腰椎椎弓根螺钉预出钉部位的影像解剖学研究

目的：探讨腰椎前方大血管与腰椎椎弓根螺钉预出钉部位的位置关系，为腰椎椎弓根螺钉内固定时椎前大血管损伤的预警提供形态依据。方法：对33套成人腰椎标本进行放射解剖学测量，得出腰椎椎弓根螺钉进钉角度与预出钉点位置关系；通过成人120例CT片的相关测量，得出椎前大血管与椎体周缘的位置关系。结果：（1）X线解剖学观测，当进钉角度在0—5°时，出钉点多在椎体侧方0—60°；当进钉角度为5～10°时，出钉点在椎体前外侧方60～70°；当进钉角度为10～20°时，出钉点在椎体前方70～90°。（2）CT观测，在L1～L4椎体水平，腹主动脉大多位于椎体左侧前方70-90°，下腔静脉位于椎体右侧前外侧方50—80°。L5椎体水平，髂部血管位于左、右侧方45～70°。结论：以人字嵴顶点为进钉点行腰椎椎弓根螺钉手术时，在L1～L4进钉角度为0～5°时，预出钉点在椎体前外侧方60～70°可避开椎前大血管，相对安全。左侧较右侧相对安全。在L5进钉角度为10～20°可避开椎前大血管，相对安全。

Imaging Anatomical Study on the Expected Exit Position of Pedicle Screw in Lumbar Fixation

Objective：To discuss the ubiety of the anterior lumbar major vessels and the expected exit positions of lumbar pedicle screw in order to providing a configurative foundation alert of the anterior lumbar major vascular injury in lumbar pedicle screw internal fixation. Methods：The relationship between the expected tip positions and pedicle screw was observed by radiological anatomy study on 33 dry lumbar specimens. The locations of abdominal great vessels around lumbar vertebrae were observed on the lumbar spine CT scans from 120 cases. Results：When the entry angle were 0 -5°, 5 - 10° and 60 -70° respectively, their expected tip position located at the lateral, anterolateral and anterior of vertebral cortex at the angle of 0 - 60° , 60 - 70° and 70 - 90° accordingly. At the transverse plane of L1 - L4, the abdominal aorta was situated at left anterior of the vertebra at the angle of 70 -90°, and the inferior vena cava was at right anterolateral of the vertebra at 50 - 80% At level of L5 , the iliac vessels located at angle of 45 -70° at fight and left sides of the vertebral body. Conclusions ： During the operations on lumbar fixation with pedicle screw, when the entry angle of screw were at 0 -5°and 10 -20° respectively on the transverse plane of L1 - L4 and L5 , the expected exit points of pedicle screw could avoid cutting the major vessels which in the front of vertebral body, especially, when the expected exit point was at left, it would be safer than at right.