Intraoperative cochlear nerve monitoring in microvascular decompression of hemifacial spasm and resection of vestibular schwannoma
10.3760/cma.j.cn115330-20230913-00088
- VernacularTitle:蜗神经监测在半面痉挛显微血管减压和前庭神经鞘瘤切除术中的应用比较
- Author:
Xiuying WANG
1
;
Jiao CONG
;
Jun ZHANG
;
Ding ZHANG
;
Chong LI
Author Information
1. 解放军总医院神经外科医学部，北京 100853
- Keywords:
Hemifacial spasm;
Vestibular schwannoma;
Cochlear nerve;
Action potentials;
Evoked potentials, auditory, brain stem;
Monitoring, intraoperative
- From:
Chinese Journal of Otorhinolaryngology Head and Neck Surgery
2023;58(12):1225-1231
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the application of direct cochlear nerve monitoring technology-cochlear nerve action potential (CNAP) monitoring in resection of vestibular schwannoma (VS) and to compare with which in microvascular decompression (MVD) of hemifacial spasm (HFS), in order to provide reference for identification of the cochlear nerve during VS resection surgery and predicting postoperative hearing preservation.Methods:From June 2018 to March 2022, patients with facial spasm and vestibular schwannoma who underwent retrosigmoid approach surgery at the Chinese PLA General Hospital were collected. Before surgery, there were a total of 11 HFS patients and 30 VS patients. Before surgery, the former had hearing level of class A(AAO-HNS), while the latter had serviceable hearing (AAO-HNS class A-B), with a maximum tumor diameter of≤20 mm. CNAP combined with Auditory Brainstem Response (ABR) monitoring was performed during surgery. SPSS 23.0 software was used to analyze the differences of ABR and CNAP parameters between the two groups.Results:The preoperative ABR test in the VS group showed that the latency of wave V and I-V interval were significantly prolonged compared to the HFS group ( t=8.36, P<0.001; t=4.61, P<0.001).In VS group, all tumors were totally removed with preserved facial nerve function (House-Brackmann grade Ⅰ-Ⅱ). The serviceable hearing preservation rate was 63.3%. In the HFS group, the initial CNAP waveforms were triphasic and biphasic, with N1 wave latency of (4.32±0.37) ms and amplitude of 25.20 [15.63, 35.40]μV. The distribution of CNAP waveforms before tumor resection in the VS group was the same as that in the HFS group, and which in the hearing preservation group after surgery was also the same. Compared with the HFS group, the latency of N1 wave was prolonged ( t=2.670, P=0.011; t=4.584, P<0.001), and the amplitude of N1 wavein the VS group before tumor resection was lower ( Z=-3.001, P=0.003). The amplitude of N1 wave in the hearing preservation group after surgery was 20.20 [6.23, 40.90] μV,which was significantly higher than that before tumor resection ( Z=-2.133, P=0.033), but there was no statistically significant difference compared to the HFS group ( Z=-0.495, P=0.621). Conclusions:The reference range of CNAP in normal hearing population can be preliminarily obtained by the analysis of CNAP in MVD surgery. The latency of N1 wave in VS patients is prolonged and the amplitude of N1 wave is decreased due to tumor compression. The CNAP waveform combined with the change of N1 wave amplitude can provide reference for intraoperative mapping of the cochlear nerve and prediction of postoperative hearing preservation.
