Does monopolar cautery use adversely affect an existing cochlear implant?
Background: Since the inception of cochlear implantation, monopolar cautery use has been contraindicated in patients with a cochlear implant in place. Risk of injury to the patient through abnormal spread of electrical current or risk of electrical damage to the cochlear implant device are the principal reasons. In the U.S., the three manufacturers of FDA-approved cochlear implant devices recommend against the concurrent use of monopolar electrocautery in patients with a cochlear implant.
Study design: Sixteen cochlear implant devices from the three manufacturers of FDA-approved cochlear implant devices were implanted into two unembalmed fresh cadavers. Monopolar electrocautery was applied at a location on the tongue and separately on the abdomen. The cochlear implant devices were monitored for changes in electrode impedance and internal electrical integrity before, during and after cautery. A thermocouple was used to measure perilymph temperature adjacent to the electrode array within the cochlea. Each cochlear implant device was returned to the manufacturer and underwent the respective evaluation protocol for an explanted cochlear implant device.
Synopsis: At settings of 10 W and 50 W, monopolar electrocautery was performed for periods of one, five, 10 and 30 minutes at locations on the tongue and the abdominal skin and subcutaneous soft tissue. No temperature change was measured within the cochlea for four different cochlear implant devices. No changes in cochlear implant electrode impedance or device integrity were measured. Comprehensive device analysis by the manufacturers did not detect any evidence of damage.
Bottom line: The study did not find evidence of thermal change within the cochlea or damage to the cochlear implant devices during the period of monopolar electrocautery use. The explanted cochlear implants did not show evidence of damage. Because this was a cadaver study, the authors were not able to assess whether there was other evidence of altered spread of electrical current due to the presence of the cochlear implant and whether living tissue would respond differently than fresh, unembalmed cadaver tissue.
Citation: Jeyakumar A, Wilson M, Sorrel JE, et al. Monopolar cautery and adverse effect on cochlear implants. JAMA Otolaryngol Head Neck Surg. 2013;139:694-697.
—Reviewed by George T. Hashisaki, MD