Lamm H, Lehnhardt E, Lamm K
Acta Otolaryngol. 1984 Nov-Dec;98(5-6):454-61. doi: 10.3109/00016488409107586.
The round window membrane of the inner ear of the guinea pig was perforated under Ketanest anaesthesia. A very rapid and almost total loss of cochlear microphonics, auditory nerve action potential and brain-stem response developed. Replacement of the perilymph with Ringer's solution and surgical closure of the membrane damage had no effect on auditory nerve action potential or brain-stem response. Further decline in the amplitude of cochlear microphonics was halted, however. When perfusion of the round window membrane was carried out whilst the bulla was full with Ringer's solution, no essential decline was seen in the amplitudes of microphonics and auditory nerve action. Only brain-stem response was reduced--temporarily by 40% of the original amplitudinal level--but this showed subsequent recovery. Preservation of cochlear microphonics and auditory nerve action after perforation in Ringer's solution, i.e. excluding air, indicates that air entering the scala tympani is the cause of the sudden hearing loss after round window perforation. Using a simple physical model, an attempt is made to demonstrate this process. The anatomic connections between the round window, cochlear aqueduct and scala tympani are discussed, as are the different ways in which the round window membrane can be perforated.
豚鼠内耳的圆窗膜在氯胺酮麻醉下被穿孔。耳蜗微音器电位、听神经动作电位和脑干反应迅速且几乎完全丧失。用林格氏液替代外淋巴并对膜损伤进行手术封闭，对听神经动作电位或脑干反应没有影响。然而，耳蜗微音器电位的幅度进一步下降停止了。当在鼓泡充满林格氏液时对圆窗膜进行灌注，微音器电位和听神经动作的幅度没有明显下降。只有脑干反应降低了——暂时降低到原始幅度水平的40%——但随后显示出恢复。在林格氏液中穿孔后耳蜗微音器电位和听神经动作得以保留，即排除空气，这表明进入鼓阶的空气是圆窗穿孔后突然听力丧失的原因。使用一个简单的物理模型，试图演示这个过程。讨论了圆窗、蜗水管和鼓阶之间的解剖连接，以及圆窗膜穿孔的不同方式。
