Eze Nneka, Jiang Dan, Fitzgerald O'Connor Alec
Hearing Implant Centre, St Thomas' Hospital , London , UK.
Acta Otolaryngol. 2014 Nov;134(11):1109-13. doi: 10.3109/00016489.2014.914245.
Drilling a cochleostomy exposes the cochlea to acoustic and mechanical trauma, particularly during the final stage when the running burr is in contact with an intact membranous labyrinth that is then breached. To minimize cochlear damage we recommend avoidance of prolonged contact of the running burr with the membranous labyrinth. The promontory should be drilled until a thin eggshell of bone remains that can be removed with microinstruments, thus allowing the atraumatic opening of the membranous labyrinth with a sharp instrument.
To determine the energy transmitted to the inner ear while drilling a cochleostomy.
Eight human cadaveric temporal bones were used. Stapes velocity as measured with the laser Doppler vibrometer was used as a reflection of energy input to the cochlea. Measurements were taken during the different stages of cochleostomy formation using a 1 mm diamond burr: drill on promontory, edge of the fenestration, blue-lined fenestration, membranous labyrinth and through the membranous labyrinth.
Drilling the promontory in preparation for the cochleostomy causes minimal energy transmission into the cochlea. There is significant and marked cochlea energy transfer when the running burr touches the membranous labyrinth and enters the scala tympani of a magnitude similar to touching the incus.
钻制人工耳蜗开窗术会使耳蜗暴露于声学和机械性创伤中，尤其是在最后阶段，即旋转的钻针接触到完整的膜迷路然后将其穿破时。为了将耳蜗损伤降至最低，我们建议避免旋转的钻针与膜迷路长时间接触。应该对岬部进行钻孔，直到仅剩下一层薄骨壳，可用微型器械将其去除，从而能用锐利器械无创伤地打开膜迷路。
确定钻制人工耳蜗开窗术时传递至内耳的能量。
使用了8个尸体颞骨。用激光多普勒振动计测量的镫骨速度被用作输入到耳蜗的能量的反映。在使用1毫米金刚石钻针进行人工耳蜗开窗术形成的不同阶段进行测量：在岬部钻孔、开窗边缘、蓝线标记的开窗、膜迷路以及穿过膜迷路。
为人工耳蜗开窗术做准备而在岬部钻孔时，传入耳蜗的能量最小。当旋转的钻针接触膜迷路并进入鼓阶时，会有显著且明显的耳蜗能量传递，其程度与接触砧骨时相似。
