两种听觉监护在听神经瘤术中的联合应用及评价

目的　探讨听神经瘤手术中听觉监护的意义。比较听性脑干反应（ABR）和蜗神经动作电位（cochlear nerve action potential，CNAP）在听觉监护应用中的价值。方法　回顾性分析我中心12例保留听力手术的听神经瘤患者资料及术中情况，患者术前均有实用听力（AAO-HNS分级A级、B级），可引出ABR波形，V波分化可，所有手术均采取乙状窦后径路摘除肿瘤。所有患者均全程ABR监护，术中打开脑膜后联合监测CNAP。结果　手术过程中所有患者ABR波形较术前基线均有不同程度的变化，可记录到V波潜伏期均较基线延长（0.68±0.41）ms。CNAP波幅个体差异性较大，可记录到的P1潜伏期均较基线延长（0.25±0.16）ms。12例中有8例（66.7%）患者术后保留可用听力；另外4例（33.3%）术后达不到可用听力，此4例患者ABR表现为3例V波消失，1例V波潜伏期延长。CNAP表现为2例CNAP的P1消失，2例P1延长。电钻钻磨造成的震动和噪声、手术时神经被牵拉或热损伤后等急性损伤后ABR和CNAP波幅均出现短时间急剧下降，手术暂停5 min后，部分患者波幅可在一定程度恢复。结论　听神经瘤手术中ABR和CNAP对于听觉监护均有一定意义。ABR波形稳定可靠，但叠加时间相对较长；CNAP叠加快速，可提升监测灵敏度，但波形变异度较大。电钻钻磨造成的震动和噪声、操作过程中对神经组织的牵拉以及热损伤均被及时监控，两者联合应用可提升听神经瘤手术的听觉功能保留率。

Combined application and evaluation of two types of auditory monitoring in acoustic neuroma surgery

OBJECTIVE To explore the significance of intraoperative auditory monitoring(IAMA) in surgery of acoustic neuroma and to compare the value of auditory brainstem response(ABR) and cochlear nerve action potential(CNAP) in auditory monitoring.METHODS Retrospective analysis of 12 cases of acoustic neuroma from January 2016 to December 2016 was performed.All patients have a practical hearing(AAO-HNS,grade class a,b),the ABR waveform can be elicited,wave v differentiation,All tumors were removed via posterior sigmoid sinus approach.RESULTS ABR waveform of all patients were prolonged with different degrees of change(0.68±0.41) ms compared with the preoperative data.Amplitude of CNAP diverse in different individuals,with an average prolong compared to the data before operation(0.25±0.16) ms.In all 12 cases,8 (66.7％) patients remained usable hearing after the operation,4 cases(33.3％) failed to have a usable hearing.Among these 4 patients,3 showed disappearance of wave v,1 patient showed wave v latency prolong in the ABR,meanwhile,2 patients showed P1 dissapear,2 patients showed P1 latency prolong in CNAP.The intraoperative auditory monitoring could play a role in preventing the hearing damage in the procedure.Drilling,noise,surgical nerve stretch or thermal injury may cause the hearing damage.A 5 minutes pause could get some degree of regain,with the amplitude rise again.CONCLUSION A combination use of the ABR and CNAP monitoring has a certain significance in surgery of acoustic neuroma.ABR waveform is stable and reliable,but costs longer time;CNAP stack quickly and improve monitoring sensitivity,but waveform varies.Vibration and noise caused by drilling,nerve stretch during operation and heat damage can be monitored timely.Combined use of ABR and CNAP monitoring can enhance the auditory preservation rate during acoustic neuroma surgery.