骶二椎弓根钉内进钉固定拔出力与骶骨应变分布规律的实验研究

目的研究骶二椎弓根钉固定拔出力与骶骨应变分布规律，为临床骶二椎弓根钉固定术提供生物力学参数。方法取正常人新鲜尸体骶骨标本，以椎弓根钉内进钉方法固定于骶二椎弓根，于电子万能试验机上进行相应力学测试，并利用动静态电阻应变仪对预先粘贴在四个椎弓根螺栓固定边缘部位和骶骨不同部位的应变片进行测量。结果得出了椎弓根钉的最大拔出力为（514．5±9．4）N，发生在2号钉位置；最大应变发生在1号钉，其最大应变为（168．5±5．8）X10一。结论骶二椎弓根钉内进钉固定应变分布合理，有利于平衡和稳定。

Experimental Studies on Fixation Pulling-out Force of the Second Sacral Enter Pedicle Screw and Strain Distribution of the Sacrum

Purpose To study fixation pulling-out force of sacral Ⅱ pedicle screw and the strain distribution of sacral, and provide biomechanical parameters for clinical fixation method of sacral II. Methods we got sacrum specimens from fresh corpses of normal people, fixed in the second sacral pediele by the method of enter pedicle screw. Then we carried the sample on the Shimadzu electronic universal testing machine and tested the palling out force . At the same time, we used the strain gauge to measure the strains of four fixed-site edge of Pedicle and the different parts of sacrum using the resistance strain gauge. Results We got the biggest pulling-out force of the pedicle screw was （514.5± 9.4）N,which happened in the nail on the 2nd position The maximum strain occurred at the Ist nail, and the maximum strain was （ 168.5 ±5.8） ×10-6. Conclusion The strain distribution resulted from the methoed of second sacral pedicle screw into nails fixation is reasonable and conducive to balance and stability.