Hayashi Hironobu, Kawaguchi Masahiko, Abe Ryuichi, Yamamoto Yuri, Inoue Satoki, Koizumi Munehisa, Takakura Yoshinori, Furuya Hitoshi
Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan.
J Anesth. 2009;23(2):175-81. doi: 10.1007/s00540-008-0733-0. Epub 2009 May 15.
Recent evidence has indicated that post-tetanic motor evoked potentials (p-MEPs) can be used to improve the reliability of the monitoring of motor function during spinal surgery. However, data on p-MEP monitoring are limited to those in subjects under propofol anesthesia. The present study was conducted to assess the applicability of sevoflurane during p-MEP monitoring in patients undergoing spinal surgery.
Thirty-five patients undergoing spinal surgery under sevoflurane anesthesia were enrolled in the study and classified as being without preoperative motor deficits (n = 25) or with preoperative motor deficits (n = 10). For conventional MEP (c-MEP), transcranial train-pulse stimulation was delivered and the compound muscle action potentials were bilaterally recorded from the abductor pollicis brevis, abductor hallucis, tibialis anterior, and soleus muscles. For p-MEP, tetanic stimulation (50 Hz, 50 mA stimulus intensity) for 5 s was applied to the bilateral median and left tibial nerves 1 s prior to transcranial stimulation.
The amplitudes of p-MEP were significantly higher in all muscle recording sites than those of c-MEP in patients without motor deficits, whereas these amplitudes were significantly higher in only four of the eight muscles in patients with motor deficits (P < 0.05). The success rates of c-MEP and p-MEP recording were 48% and 64%, respectively, in patients without motor deficits and 30% and 60%, respectively, in patients with motor deficits. There were no statistically significant differences in success rates between c-MEP and p-MEP recording.
Although the application of tetanic stimulation prior to transcranial stimulation did not significantly increase the success rates of MEP recording, it significantly enlarged MEP amplitude under sevoflurane anesthesia in patients without preoperative motor deficits.
最近有证据表明，强直后运动诱发电位（p-MEP）可用于提高脊柱手术中运动功能监测的可靠性。然而，关于p-MEP监测的数据仅限于接受丙泊酚麻醉的受试者。本研究旨在评估七氟醚在脊柱手术患者p-MEP监测中的适用性。
35例在七氟醚麻醉下接受脊柱手术的患者纳入本研究，分为术前无运动功能障碍组（n = 25）和术前有运动功能障碍组（n = 10）。对于传统运动诱发电位（c-MEP），进行经颅串脉冲刺激，并从双侧拇短展肌、拇展肌、胫前肌和比目鱼肌记录复合肌肉动作电位。对于p-MEP，在经颅刺激前1秒，对双侧正中神经和左侧胫神经施加5秒的强直刺激（50 Hz，50 mA刺激强度）。
在无运动功能障碍的患者中，所有肌肉记录部位的p-MEP波幅均显著高于c-MEP，而在有运动功能障碍的患者中，仅8块肌肉中的4块肌肉的p-MEP波幅显著更高（P < 0.05）。无运动功能障碍患者的c-MEP和p-MEP记录成功率分别为48%和64%，有运动功能障碍患者的成功率分别为30%和60%。c-MEP和p-MEP记录成功率之间无统计学显著差异。
虽然在经颅刺激前施加强直刺激并未显著提高运动诱发电位记录的成功率，但在术前无运动功能障碍的患者中，七氟醚麻醉下强直刺激显著增大了运动诱发电位波幅。
