Retrospective study of intra-operative testing with the Nucleus CI24M cochlear implant and use of the back-up device.

The combined use of integrity testing (IT) and impedance telemetry (ImTe) intra-operatively is evaluated. One hundred and fifty children implanted with the Nucleus device were studied. In 81% of patients, normal results were obtained on all electrodes from both ImTe and IT. In seven cases where the back-up device was used, the intra-operative analysis of the device and subsequent postoperative quality assurance testing did not always correlate. In conclusion, intra-operatively, only ImTe is needed to verify the function of the implant if all impedance values are normal. However, in the case of abnormal ImTe results, additional IT data provide valuable assistance with the decision of whether to leave the implant in place or to use the backup device.