进行螺旋cT扫描，将所得数据导入计算机，通过Mimics16．0软件和Ansys11．0有限元软件建立T4～T10胸椎肋椎单元、椎间盘的有限元模型，利用软件测量经椎弓根一肋椎单元固定组（A组）的椎弓根．肋椎单元横径、椎弓根外螺钉钉道长度、椎弓根外螺钉内倾角、椎弓根外螺钉最大内倾角、椎弓根外螺钉最小内倾角，以及经椎弓根固定组（B组）的椎弓根横径、椎弓根螺钉钉道长度、椎弓根螺钉内倾角、椎弓根螺钉最大内倾角、椎弓根螺钉最小内倾角，并比较A、B组相对应的参数。结果两组的横径、钉道长度随椎序的增加而逐渐增加，而钉道内倾角、最大内倾角、最小内倾角均随着椎序的增加逐渐减小；A组相关参数均大于B组，差异有统计学意义（P〈0．05）。结论在脊柱T4～T10节段，经肋椎单元固定可以为临床手术提供更大的安全置钉角度和螺钉直径，对于降低手术操作的复杂性及提高螺钉把持力具有重要的意义。

Objective To perform digital 3D measurement of anatomic parameters associated with vertebral units fixed by ribs and pedicle fixation of T4-T10, providing evidence for clinical application. Methods Spiral CT scan of T4-T10 vertebrae was conducted in 15 normal adults without spinal disorder. The data were imported into computer to establish units and disc models of thoracic and rib vertebrae T4-T10 using Mimics 16.0 software and Ansys 11.0 finite element software. The following data were measured in the vertebral pedicle-rib unit fixation group （group A） by software： transverse diameter of vertebral pedicle-rib unit, length of the outside pedicle screw, inclination angle of pedicle screw, and maximum and minimum inclination angles of pedicle screw; the following data were also measured in the pedicle fixation group （group B） by software： pedicle transverse diameter, length of pedicle screw, inclination angle of pedicle screw, and maximum and minimum inclination angles of pedicle screw. The corresponding parameters were compared between groups A and B. Results In both groups, the transverse diameters and screw lengths gradually increased with the increase in the vertebral sequence while the inclination angle of pedicle screw, and maxi- mum and minimum inclination angles of pedicle screw decreased with the increase in the vertebral sequence. All the parameters in groups A were significantly larger than the corresponding ones in group B （ P 〈 0, 05 ）. Conclusions Of the spinal segment of T4-T10, the rib vertebral unit fixation can provide greater safe screw angles and screw diameters for clinical surgery. This is of vital significance for reducing the surgical complexity and improving screw prehension.