F波监测面神经功能评估价值实验研究

目的 探讨F波监测对听神经瘤压力模型大鼠面神经功能评估的价值.方法 对58例模型及对照组SD大鼠行面神经F波监测,记录其潜伏期、波幅及与M波比值(F/M);继而行生物素化葡聚糖胺(BDA)面神经逆行示踪,计数面神经核BDA阳性神经元标记率(BDA+-N%);光、电镜检查小脑脑桥角池段面神经;统计分析F/M与BDA+-N%的相关性,并探讨与面神经病理改变的关系.结果 与两对照组比较,小-大各肿瘤组F波潜伏期延长或部分丢失,F/M依次为77.13%,48.91%和11.54%(P<0.001);BDA+-N%依次为77.28%,48.28%和11.55%(P<0.001).各组F/M与BDA+-N%呈线性正相关(r=0.996,P<0.001).面神经光、电镜观察显示病损随球囊体积增大逐渐加重.结论 面神经F波改变可以用于评估面神经功能完整性,反映其病损程度,应有助于术中面神经监测和术后功能预测.

Experimental study on the value of F wave recording in evaluating the Integrity of facial nerve function

Objective To explore the value of F wave recording in evaluating the integrity of facial nerve function in the pressure-induced rat models of acoustic neurinomas. Method 58 rats in different groups were conducted facial nerve F wave recording and biotinylated dextran amine (BDA) retrograde tracing in their right whisker muscles one week after establishing models. Analyzing their latencies,amplitudes and F/M rates. 72 hours after BDA injection, the rats were infused with 4% polyoxymethylene,then pontine samples and facial nerves in the CPA cistern were obtained. Pontines were cut into 30μm frozen sections for histochemical staining with avidin-horseradish peroxidase (HRP)-DAB and Nissl' s counterstaining, calculating the positive BDA neurons ratio( BDA+ -N% )in facial nuclear. Facial nerves were cut and stained with toluidine blue for light-microscope inspection, and/or stained for transmission electron microscope observation. Correlating F/M with BDA'-N% and the facial nerve pathological findings. Results F waves can be induced and kept stable in control groups when stimulus are between 0.9-2.5mA. F/M are 97.66% and 97.48% in normal and pseudo-operation group, respectively, when stimulus are 1.4mA; while 77.13%, 48.91% and 11.54% in from small to large tumor model groups(P <0. 001 ) because F waves were delayed in latencies or partly lost. Similarly, BDA+-N% are 98.37% and 97.96% in above two control groups, while 77.28%, 48.28% and 11.55% in from small to large tumor model groups ( P < 0. 001 ). Thus F/M are positively correlated with their own BDA+ -N% in all groups (r = 0. 996, P < 0. 001 ). Facial nerve examinations under light and electron microscope show increasing pathological changes along with increasing "tumor" size. Conclusions The findings of F wave recording in facial nerve may reflect its functional integrity or severity to damage. Therefore, F wave detection may help electrophysiological monitoring during acoustic neurinoma resection and facial nerve function evaluation after surgery.