Jahangiri Faisal R, Minhas Mazhar, Jane John
Division of Neurology, Department of Medicine, King Abdulaziz Medical City, King Fahad National Guard Hospital, Riyadh, Saudi Arabia.
Neurodiagn J. 2012 Dec;52(4):320-32.
We present two cases illustrating the benefit of utilizing intraoperative neurophysiological monitoring (IONM) for prevention of injuries to the lower cranial nerves during fourth ventricle tumor resection surgeries. Multiple cranial nerve nuclei are located on the floor of the fourth ventricle with a high risk of permanent damage. Two male patients (ages 8 and 10 years) presented to the emergency department and had brain magnetic resonance imaging (MRI) scans showing brainstem/fourth ventricle tumors. During surgery, bilateral posterior tibial and median nerve somatosensory evoked potentials (SSEPs); four-limb and cranial nerves transcranial electrical motor evoked potentials (TCeMEPs); brainstem auditory evoked responses (BAERs); and spontaneous electromyography (s-EMG) were recorded. Electromyography (EMG) was monitored bilaterally from cranial nerves V VII, IX, X, XI, and XII. Total intravenous anesthesia was used. Neuromuscular blockade was used only for initial intubation. Pre-incision baselines were obtained with good morphology of waveforms. After exposure the floor of the fourth ventricle was mapped by triggered-EMG (t-EMG) using 0.4 to 1.0 mA. In both patients the tumor was entangled with cranial nerves VII to XII on the floor of the fourth ventricle. The surgeon made the decision not to resect the tumor in one case and limited the resection to 70% of the tumor in the second case on the basis of neurophysiological monitoring. This decision was made to minimize any post-operative neurological deficits due to surgical manipulation of the tumor involving the lower cranial nerves. Intraoperative spontaneous and triggered EMG was effectively utilized in preventing injuries to cranial nerves during surgical procedures. All signals remained stable during the surgical procedure. Postoperatively both patients were well with no additional cranial nerve weakness. At three months follow-up, the patients continued to have no deficits.
我们报告两例病例，阐述了在第四脑室肿瘤切除手术中利用术中神经生理监测（IONM）预防下颅神经损伤的益处。多个颅神经核位于第四脑室底部，存在永久性损伤的高风险。两名男性患者（年龄分别为8岁和10岁）就诊于急诊科，脑部磁共振成像（MRI）扫描显示脑干/第四脑室肿瘤。手术过程中，记录了双侧胫后神经和正中神经体感诱发电位（SSEPs）、四肢及颅神经经颅电运动诱发电位（TCeMEPs）、脑干听觉诱发电位（BAERs）以及自发肌电图（s - EMG）。双侧对颅神经V、VII、IX、X、XI和XII进行肌电图（EMG）监测。采用全静脉麻醉。仅在初始插管时使用神经肌肉阻滞剂。术前切口基线波形形态良好。暴露第四脑室底部后，使用0.4至1.0 mA的触发肌电图（t - EMG）进行绘图。在这两名患者中，肿瘤均与第四脑室底部的颅神经VII至XII缠绕。基于神经生理监测，一名患者的外科医生决定不切除肿瘤，另一名患者的外科医生将肿瘤切除限制在70%。做出这一决定是为了将因涉及下颅神经的肿瘤手术操作导致的术后神经功能缺损降至最低。术中自发和触发肌电图在手术过程中有效用于预防颅神经损伤。手术过程中所有信号均保持稳定。术后两名患者情况良好，无额外的颅神经功能减弱。在三个月的随访中，患者持续无功能缺损。
