大型听神经瘤术中监测电刺激强度与面神经预后关系分析

Relationship between intensity of electrical stimulates and prognosis of facial nerve:intrao-perative monitoring of 130 large acoustic neuromas

目的 :了解面神经监测的方法学以及术中监测时的电刺激强度和面神经预后的关系 ,在实现解剖保留面神经的基础上 ,分析影响面神经预后的因素。方法 :报告了 130例听神经瘤 ,12 9例采用枕下乙状窦后入路 ,1例采用经迷路入路。术中使用Viking IV型多导术中监测仪 ,监测自发和诱发面肌肌电图。结果 :通过术中监测自发EMG结合单极恒压电刺激诱发EMG可以精确判断面神经的位置 ,面神经解剖率为 94 6 1%。刺激量由大到小 ,距离由远及近 ,可以准确定位面神经。结论 :长期随访发现诱发面肌肌电图的刺激强度与面神经功能呈负相关 ,阈刺激或接近阈刺激可诱发出肌电图者面神经功能恢复理想。

Objective:The aim of intraoperative monitoring is to preserve facial nerve and other cranial nerves at the basis of total tumors removal. The key elements of facial nerve preservation was analyzed.Methods: We reported 130 cases of large acoustic neuromas with intraoperative multimodality monitoring of facial nerve, acoustic nerve and trigeminal nerve. The 129 patients underwent operation with retrosigmoid approach,1 patient with translabyrinth approach. Results: Constant monopolar voltage stimuli can identify the position of facial nerve excisely. The electrical injury to facial nerve is smaller than that of mechanic stimulate. The stimulate intensity is from low to high step by step and the distance to nerve is from remote to vicinity.The ratio of facial nerve preservation is 94.61%.Conclusions: The electrical stimulate can identify the position of facial nerve quickly and precisely. Stimulate at the exit of facial nerve from brainstem can predict the acute and final facial nerve function following acoustic neuroma resection. If the stimulate is 1V(0.1ms), the facial nereve function is I grade of Housr-Brackman classification at discharge and numbers of H-B grade I patients increased greatly following up in 1 year later.