Conclusion: Noise levels sufficient to cause sensorineural hearing loss can be measured when electrical drills and suction are used during otological surgery, particularly if a running burr touches the endosteal membrane of the otic capsule. Our noise measurements confirm the theory that 'soft surgery' should be employed during otological surgery, with focus on reduction of noise exposure.
Objective: To investigate noise levels generated by otological electrical drills and suction.
Methods: Airborne noise levels generated by different drills and suction tips of different diameters were evaluated in 12 fresh isolated human temporal bones by means of an ER7C probe microphone system.
Results: Noise levels ranged from 120 to 122 dB SPL during drilling in cortical bone and from 117 to 121 dB SPL during drilling in the mastoid cavity. There was no statistically significant difference between cutting and diamond burrs (p > 0.05). Noise levels during cochleostomy ranged from 116 to 131 dB SPL. Noise levels recorded in the round window exceeded 130 dB SPL when the endosteal membrane was touched by the burr. Noise levels generated by various types of suctions ranged from 100 to 129 dB SPL and a positive significant relation was found between noise and increased luminal diameter of the suction tip up to a diameter of 2 mm.