听神经瘤患者BAEP特征和术中面听神经保留情况分析

Characteristics of brainstem auditory evoked potential and preservation of facial and auditory nerves in patients with acoustic neuromas

目的分析听神经瘤（AN）患者脑干听觉诱发电位（BAEP）特征和显微外科手术中面、听神经保留情况。方法安徽医科大学附属省立医院神经外科自2006年5月至2009年5月共采用肿瘤切除术治疗76例AN患者，术前术中均进行BAEP检查，分析患者术前、术中BAEP异常情况及AN直径大小与和术后面、听神经保留情况的关系。结果AN患者术前患侧BAEP异常76例（76／76，100％），健侧BAEP异常63例（63／76，82．9％），两侧比较差异有统计学意义（P〈0．05）；术中健侧BAEP异常70例（70／76，92．1％），与术前健侧BAEP异常率比较差异有统计学意义（P〈0．05）；术中健侧BAEP异常与面、听神经的保留分别呈正相关关系（r=0．912，P=0．000；r=0．613，P=0．000）；而AN直径与面、听神经的保留分别呈负相关关系（r=-0．869，P=0．000；r=0．738，P=0．000）。结论术前BAEP检测对AN病变提供诊断依据，术中进行BAEP监测可提高面听神经的保留率，且AN直径越大，面、听神经越难保留。

Objective To study the variational features of the brainstem auditory evoked potential （BAEP） and the preservation of the facial and auditory nerves during the microsurgery in patients with acoustic neuromas （AN）. Methods We retrospectively analyzed the data of 76 patients with AN, admitted to our hospital from May 2006 to May 2009： preoperative BAEP were examined; the peak latency （PL） of I, III and V waves and their interpeak latency （IPL） were noted and compared. The tumors were microsurgicaUy removed under intraoperative electrophysiologic monitoring to preserve the facial and auditory nerves. The relationships between the preservation of facial and auditory nerves and both the tumor size and the utilization of intraoperative monitoring were discussed. Results Before the operation, the 100% abnormal rate of BAEP was showed on the diseased side with the disappearance oflII and V waves as its main features, while 82.9% （63/76） of that was noted on the contralateral side with the IPL ratio of III-V / I-HI greater than or equal to 1 as its main features; the BAEP features between the 2 sides had statistical significance （P〈0.05）. Seventy patients （92.1%） were found abnormal of BAEP on the contralateral side during the operation; the BAEP features of the contralateral side had statistical significance between preoperation and intraoperation （P〈0.05）. The tumors were totally removed in 69 （90.8%）, subtotally removed in 6 （7.9%） and partially removed in 2 （1.3%）. The preservation of facial and auditory nerves increased obviously through monitoring the response of BAEP during the surgery and a positive correlation was observed between the preservation of facial and auditory nerves and the response of BAEP in the contralateral side（r=0.912, P=0.000; r=0.613,P=-0.000）. However, an inverse correlation was observed between the preservation of facial and auditory nerves and the size of AN （r=-0.869, P=0.000; r=-0.738, P=0.000）. Conclusion Preoperative BAEP can help to make an exact diagnosis on patients with AN and the preservation of facial and auditory nerves can increase obviously through monitoring the normal response of BAEP during the surgery. The anatomy preservation of facial and auditory nerves depends on the size of AN.