Schramm J, Mokrusch T, Fahlbusch R, Hochstetter A
Neurochirurgische Klinik, Universität Erlangen-Nürnberg, West Germany.
Neurosurgery. 1988 Apr;22(4):694-702. doi: 10.1227/00006123-198804000-00013.
A series of 31 neurosurgical procedures in the posterior fossa monitored intraoperatively with ipsilateral brain stem acoustic evoked potentials (BAEPs) is analyzed for intraoperative potential changes. The evaluation of patients included pre- and postoperative BAEP recordings and pure tone audiometry. The series included 25 tumors, 4 neurovascular decompressions, 1 basilar artery aneurysm, and 1 arteriovenous malformation. Two intraoperative findings correlated significantly with a postoperative decrease in hearing: an amplitude reduction of more than 50% for Waves I to V and the loss of one of the waves, even if it was a wave that first appeared intraoperatively. We could attribute no significance to reversible or irreversible latency increases for all waves. The transient loss of one of the peaks followed by its reappearance was also insignificant with regard to postoperative hearing. A good prognostic sign was the intraoperative appearance of a peak undetectable on the preoperative recordings. These findings suggest that in intraoperative BAEP monitoring the observation of amplitude reduction is more important than that of latency increases. The surgeon should be informed when an amplitude reduction of more than 50% occurs before the peak is lost totally, as it is impossible to predict whether this peak will reappear intraoperatively.
对31例在后颅窝进行的神经外科手术系列进行分析，这些手术术中采用同侧脑干听觉诱发电位（BAEP）监测，以观察术中电位变化。对患者的评估包括术前和术后的BAEP记录以及纯音听力测定。该系列包括25例肿瘤、4例神经血管减压术、1例基底动脉瘤和1例动静脉畸形。有两项术中发现与术后听力下降显著相关：I至V波的波幅降低超过50%以及其中一个波消失，即使该波是术中首次出现的波。对于所有波的可逆或不可逆潜伏期延长，我们认为无显著意义。某一波峰短暂消失后又重新出现，这对于术后听力而言也无显著意义。一个良好的预后迹象是术中出现术前记录中未检测到的波峰。这些发现表明，在术中BAEP监测中，观察波幅降低比观察潜伏期延长更为重要。当波峰完全消失之前波幅降低超过50%时，应告知外科医生，因为无法预测该波峰是否会在术中重新出现。
