神经电生理监测技术在胸腰椎骨折微创椎弓根螺钉置入术中的应用

目的探讨神经电生理监测技术在脊柱微创椎弓根置钉术中的应用价值。方法回顾分析2011年2月~2014年2月浙江省丽水市人民医院骨科收治的胸腰椎爆裂性骨折并行胸腰椎椎弓根置钉术患者资料52例,在经皮置钉过程中实时自发肌电(spontaneous electromyography,s EMG)和触发肌电(triggered electromyography,t EMG)监测、体感诱发电位(somatosensory evoked potential,SEP)检测。随访患者术后临床神经功能及置钉椎体薄层CT。结果术后9例患者SEP波幅较术前波幅升高,提示症状可能较术前改善,术后随访证实麻木感较术前改善。术中抓获暴发肌电3例,确认钉道破壁。222枚螺钉置入中,经CT提示有21枚螺钉穿破椎弓根,t EMG阳性23例,假阳性2例,并且螺钉破壁后位置与t EMG阈值无明显关联。按美国脊髓损伤学会(America spinal injury association,ASIA)分级随访患者神经功能,术前A级2例、B级3例、C级8例、D级30例、E级9例;末次随访A级1例、B级1例、C级2例、D级17例、E级31例,差异具有统计学意义(P0.05)。结论 EMG和SEP有各自的作用,联合监测具有互补作用,为指导脊柱椎弓根镙钉置入术的进程和提高手术安全性起到一定作用。

Application of neurophysiological monitoring in implantation of pedicle screw in thoracolumbar spine surgery

Objective To investigate the application of neurophysiological monitoring in the implantation of pedicle screw in minimally invasive spine surgery. Methods To investigate the 52 patients who need percutaneous implantation of pedicle screw from February 2011 to February 2014. Both spontaneous electromyography(sEMG), stimulus triggered electromyography (tEMG), and somatosensory evoked potential(SEP) were monitored in the process of implantation. Then the cases were followed up with neurological status and the location of pedicle screw by CT. Results The wave amplitude of SEP was increased during intraoperative monitoring in 9 cases. Nine cases showed relieved symptoms of numbness after surgery.EMG was successfully induced and recorded in all the cases. Explosive compound muscle action potentials was found in 3 cases which confirmed the burst of pedicle.CT showed 21 screws piercing the pedicle in the 222 screws.Twenty-three cases show positive EMG while 2 cases showed false positive results. There were no direct relationship between the position of screws pulled out and threshold value of stimulus triggered EMG. According to American spinal injury association(ASIA) score, there were 2 cases rated of Grade A, 3 cases Grade B, 8 cases Grade C, 30 cases Grade D and 9 cases Grade E before operation. In comparison 1 case had Grade A, 1 case had Grade B, 2 cases had Grade C, 17 cases had Grade D and 31 cases had Grade E at final follow-up. Conclusion SEP, especially combined with EMG during spinal surgery can effectively reduce the mechanical damage to the nerves and increase the success rate of implantation of pedicle screw in minimally invasive spine surgery.