Preliminary Study On The Application Of ABR Combined With Electrocochleography Monitoring In Acoustic Neuroma

Objective To explore the significance of the combined use of ABR and electrocochleography intraoperative monitoring of acoustic neuroma.Methods 6 patients who underwent sigmoid sinus approach and underwent acoustic neuroma resection under ABR and electrocochleography were combined to analyze the preoperative and postoperative findings combined with intraoperative hearing monitoring.The preoperative and postoperative hearing results of 11 patients who were not undergoing intraoperative monitoring were compared.Hearing classes was evaluated by the American Academy of Otorhinolaryngology Head and Neck Surgery.Results Among the 6 patients who underwent intraoperative monitoring,preoperative vestibular-evoked myogenic potential(VEMPs)showed that 5cases tumors originated from the superior vestibular nerve,1 case originated from the inferior vestibular nerve;2 patients with preoperative I,III,V differentiations were good,preoperative hearing class A,2 patients only had V wave differentiation before operation,preoperative hearing class B,2 patients with I and V wave differentiation,preoperative hearing class C.Preoperative electrocochleography compound action potential(CAP)was present in 6patients.During the whole operation,2 patients had no significant prolongation of V-wave latency,no significant changes in waveform,CAP repeatability well,and postoperative hearing maintenance preoperative hearing level(1 in class A,1 in class C),When the dura mater was opened,the ABR and CAP waveforms disappeared in 1 patient.The waveform was restored after the surgery was suspended and the dexamethasone was infused.The postoperative hearing was class B.In one patient,the V-wave amplitude decreased significantly when the tumor was separated from the blood vessel,but the CAP persisted and the postoperative hearing was class C.In 2 patients,the V wave and CAP disappeared during the tumor resection and electrocoagulation,and the failed to recovery until the end of the operation,postoperative hearing class D.Tumor removal process,electrocoagulation in the operation area,and tumor and blood vessel separation will change the monitoring waveform.In comparison with 11 patients without intraoperative monitoring,there were no significant differences in tumor size and preoperative hearing between the two groups(P>0.05).There was a statistically significant difference in hearing retention between the two groups(P<0.01).Conclusion ABR combined with electrocochleography surgery has positive significance for postoperative hearing prevention,and can timely feedback the sensitive operation of hearing impairment during surgery.