Drill-induced noise level during cochleostomy.

CONCLUSIONS

Noise induced by drilling during cochleostomy is of high level and can cause acoustic trauma to the inner ear, particularly after the membranous labyrinth has been exposed. Our method utilizes non-invasive noise measurement and the equipment that is connected to the operative area can be sterilized, thus it can be applied to intraoperative recordings.

OBJECTIVES

To investigate the noise level generated by otological electrical drills during the cochleostomy procedure and to further explore the feasibility of noise monitoring in vivo.

METHODS

Acoustic measurements during drilling on the promontory of cochleae were carried out on 16 human cadavers (19 ears) using an ER7C probe microphone system.

RESULTS

The peak noise level generated during cochleostomy differed obviously from specimen to specimen and ranged from 85.9 to 131.5 dB SPL. We found three cases in which the peak noise level exceeded 130 dB SPL when the running burr touched the endosteal membrane.