Hinojosa R, Green J D, Marion M S
Department of Surgery, University of Chicago, Illinois.
Am J Otol. 1991;12 Suppl:3-7; discussion 18-21.
Ossification of the perilymphatic spaces of the inner ear is frequently found in patients with profound deafness who may be candidates for cochlear implantation. The ossification may be a hindrance in electrode insertion and has previously been considered a relative contraindication to implantation. The quantity of peripheral auditory elements remaining in a series of patients with labyrinthitis ossificans has not been reviewed. We performed a histopathologic study of 16 temporal bones with partial cochlear ossification of multiple etiologies. The organ of Corti and spiral ganglion were graphically reconstructed. The degree of obstruction was estimated for each millimeter of the scala tympani and scala vestibuli. A quantitative evaluation of the sensorineural elements of the inner ear (spiral ganglion cells, inner and outer hair cells, and peripheral auditory axons) was performed. The results were compared with 16 control patients with normal hearing and no evidence of cochlear ossification. Our results show that the greatest amount of damage is found in the organ of Corti with preservation of a significant number of spiral ganglion cells in most cases. A wide range of ganglion cells (6,310 to 28,196) was found in patients with labyrinthitis ossificans with the mean number of ganglion cells being 17,152. A profound sensorineural hearing loss was noted in all patients except one. Meningogenic labyrinthitis and otosclerosis were associated with the greatest loss of ganglion cells. The location of ossification could be correlated with the region showing loss of the organ of Corti. In the majority of patients, the location of ossification and fibrosis could not be correlated with the region of the spiral ganglion showing loss of ganglion cells. The implications of these findings for cochlear implantation is discussed.
内耳外淋巴间隙骨化在极重度耳聋患者中较为常见，这些患者可能是人工耳蜗植入的候选者。这种骨化可能会阻碍电极插入，以前被认为是植入的相对禁忌证。关于一系列骨化性迷路炎患者中残留的外周听觉元件数量尚未有相关综述。我们对16例因多种病因导致部分耳蜗骨化的颞骨进行了组织病理学研究。对柯蒂器和螺旋神经节进行了图形重建。对鼓阶和前庭阶的每毫米梗阻程度进行了评估。对内耳的感觉神经元件（螺旋神经节细胞、内毛细胞和外毛细胞以及外周听觉轴突）进行了定量评估。将结果与16例听力正常且无耳蜗骨化证据的对照患者进行了比较。我们的结果表明，大多数情况下，柯蒂器受损最严重，但仍保留了大量螺旋神经节细胞。骨化性迷路炎患者的神经节细胞数量范围很广（6310至28196个），神经节细胞的平均数量为17152个。除1例患者外，所有患者均有极重度感音神经性听力损失。脑膜炎性迷路炎和耳硬化症与神经节细胞的最大损失有关。骨化的位置与柯蒂器显示缺失的区域相关。在大多数患者中，骨化和纤维化的位置与螺旋神经节显示神经节细胞缺失的区域无关。本文讨论了这些发现对人工耳蜗植入的意义。
