レボブピバカインとロピバカインを用いた硬膜外麻酔後に遷延性感覚障害と下肢の筋力低下を来した1症例

A Case of Prolonged Sensory Impairment and Lower Limb Weakness after Epidural Anesthesia Using Levobupivacaine and Ropivacaine

要旨

　硬膜外麻酔（穿刺部位T10-11）を併用した結腸切除術後に下肢のしびれと筋力低下，局所麻酔薬曝露の想定部位に近似した感覚低下と筋電図異常を認めた。末梢神経伝導速度は正常なため，除外診断も加味し，原因は硬膜外腔に投与した局所麻酔薬によるT10-L4の脊髄，またはその近傍の神経障害であることが疑われた。

　A patient（75-year-old man, 156 cm, 46 kg）underwent a laparoscopic right hemicolectomy. An epidural needle was uneventfully inserted at T10-11 level. He received intraoperatively three times of 6ml single doses of 0.375％ ropivacaine in 4 hours. Continuous epidural infusion of 0.167％ levobupivacaine was started at the end of surgery.

　Two days postoperatively, he complained of numbness and muscle weakness in the lower limbs. Anesthesia around T10-L1 dermatomes was also detected. The epidural catheter was removed on the third postoperative day. Both needle electromyography and nerve conduction indicated bilateral root disorders at the level of T10-L4. It is assumed that local anesthetic neurotoxicity is the most likely cause for the neurologic damage.