Banakis Hartl Renee M, Mattingly Jameson K, Greene Nathaniel T, Farrell Nyssa F, Gubbels Samuel P, Tollin Daniel J
*Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado †Auditory Protection and Performance Division, U.S. Army Aeromedical Research Lab, Fort Rucker, Alabama ‡Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado.
Otol Neurotol. 2017 Aug;38(7):938-947. doi: 10.1097/MAO.0000000000001474.
Drilling on the incus produces intracochlear pressure changes comparable to pressures created by high-intensity acoustic stimuli.
New-onset sensorineural hearing loss (SNHL) following mastoid surgery can occur secondary to inadvertent drilling on the ossicular chain. To investigate this, we test the hypothesis that high sound pressure levels are generated when a high-speed drill contacts the incus.
Human cadaveric heads underwent mastoidectomy, and fiber-optic sensors were placed in scala tympani and vestibuli to measure intracochlear pressures (PIC). Stapes velocities (Vstap) were measured using single-axis laser Doppler vibrometry. PIC and Vstap were measured while drilling on the incus. Four-millimeter diamond and cutting burrs were used at drill speeds of 20k, 50k, and 80k Hz.
No differences in peak equivalent ear canal noise exposures (134-165 dB SPL) were seen between drill speeds or burr types. Root-mean-square PIC amplitude calculated in third-octave bandwidths around 0.5, 1, 2, 4, and 8 kHz revealed equivalent ear canal (EAC) pressures up to 110 to 112 dB SPL. A statistically significant trend toward increasing noise exposure with decreasing drill speed was seen. No significant differences were noted between burr types. Calculations of equivalent EAC pressure from Vstap were significantly higher at 101 to 116 dB SPL.
Our results suggest that incidental drilling on the ossicular chain can generate PIC comparable to high-intensity acoustic stimulation. Drill speed, but not burr type, significantly affected the magnitude of PIC. Inadvertent drilling on the ossicular chain produces intense cochlear stimulation that could cause SNHL.
在砧骨上钻孔产生的耳蜗内压力变化与高强度声刺激所产生的压力相当。
乳突手术后新发感音神经性听力损失（SNHL）可能继发于中耳听骨链的意外钻孔。为了对此进行研究，我们检验了以下假设：高速钻头接触砧骨时会产生高声压级。
对人类尸体头部进行乳突切除术，并将光纤传感器置于鼓阶和前庭阶以测量耳蜗内压力（PIC）。使用单轴激光多普勒振动测量法测量镫骨速度（Vstap）。在对砧骨进行钻孔时测量PIC和Vstap。使用4毫米金刚石钻头和切割钻，钻孔速度分别为20k、50k和80k赫兹。
在不同钻孔速度或钻头类型之间，峰值等效耳道噪声暴露（134 - 165 dB SPL）没有差异。在0.5、1、2、4和8 kHz附近的三分之一倍频程带宽中计算得出的均方根PIC振幅显示等效耳道（EAC）压力高达110至112 dB SPL。观察到随着钻孔速度降低，噪声暴露有显著增加的趋势。不同钻头类型之间未发现显著差异。根据Vstap计算得出的等效EAC压力在101至116 dB SPL时显著更高。
我们的结果表明，中耳听骨链的意外钻孔可产生与高强度声刺激相当的PIC。钻孔速度而非钻头类型显著影响PIC的大小。中耳听骨链的意外钻孔会产生强烈的耳蜗刺激，可能导致SNHL。
