神经监测在神经外科中普遍使用，允许手术过程中对大脑的功能通路进行术中评估。监测警示可以实时指导手术决策，帮助外科医生减轻或避免潜在的治疗性损伤，以及可能由脑缺血或灌注不良导致的术后神经学后遗症。在本文中，我们呈现了一个接受右侧翼上切颅手术切除跨越中线肿瘤的病人，使用多模式术中神经监测技术，包括体感诱发电位、经颅磁刺激诱发肌电电位和视诱发电位。在肿瘤切除的最后阶段，注意到未知来源的动脉出血，并紧随其后出现右侧下肢运动诱发电位记录的丢失。右上肢和左上、下肢的运动诱发电位记录稳定，以及所有的体感诱发电位和视诱发电位。右下肢运动诱发电位记录的这种明显丢失模式提示了相对侧前大脑动脉的威胁，指导外科医生进行迅速干预。患者术后苏醒后，受影响肢体出现中度的术后肌力减弱，到第二个术后日变回术前水平，三个月后追踪时回复到正常肌力。本例神经监测数据提示了相对侧前大脑动脉的威胁，进而指导外科医生进行病变血管的检查和鉴别诊断。本例强调了神经监测在急诊手术情况下指导手术决策的实用性。

Neuromonitoring is commonly used in neurosurgery and allows intraoperative assessment of functional pathways in the brain during surgery. Monitoring alerts can guide surgical decision making in real-time allowing surgeons to mitigate or avoid potential iatrogenic injury and subsequent postoperative neurologic sequelae that may result from cerebral ischemia or malperfusion. Here we present a case of a patient undergoing a right pterional craniotomy for the resection of a tumor which crosses midline with multimodal intraoperative neuromonitoring including somatosensory evoked potentials, transcranial motor evoked potentials, and visual evoked potentials. During the final portion of tumor resection, arterial bleeding was noted of unknown origin shortly followed by loss of right lower extremity motor evoked potential recordings. Motor evoked potential recordings in the right upper, and left upper and lower extremities were stable, as well as all somatosensory evoked potentials and visual evoked potentials. This distinct pattern of right lower extremity motor-evoked potential loss suggested compromise of the contralateral anterior cerebral artery and guided the surgeons to a rapid intervention. The patient awoke from surgery with moderate postoperative weakness in the affected limb that resolved to preoperative status by postoperative day 2, and back to normal strength prior to three-month follow-up. In this case the neuromonitoring data suggested compromise to the contralateral anterior cerebral artery which guided the surgeons to investigate and identify the site of vascular injury. The present case reinforces the utility of neuromonitoring in emergent surgical situations to guide surgical decision making.