Eight-nerve electrophysiology after electrocautery in cochlear implant patients

Abstract

Problem: To date, there have been over 50,000 cochlear implant recipients; however, there have been no data in the literature regarding safety or complications from the use of monopolar electrocautery in patients with cochlear implants. We address the use of monopolar electrocautery in patients with cochlear implants and the effects of the cautery on the function of the implant and the primary afferent neurons with which this auditory prosthesis interfaces. Methods: The electrically evoked whole nerve action potential of the auditory nerve was measured using neural response telemetry obtained using typical stimulation parameters. Recording electrodes were 2 electrodes away in the apical direction. Results: Neural response telemetry demonstrated auditory nerve activity via electrical stimulation and confirmed proper functioning of the cochlear implant before and after monopolar electrocautery use. Electrical compound action potential (ECAP) thresholds obtained following exposure to monopolar electrocautery were within 5 current level steps of the initial results. Increases in stimulus level resulted in expected increase in response amplitude and response morphology remained consistent. Behavioral reports indicated sound perception as expected for these types of measures. Finally, electrode voltage impedances were within the normal range, within compliance, and similar between sessions. Conclusion: Neural response telemetry demonstrated a fully functional cochlear implant after being exposed to monopolar electrocautery. We feel that the use of monopolar electrocautery at a site distant from the cochlear implant poses little risk to the proper functioning of the cochlear implant. Significance: To date, there is an absence in the literature regarding the use of electrocautery, either monopolar or bipolar in patients with cochlear implants. Given the current practice of implanting young children, the likelihood of those patients needing future surgeries is very high. It is important to establish the safe parameters for the use of electrocautery for these and all patients who have been implanted. Support: None reported.