Yasuda Muneyoshi, Nakura Takahiro, Kamiya Taeko, Takayasu Masakazu
Department of Neurosurgery, Aichi Medical University, Aichi-gun, Aichi, Japan.
Neurol Med Chir (Tokyo). 2011;51(3):253-5. doi: 10.2176/nmc.51.253.
A 38-year-old male was referred because of pain in the left 5th lumbar (L5) root territory. Physical examination found moderate motor weakness in the left extensor hallucis longus (EHL) and the left tibialis anterior muscles. Magnetic resonance imaging found no stenotic lesion between L4-L5, but disc herniation was observed on the left between L1-L2. An L5 nerve root block provided temporary relief of the pain but the left foot weakness was exacerbated. Therefore, surgery was performed. Partial laminectomy and left herniotomy were performed at L1-L2, L2-L3, and L3-L4 with motor evoked potential (MEP) monitoring. The MEP amplitude of the left EHL muscle increased immediately after L1-L2 herniotomy. The MEP amplitude of the right EHL muscle also increased after both laminectomy and herniotomy. The postoperative course was uneventful. The left leg pain and motor weakness disappeared. The patient has been doing fine without recurrence for 12 months. Since the MEP of both left and right EHL muscles improved after the L1-2 herniotomy, circulatory insufficiency might have caused the L5 symptoms. Monitoring of the MEP during the surgery was useful for confirming the responsible lesion and also for predicting the postoperative course.
一名38岁男性因左腰5（L5）神经根区域疼痛前来就诊。体格检查发现左侧拇长伸肌（EHL）和左侧胫骨前肌有中度运动无力。磁共振成像显示L4 - L5之间无狭窄病变，但在L1 - L2左侧观察到椎间盘突出。L5神经根阻滞暂时缓解了疼痛，但左脚无力加重。因此，进行了手术。在运动诱发电位（MEP）监测下，于L1 - L2、L2 - L3和L3 - L4进行了部分椎板切除术和左侧疝修补术。L1 - L2疝修补术后，左侧EHL肌的MEP波幅立即增加。椎板切除术和疝修补术后，右侧EHL肌的MEP波幅也增加。术后过程顺利。左腿疼痛和运动无力消失。患者12个月来情况良好，无复发。由于L1 - 2疝修补术后左右两侧EHL肌的MEP均有改善，循环功能不全可能导致了L5症状。手术期间对MEP的监测有助于确定责任病变，也有助于预测术后病程。
