内外リンパシャントと内リンパ水腫 動物実験と人側頭骨標本症例

Abstract

Endolymph-perilymph shunts were produced in 20 guinea pigs with endolymphatic hydrops induced by the silver nitrate method. The shunt was created between the scala media and the scala tympani through the basilar membrane in the basal turn of the cochlea. At various intervals (3 hours-27 days), animals were sacrificed and prepared for pathological examination. In 10 of the 20 animals the shunt was visible, varying from a small fissure to 200 microns in width. In the other 10 animals the shunt had probably healed over, because fracture lines were often observed. In those examined 3 hours to 3 days after operation, there was slight membranous collapse. After 7 to 27 days however, the animals showed hydrops even if the shunt was still patent. Severe degenerative changes of Corti's organ and severe atrophy of the stria vascularis were observed adjacent to the shunt area. The temporal bone of a patient with otosclerosis and Meniere's disease was also studied. Otosclerosis had invaded the lateral wall of the cochlea inducing atrophy of the spiral ligament, stria vascularis and basilar membrane to create a natural endolymph-perilymph shunt between the scala media and the scala tympani. This structure resembled the shunt produced experimentally in guinea pigs. The patient had suffered from vertigo which later disappeared although hearing loss was severe. The shunt may have worked as a pressure-releasing fistula.