术中诱发肌电图刺激值与椎弓根螺钉位置的关系研究

目的:探讨术中诱发肌电图刺激值与椎弓根螺钉至椎体后壁内侧之间距离的关系.方法:对33例闭合性腰椎骨折患者行后路椎弓根螺钉固定,并采用Endeavor术中神经监护仪对椎弓根螺钉进行电流刺激并记录刺激值,术后通过CT平扫及重建,确定每个椎弓根螺钉植入的位置并测量螺钉与椎体后壁内侧之间的距离.对诱发肌电图刺激值与相应椎弓根螺钉至椎体后壁内侧之间的距离进行线性回归分析,并建立回归方程.结果:33例患者共置入132枚椎弓根螺钉,其中5枚椎弓根螺钉置入失败,建立的回归预测方程为Y=5.22 +2.22X(t =5.479,P=0.003).结论:术中诱发肌电图监测对于最大限度地保证椎弓根螺钉准确置入、避免神经根损伤具有重要意义.利用建立的回归方程,术者可以在术中实时了解和评估椎弓根螺钉的位置,从而有效提高椎弓根置钉的成功率,减少神经损伤.

Study on the relationship between stimulus values of intraoperative evoked electromyography and the position of pedicle screws

Objective:To explore the relationship between stimulus values of intraoperative evoked electromyography and the distance between pedicle screw and medial posterior wall of vertebral body.Methods:Thirty-three patients with closed lumbar fracture were administrated with posterior fixation of pedicle screw,then their pedicle screws were stimulated by current with the help of Endeavor neuromonitoring instrument,and the stimulus values were recorded.After the operation,the position of pedicle screws were determined and the distance between screw and medial posterior wall of vertebral body was measured through CT scan and reconstruction.Linear regression analysis was made on the values of intraoperative evoked electromyography and distance between the relevant pedicle screw and medial posterior wall of vertebral body,and the corresponding regression equation was also established.Results:There were 132 pedicle screws implanted into lumbar vertebrae of 33 patients in total,while 5 screws were found to be failed in the implantation.The predicting equation of regression was established as Y^ =2.22x+5.22(t=5.479,P=0.003).Conclusion:Intraoperative evoked electromyography monitoring has great importance on the maximum assurance of accurate implantation of pedicle screw without nerve root injury.With the help of the established regression equation,surgeon can effectively improve the success rate of screw implantation in pedicle with lower probability of injuring the never root through real-time understanding and estimation of the pedicle screw position during the operation.