下颈椎侧块螺钉固定安全性的解剖学研究

Evaluation of posterior lateral mass screw fixation by anatomy study

目的 通过解剖学研究 ,确定下颈椎侧块螺钉安全的植入途径。方法 取 2 8具C3～ 7标本 ,解剖确定安全的入、出钉点后摄取C3～ 7各椎体的横断面X线片 ,测量片上C3～ 6横突孔外缘与入钉点连线和矢状轴之间的成角。结果 侧块背面中心内侧 1mm处是安全的入钉点 ,横突与关节突相交处是安全的出钉点。C3～ 6横突孔外缘与入钉点连线和矢状轴成外偏 5～ 12° ,椎体间差异无显著性 (P >0 .0 5 )。结论 颈椎侧块外上象限是螺钉植入的安全区 ,横突与关节突相交处是安全的出钉点。颈椎侧块螺钉置入时保持外倾 15°以上 ,不会损伤椎动脉。

Objective To investigate the safe trajectory of the fixation of cervical lateral mass screw by anatomic study.Methods Twenty-eight cervical specimens (C_ 3-7 ) of human cadavers aged from 28 to 79 years were studied.The safe exit and entrance point of screw were studied.The transverse radiographs of C_ 3-6 vertebrae were taken and the angle between the parasagittal plane and the line connecting the entrance point of the lateral mass with the lateral limit of the transverse process foramen of C_ 3-6 measured.Results The safe trajectory of the screw was drilled starting 1 mm medial to the center of the lateral mass and exited the juncture between the transverse process and the facet.The angles were lateral to the sagittal plane and ranged from 5° to 12°.Among the vertebrae,there was no statistically significant difference ( P >0.05).Conclusion The superior lateral quadrant was the safe area of the cervical lateral mass screw.The safe exit point was the juncture between the transverse process and the facet.There was no risk of damaging the vertebral artery if a screw is directed more than 15° lateral to the sagittal plane at C3-6 starting 1 mm medial to the center of the lateral mass.