Häusler R, Kasper A, Demierre B
Clinic for ENT, Head and Neck Surgery, Cantonal University Hospital, Geneve, Switzerland.
Acta Otolaryngol. 1992;112(2):180-5. doi: 10.1080/00016489.1992.11665400.
Electrically evoked short latency vestibular potentials were recorded in 9 patients during vestibular neurectomy. Patients were operated on because of intractable Meniere's disease. The VIIIth cranial nerve was exposed through a limited retrosigmoidal approach; the vestibular nerve was contacted in the cerebello-pontine angle with a bipolar platinum-iridium electrode and stimulated with biphasic current pulses (100 microseconds/phase, 0.75-1 mA p-p, 20/s). The responses were recorded over 12.8 ms between a forehead and an ipsilateral ear lobe electrode. Each recording consisted of 2 x 1,000 averaged responses. A systematically reproducible vertex-negative potential occurring at a latency of approximately 2 ms and having an amplitude of approximately 0.5 microV was recorded in all patients. This vertex-negative potential disappeared after selective vestibular neurectomy proximal to the stimulation site. Simultaneous continuous acoustic masking did not affect the response and no facial nerve response was observed on the facial nerve monitoring. These features strongly suggest that the characteristic vertex-negative potential constitutes a specifically evoked response of the vestibular system. Electrophysiological monitoring of the sectioning of the vestibular nerve during operation is one possible clinical application of intraoperative recording of electrically evoked vestibular potentials.
在9例患者进行前庭神经切除术时记录了电诱发短潜伏期前庭电位。这些患者因顽固性梅尼埃病而接受手术。通过有限的乙状窦后入路暴露第八颅神经；在前庭小脑桥脑角用双极铂铱电极接触前庭神经，并用双相电流脉冲（100微秒/相，峰峰值0.75 - 1毫安，20次/秒）进行刺激。在额部和同侧耳垂电极之间记录12.8毫秒内的反应。每次记录由2×1000次平均反应组成。在所有患者中均记录到一个系统可重复的顶点负电位，其潜伏期约为2毫秒，幅度约为0.5微伏。在刺激部位近端进行选择性前庭神经切除术后，该顶点负电位消失。同时进行的连续听觉掩蔽不影响反应，并且在面神经监测中未观察到面神经反应。这些特征强烈表明，特征性的顶点负电位构成了前庭系统的特异性诱发反应。术中记录电诱发前庭电位对手术中前庭神经切断进行电生理监测是一种可能的临床应用。
