Cochlear Implants and Electrocautery: A Live Animal Model

The use of monopolar cautery is regarded as a contraindication in cochlear implant (CI) recipients, despite a large amount of contradicting data. The objectives are as follows: (1) Evaluate the effects of high-powered electrocautery on CI devices. (2) Record any high-powered electrocautery induced temperature changes.

After IACUC approval, 12 manufacturer-donated CIs were implanted in two anesthetized pigs. All devices underwent pre-study integrity checks; six had onsite impedance testing, while six received post-cautery analysis. Fifty watts coagulation was applied for 20 min at sites 1-15 cm from the CI. Bluetooth thermometers monitored three sites of temperatures. Devices were explanted for analysis. Stata 17.0 was used for statistical analysis. A p-value < 0.05 was considered statistically significant. Outcome measurements were as follows: (1) Changes in the temperature. (2) Changes to the implanted CIs during electrocautery. (3) CI integrity analysis following electrocautery.

The mean temperatures at the three sites (a*, b*, c*) was 32.9°C-38.8°C. Maximum absolute temperature changes averaged 4.1°C (95% CI: 1.4-6.8) for scalp measurements and 2.9°C (95% CI: 1.0-4.9) for round window measurements. Neither time (p = 0.09) nor distance (p = 0.64) generated significant scalp temperature changes. Devices were stratified by proximity. Mean maximum temperature changes showed a gradient by distance. Differences in device proximity were not statistically significant. Postimplantation device analysis was performed on six devices, and all passed the manufacturer in-depth device analysis.

This controlled experimental evidence, demonstrating 100% device integrity across all tested conditions, challenges current manufacturer contraindications and supports evidence-based guideline revision.

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