手术治疗陈旧性寰枢椎脱位术中体感诱发电位监测的临床价值

Clinical applications of intraoperative cortex somatosensory evoked potential in the surgery of old atlantoaxial dislocation

目的:探讨手术治疗陈旧性寰枢椎脱位时皮层躯体感觉诱发电位(CSEP)术中监测评价脊髓功能状态的应用价值。方法:对42例陈旧性寰枢椎脱位行手术治疗患者,实施术中CSEP监测,观察并分析皮层体感觉诱发电位的潜伏期及波幅,把相对于基准值的潜伏期延长超过10%和(或)波幅峰值下降50%定为异常判断标准,对患者术前术后均行神经功能检查及JOA评分。结果:CSEP真阴性37例,手术操作完成后其中35例患者波幅升高和(或)潜伏期缩短,术后神经功能较术前有所改善,无新的神经功能受损,其余2例神经功能与术前无明显变化。CSEP真阳性2例,其中1例术者停止正在进行的寰椎后弓减压,麻醉医生给予甲强龙40mg,5min后潜伏期及波幅恢复至正常范围,术后神经功能较术前有所改善;1例出现波幅降低60%,停止螺钉置入操作后波形有所恢复,术后出现右上肢麻木。CSEP假阴性1例,此患者术中波形未见异常,术后出现右下肢肌力减弱,JOA评分较术前降低。CSEP假阳性2例,1例麻醉师给予升高血压后波形恢复正常;1例未查明原因,伤口关闭后波形恢复正常;术后神经功能未受损,JOA评分改善率平均为82%。结论:术中CSEP能较好地反映脊髓功能状态,对预防寰枢椎脱位手术术中脊髓发生不可逆损伤具有重要价值。

Objectives： To investigate the effect of the cortex somatosensory evoked potential（CSEP） on spinal cord function under C1-2 dislocation surgery. Methods： In this study, 42 cases with old atlantoaxial disloca- tion received intraoperative CSEP monitoring. Latency and amplitude of cortical potentials were observed with the value of the latency extension more than 10% and peak amplitude reduction more than 50% defined as abnormality. Preoperative and postoperative JOA score were used to evaluate the neurofunction. Results： True negative rate was 88.1%（37/42）, increased amplitude and （or） latency were noted in 35 cases after operation, and neurological function improved. No new neurological deficit was noted, and the other 2 cases showed no change compared with preoperation. True positive was 4.8%（2/42）, and decompression ceased in 1 case when suffering from abnormality, and the waveform returned to normal after administration of MEP 40mg, neurologi- cal function improved postoperatively. Wave amplitude decreasing 60% was noted in 1 case, and waveform re- turned to normal after ceasing screw placement, right upper limb was noted numbness after operation. False negative was 2.4%（1/42）, this case showed no intraoperative wave abnormality, but postoperative right lower limb weakness was noted, and JOA score decreased compared with preoperation. False positive was 4.8% （2/42）, 1 case had waveform returned to normal after performing hypertension; and the cause for the other one was unidentified, after closing the wound, waveform returned to normal; there was no damage of neurolog- ical function after operation, the improvement rate of JOA score was 82%. Conclusions： CSEP can reflect the functional state and integrity of the spinal cord so as to prevent irreversible damage to the spinal cord duringthe surgery of old atlantoaxial dislocation.