A die should be designed to minimize any strip distortion which would tend to change the distance between pilot holes ( alter the progression). 模具设计应保证最少的任何改变料带步距的料带扭曲。
Methods: The pedicle screw pilot holes were drilled within the center of the pedicle, violated pedicle walls in9 human dried thoracic vertebrae. 目的:建立判定胸椎椎弓根螺钉植入孔道是否准确的新方法。
Objective: To evaluate the accuracy of cervical pedicle screw pilot holes placement by bilateral oblique X-ray films with the spiral wires as the guide pin. 目的:探讨螺旋形导针配合双侧斜位X线片判断颈椎椎弓根螺钉置入孔道准确性的可行性。