面神经监测在小儿电子耳蜗植入术中的应用

Application of facial nerve monitoring in pediatric cochlear implantation

目的评价面神经监测在小儿电子耳蜗植入术中的作用并细化其监测方法,探讨满足小儿面神经监测的麻醉方案。方法20例行电子耳蜗植入术的婴幼儿和20例行鼓室成形术的成人患者,术中行面神经实时监测,七氟醚复合瑞芬太尼静脉滴注维持。根据直视下面神经暴露程度,分为面神经暴露组和未暴露组2个亚组,测定面神经诱发肌电位的电刺激阈值。结果所有病例均成功诱发面神经肌电位反应,且术后面神经功能均未见异常。电子耳蜗组面神经水平段的刺激阈值:暴露组为(0.38±0.10)mA,未暴露组为(1.21±0.32)mA;垂直段的刺激阈值:暴露组为(0.40±0.14)mA,未暴露组为(0.91±0.17)mA。电子耳蜗组各亚组刺激阈值均显著高于鼓室成形术组(P值均<0.05)。结论电子耳蜗植入术中面神经监测有助于定位与保护面神经。定位未暴露的面神经时,先用1.0 mA刺激,再用1.5 mA探寻;面神经暴露时,用0.3 mA开始刺激。七氟醚复合瑞芬太尼可以满足电子耳蜗植入术患儿面神经监测的需求。

Objective To evaluate and refine facial nerve monitoring(IFNM)in pediatric cochlear implantation and to investigate the general anesthetic effects of sevoflurane combined remifentanil.Methods IFNM was performed in 20 patients undergone cochlear implantation and 20 patients undergone tympanoplasty.General anesthesia was maintained with sevoflurane combined remifentanil.All the patients were divided into two subgroups,facial nerve exposure group(group A)and unexposure group(group B).The stimulating thresholds of facial nerve evoked electromyography(EEMG)responses were recorded.Results All the patients displayed detectable EEMG responses.The facial nerve function remained well postoperatively.The stimulating threshold of facial nerve EEMG was(0.38±0.10)mA in group A vs(1.21±0.32)mA in group B at the horizontal segment of facial nerve and(0.40±0.14)mA in group A vs(0.91±0.17)mA in group B at the vertical segment of facial nerve.The differences of threshold were significant between the two groups(P<0.05).Conclusions Intraoperative facial nerve monitoring is a helpful adjunct for surgeon to identify and map the facial nerve,and provides precaution to avoid iatrogenic facial nerve injury.It is recommended an electric stimulation of 1 mA for the first screening and 1.5 mA for the second exploration in order to define the facial nerve in pediatric cochlear implantation.If the facial nerve is exposed,stimulation should be started from 0.3 mA.Sevoflurane combined remifentanil could provide reliable conditions for intraoperative facial nerve monitoring in pediatric cochlear implantation.