INTRAOPERATIVE AUDITORY MONITORING IN ACOUSTIC NEUROMA SURGERY

Intraoperative auditory monitoring is a useful adjunct that is current ly evolving, Near-field monitoring techniques such as electrocochleogr aphy and direct eighth nerve compound action potential are being used more frequently, The use of these two techniques is compared in 26 pat ients undergoing hearing preservation acoustic neuroma resection, Over all, 9 (35%) of the 26 patients had their hearing preserved, Three (23 %) of the 13 with electrocochleography monitoring and 6 (46%) of the 1 3 with direct compound action potential monitoring had hearing preserv ed after surgery, Although there was a suggestion of improved results with direct compound action potential monitoring, the results were not statistically different, It was noted that lack of electrical respons e at the completion of the procedure (regardless of monitoring techniq ue) was correlated with poor postoperative hearing, whereas the presen ce of a waveform at termination in no way predicted satisfactory posto perative hearing, The two techniques and their advantages and disadvan tages are discussed.