正常儿童胸椎椎弓根的参数测量

Pedicle morphology of the immature thoracic spine

目的测量不同年龄儿童胸椎椎弓根参数，确立不同年龄儿童胸椎椎弓根的各种参数变化，为儿童胸椎椎弓根螺钉内固定提供参数依据。方法利用CT二维重建技术，测量120例不同年龄组儿童胸推椎弓根内外径、椎弓根高度、椎弓根长度、横断面夹角。结果①椎弓根横径从T1到T4逐渐减小，T5到T12逐渐增大，最窄者是T4或T5；②椎弓根高度从T1到T12逐渐增大，除T1外，各节段椎弓根高度均明显大于横断面内径；③椎弓根后缘皮质沿其轴线到椎体前缘的椎弓根长度各个年龄组中最长为T12，从T1到T12逐渐增加；④椎弓根横断面夹角最大为T1，从T1到T8逐渐减小，T11、T12为负角。椎弓根长度随年龄的变化较大，而横断面夹角随年龄变化较小。结论对于生长期儿童进行胸椎椎弓根螺钉固定时，可根据不同年龄不同节段椎弓根各种参数变化，结合X线片或CT片，选择相应的螺钉直径、长度、进钉方向。

Objective To quantify the morphometric characteristics of the pedicles of immature thoracic spine. Methods A total of 120 patients, including 60 males and 60 females, aged from 5 to 14 years. All of the patients underwent standard spiral computed tomography. The patients were grouped according to age： Group 1 （5 to 8 years old）, Group 2 （9 to 11 years old） and Group 3 （12 to 14 years old）. Images were reconstructed, and the thoracic pedicles were displayed on sagittal, coronal, and transverse planes. The inner and outer pedicle diameters were measured on the transverse plane, pedicle sagittal diameter was measured on the sagittal plane, pedicle length and the pedicle angle were measured on the transverse plane. Results （1）Transverse pedicle diameters decreased gradually from T1 to T4, and then increased gradually from T5 to T12. The shortest transverse diameter of the thoracic pedicle was that of T4 or T5 ; （2）Pedicular sagittal diameter increased from T1 to T12, and it was obviously longer than transverse diameter except T1 ;（3）The length from posterior cortex to anterior cortex of the vertebra increased from T1 to T12 ; （4）The pedicle angle decreased gradually from T1 to T8 and was negative below the level of T10. The pedicle length increased with advancing age, and the pedicle angle was revealed a slightly variation throughout growth. Conclusions Pedicle morphology changes with growth. Pedicular morphometric characteristics should be investigated using the radiologic examination for the success of transpedicular fixation on children.