Jiang Dan, Bibas Athanasios, Santuli Carlo, Donnelly Neil, Jeronimidis George, O'Connor Alec Fitzgerald
Department of Otolaryngology, Head and Neck Surgery, Auditory Implantation Centre, Guy's and St. Thomas Hospitals, London, United Kingdom.
Laryngoscope. 2007 Jun;117(6):1040-5. doi: 10.1097/MLG.0b013e3180459a10.
Inadvertent drilling on the ossicular chain is one of the causes of sensorineural hearing loss (HL) that may follow tympanomastoid surgery. A high-frequency HL is most frequently observed. It is speculated that the HL is a result of vibration of the ossicular chain resembling acoustic noise trauma. It is generally considered that using a large cutting burr is more likely to cause damage than a small diamond burr.
The aim was to investigate the equivalent noise level and its frequency characteristics generated by drilling onto the short process of the incus in fresh human temporal bones.
Five fresh cadaveric temporal bones were used. Stapes displacement was measured using laser Doppler vibrometry during short drilling episodes. Diamond and cutting burrs of different diameters were used. The effect of the drilling on stapes footplate displacement was compared with that generated by an acoustic signal. The equivalent noise level (dB sound pressure level equivalent [SPL eq]) was thus calculated.
The equivalent noise levels generated ranged from 93 to 125 dB SPL eq. For a 1-mm cutting burr, the highest equivalent noise level was 108 dB SPL eq, whereas a 2.3-mm cutting burr produced a maximal level of 125 dB SPL eq. Diamond burrs generated less noise than their cutting counterparts, with a 2.3-mm diamond burr producing a highest equivalent noise level of 102 dB SPL eq. The energy of the noise increased at the higher end of the frequency spectrum, with a 2.3-mm cutting burr producing a noise level of 105 dB SPL eq at 1 kHz and 125 dB SPL eq at 8 kHz. In contrast, the same sized diamond burr produced 96 dB SPL eq at 1 kHz and 99 dB at 8 kHz.
This study suggests that drilling on the ossicular chain can produce vibratory force that is analogous with noise levels known to produce acoustic trauma. For the same type of burr, the larger the diameter, the greater the vibratory force, and for the same size of burr, the cutting burr creates more vibratory force than the diamond burr. The cutting burr produces greater high-frequency than lower-frequency vibratory energy.
在鼓室乳突手术中，不慎钻到听骨链是感音神经性听力损失（HL）的原因之一。高频HL最为常见。据推测，这种HL是听骨链振动类似于声噪声创伤的结果。一般认为，使用大的切割钻比小的金刚石钻更易造成损伤。
旨在研究在新鲜人颞骨砧骨短突上钻孔产生的等效噪声水平及其频率特性。
使用五具新鲜尸体的颞骨。在短时间钻孔过程中，使用激光多普勒振动测量法测量镫骨位移。使用不同直径的金刚石钻和切割钻。将钻孔对镫骨足板位移的影响与声信号产生的影响进行比较。由此计算等效噪声水平（dB声压级等效值[SPL eq]）。
产生的等效噪声水平范围为93至125 dB SPL eq。对于1毫米的切割钻，最高等效噪声水平为108 dB SPL eq，而2.3毫米的切割钻产生的最大水平为125 dB SPL eq。金刚石钻产生的噪声比切割钻少，2.3毫米的金刚石钻产生的最高等效噪声水平为102 dB SPL eq。噪声能量在频谱的高端增加，2.3毫米的切割钻在1 kHz时产生的噪声水平为105 dB SPL eq，在8 kHz时为125 dB SPL eq。相比之下，相同尺寸的金刚石钻在1 kHz时产生96 dB SPL eq，在8 kHz时产生99 dB。
本研究表明，在听骨链上钻孔可产生与已知会导致声创伤的噪声水平类似的振动力。对于同一类型的钻，直径越大，振动力越大；对于相同尺寸的钻，切割钻比金刚石钻产生的振动力更大。切割钻产生的高频振动能量比低频振动能量更大。
