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Abstract：
Objective Intraoperative neuromonitoring (IONM) is an acknowledged tool for real-time neuraxis assessment during surgery. Somatosensory evoked potential (SSEP) and transcranial motor evoked potential (MEP) are commonest deployed modalities of IONM. Role of SSEP and MEP in intradural extramedullary spinal cord tumor (IDEMSCT) surgery is not well established. The aim of this study was to evaluate sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and transcranial MEP, in detection of intraoperative neurological injury in IDEMSCT patients as well as their postoperative limb-specific neurological improvement assessment at fixed intervals till 30 days. Materials and Methods Symptomatic patients with IDEMSCTs were selected according to the inclusion criteria of study protocol. On modified McCormick (mMC) scale, their sensory-motor deficit was assessed both preoperatively and postoperatively. Surgery was done under SSEP and MEP (transcranial) monitoring using appropriate anesthetic agents. Gross total/subtotal resection of tumor was achieved as per IONM warning alarms. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and MEP were calculated considering postoperative neurological changes as \"reference standard.\" Patients were followed up at postoperative day (POD) 0, 1, 7, and 30 for convalescence. Statistical Analysis With appropriate tests of significance, statistical analysis was carried out. Receiver-operating characteristic curve was used to find cutoff point of mMC for SSEP being recordable in patients with higher neurological deficit along with calculation of sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and MEP for prediction of intraoperative neurological injury. Results Study included 32 patients. Baseline mean mMC value was 2.59. Under neuromonitoring, gross total resection of IDEMSCT was achieved in 87.5% patients. SSEP was recordable in subset of patients with mMC value less than or equal to 2 with diagnostic accuracy of 100%. MEP was recordable in all patients and it had 96.88% diagnostic accuracy. Statistically significant neurological improvement was noted at POD-7 and POD-30 follow-up. Conclusion SSEP and MEP individually carry high diagnostic accuracy in detection of intraoperative neurological injuries in patients undergoing IDEMSCT surgery. MEP continues to monitor the neuraxis, even in those subsets of patients where SSEP fails to record.
摘要：
目的术中神经监测（IONM）是一种公认的用于手术过程中实时神经轴评估的工具。体感诱发电位（SSEP）和经颅运动诱发电位（MEP）是IONM最常见的部署方式。SSEP和MEP在硬膜内髓外脊髓肿瘤（IDEMSCT）手术中的作用尚未明确。这项研究的目的是评估敏感性，特异性，正预测值，负预测值，以及SSEP和经颅MEP的诊断准确性，在IDEMSCT患者的术中神经损伤的检测以及他们的术后肢体特定的神经系统改善评估中，以固定的间隔直到30天。材料与方法根据研究方案的纳入标准选择有症状的IDEMSCT患者。在改良的麦考密克(mMC)量表上，术前和术后均对患者的感觉运动缺陷进行了评估.在SSEP和MEP（经颅）监测下使用适当的麻醉剂进行手术。根据IONM警告警报，实现了肿瘤的总/次全切除。灵敏度,特异性，正预测值，负预测值，SSEP和MEP的诊断准确性以术后神经系统改变为参考标准进行计算.在术后第0、1、7和30天（POD）对患者进行随访以恢复。统计分析通过适当的显著性检验，进行统计分析。使用受试者-工作特征曲线来找到可在较高神经功能缺损患者中记录SSEP的mMC的截止点，并计算灵敏度。特异性，正预测值，负预测值，以及SSEP和MEP预测术中神经损伤的诊断准确性。结果本研究共32例患者。基线平均mMC值为2.59。在神经监测下，87.5%的患者实现了IDEMSCT总切除.在mMC值小于或等于2的患者亚组中可记录SSEP，诊断准确率为100％。所有患者均可记录MEP，诊断准确率为96.88%。在POD-7和POD-30随访时观察到统计学上显著的神经学改善。结论SSEP和MEP在IDEMSCT手术患者术中神经损伤的检测中具有较高的诊断准确性。MEP继续监测神经轴，即使在SSEP未能记录的患者亚组中也是如此。
