成人胸椎椎弓根横径对螺钉植入安全性的影响

目的：评价成人上位、中位胸椎节段（T1～T8）椎弓根形态对螺钉植入安全性的影响。方法：采用大体直接测量方法，测量5具新鲜成人尸体胸椎（T1～T8）椎弓根的横径，比较其与临床应用的胸椎椎弓根螺钉的匹配程度；模拟手术情况，按照个体化原则选择植入螺钉型号，并于直视下植入椎弓根螺钉，肉眼下观察螺钉植入后椎弓根皮质破坏情况。结果：成人胸椎T6～T8节段，椎弓根横径分别为4.53（4.40～4.70）、5.38（5.25～5.60）和5.55（5.50～5.80）mm，均>4.5　mm，可以满足最小直径螺钉植入。T1～T5椎弓根横径分别为4.74（3.85～5.25）、4.47（3.45～5.25）、4.15（3.60～4.65）、3.75（3.10～4.50）和4.25（3.70～4.65）mm。在所有测量胸椎标本中，椎弓根横径<4.5 mm的椎体占标本总体的22.5％。螺钉植入椎弓根后，2个椎体发生椎弓根外侧皮质破坏。结论：成人T3～T4节段椎弓根横径最窄，影响椎弓根螺钉的安全植入，但在上位及中位胸椎的大部分节段，可以安全植入。

Influence of pedicle transverse diameter on security of screw implantation in adult thoracic vertebrae

Objective To identify the effect of morphology of adult upper and middle thoracic pedicle on security of screw implantation.Methods Five fresh adult cadaveric thoracic spine from T1 to T8 were harvested.Pedicle transverse diameters were measured and compared with the smallest diameter(4.5 mm) of screw used in clinic.The screws were inserted and implant effect was observed.Results The mean transverse diameter of adult thoracic(T1-T8) were T1:4.74(3.85-5.25)mm,T2:4.51(3.45-5.25)mm,T3:4.15(3.60-4.65)mm,T4:3.75(3.10-4.50)mm,T5:4.25(3.70-4.65)mm,T6: 4.53(4.40-4.70)mm,T7:5.38(5.25-5.60)mm,T8:5.55(5.50-5.80)mm.Of all specimens,there were 9 specmen(22.5%) whose tranverse diameters were smaller than 4.5 mm.After implantation,two screws broke through pedicle lateral wall.Conclusion Adult pedicle transverse diameters in T3-T4 are smallest,transpedicular screw placement is difficult in some of these vertebrae,but in most of thoracic vertebrae,pedicle tranverse diameter could permit screw implanting in security.