经颅电刺激运动诱发电位在胸椎管狭窄症手术中的应用价值

Application of intraoperative motor evoked potentials during the surgery for thoracic spinal stenosis

背景:经颅电刺激运动诱发电位(MEP)因其可即时反应术中脊髓功能状态已广泛应用于脊柱手术中,尤以脊柱矫形、颈椎手术多见,而有关胸椎管狭窄症手术中应用MEP的报道相对较少。目的目的:分析胸椎管狭窄症手术中MEP神经功能监测的应用价值和监测效能。方法方法:回顾性分析2012年10月至2016年7月我院进行的47例58次胸椎管减压手术。手术方式主要为后路扩大全椎板切除术、经椎间孔胸椎椎间融合术(TTIF),术中应用MEP进行神经功能监测。监测采用经颅电刺激C3、C4位点,记录外周肌源性MEP。报警阳性诊断标准:排除系统性因素及麻醉相关因素外,与高危操作(减压、cage置入、椎弓根螺钉置入等)相关的波形快速丢失超过80%。结果结果:58次胸椎管减压手术中成功获取可靠术前波形并具有监测价值者47次,检出率为81.0%。真阳性结果3例,其中1例经及时处理后术后无神经功能障碍;2例出现暂时性神经功能障碍,经甲泼尼龙冲击治疗后逐渐恢复。假阳性结果 1例。未出现假阴性结果。MEP监测的敏感度和特异度分别为100%和97.7%,阳性预测值和阴性预测值分别为75%和100%。2例患者术后出现迟发性脊髓损伤,考虑脊髓再灌注损伤,经甲泼尼龙冲击治疗后神经功能逐渐恢复。结论结论:胸椎管狭窄症手术难度大,脊髓损伤风险高,术中应用MEP监测能为手术提供客观的安全评估指标,但术后仍需警惕迟发性脊髓损伤的发生。

Background： Motor evoked potential（MEP） has been widely used in spinal surgeries, especially in spinal deformity surgery and cervical surgery, due to immediate responses to the changes of intraoperative spinal cord function. However, there were few researches on the use of MEP in the surgery for thoracic spinal stenosis. Objective： To investigate the necessity and efficiency of MEP during the surgery for thoracic spinal stenosis. Methods： From October 2012 to July 2016,MEP monitoring was performed simultaneously during 58 thoracic decompression surgeries in 47 patients, such as posterior laminectomy and transforaminal thoracic interbody fusion（TTIF）. C3 and C4（International 10-20 system） were stimulated to elicit MEP and compound muscle action potentials were recorded from distal limbs. MEP warning criteria was defined as rapid loss of more than 80% of the amplitude of the waveform, which was synchronously associated with high-risk operations（decompression, cage implantation, pedicle screw insertion, et al）. Systemic and anesthetic factors were excluded. Re Results： The baseline of MEP monitoring was obtained successfully in 47 decompression surgeries, and the success rate of MEP recording was 81.0%. The MEP result was truly positive in 3 surgeries. No new neurological dysfunction occurred in one patient after treatment in time, and transient neurological deficits were found in 2 patients who were treated by methylprednisolone pulse treatment and recovered gradually. There was one false positive result, while no false negative result.The sensitivity and specificity of MEP monitoring were 100% and 97.7%, respectively. The positive predictive value and negative predictive value were 75% and 100%, respectively. Delayed spinal cord injury occurred in two patients after decompression, which might be caused by ischemia reperfusion injury of spinal cord and was treated by a large dose of methylprednisolone, dehydration and neurotrophic drugs. Conclusions： Thoracic decompression surgery is a kind of difficult and high-risk procedure. MEP can provide objective safety assessment indexes when it is used to monitor neurological function during the surgery, but it is still necessary to pay close attention to the presence of delayed spinal cord injury.