A comparison between neural response telemetry via cochleostomy or the round window approach in cochlear implantation

There are two techniques for cochlear implant (CI) electrode placement: cochleostomy and the round window (RW) approach. Objective: This study aims to compare neural response telemetry (NRT) results immediately after surgery to check for possible differences on auditory nerve stimulation between these two techniques. Materials and Methods: This is a prospective cross-sectional study. Twenty-three patients were enrolled. Six patients underwent surgery by cochleostomy and 17 had it through the RW approach. Results: Mean charge units (MCU) for high frequency sounds: patients submitted to the RW approach had a mean value of 190.4 (±29.2) while cochleostomy patients averaged 187.8 (±32.7); p = 0.71. MCU for mid frequency sounds: patients submitted to the RW approach had a mean value of 192.5 (±22) while cochleostomy patients averaged 178.5 (±18.5); p = 0.23. MCU for low frequency sounds: patients submitted to the RW approach had a mean value of 183.3 (±25) while cochleostomy patients averaged 163.8 (±19.3); p = 0.19. Conclusion: This study showed no differences in the action potential of the distal portion of the auditory nerve in patients with multichannel cochlear implants submitted to surgery by cochleostomy or through the RW approach, using the implant itself to generate stimuli and record responses. Both techniques equally stimulate the cochlear nerve. Therefore, the choice of approach can be made based on the surgeon's own preference and experience.