[Use of intraoperative round window electrocochleography for assessment of cochlear implantation safety].

OBJECTIVE: To objectively evaluate whether cochlear implantation surgery made damage to cochlear basal membrane or not through analyzing the change of the threshold of cochlear microphonic (CM) of round window electrocochleography before and after inserting electrode during cochlear implantation surgery. METHOD: Round window electrocochleography was performed on 40 cases with profound sensorineural deafness under general anesthesia in the standard operating room in order to analyze the change of the threshold of cochlear microphonic (CM) of round window electrocochleography before and after inserting electrode during cochlear implantation surgery. RESULT: Among the 40 cases, thresholds of cochlear microphonic (CM) before and after inserting electrode during cochlear implantation surgery were similar in 39 cases. The thresholds of cochlear microphonic (CM) after inserting electrode decreased about 5 dB at certain frequency. The thresholds of cochlear microphonic (CM) after inserting electrode increased 20-50 dB in only one case. There was a sense of resistance in implanting the electrodes in this patient. CONCLUSION: Use of round window electrocochleography may objectively evaluate whether cochlear implantation surgery make damage to cochlear basal membrane or not.