STUDIES ON THE POSTMORTEM CHANGES OF THE HUMAN INNER EAR (PARS AUDITIVA) BY DAITO'S INNER EAR IRRIGATING FIXATION METHOD

Abstract

A study was made on postmortem changes in the human inner ear by Daito's inner ear irrigating fixation method. The materials used in the present study were 50 ears isolated from 36 autopsy cases which were presented by Tokyo Medical Examiner's Office during the winter season. These materials were divided into 4 groups according to the interval between the death and the fixation of each cases.The results were as follows:1. Group 1: Five to eight hours after death (15 ears from 9 cases) The specimen showed no marked change in the stria vascularis. The outer hair cells were atrophic, slender, and contained pyknotic nuclei or voluminous and contained paler and round nuclei. The former type of the cells had a resemblance in shape to those observed in the specimen fixed by intravital method.The cytoplasm of the supporting cells appeared pale and contained fine granules. Furthermore, slight tigrolysis was observed in the spiral ganglion cells without any distinct histological change in their nuclei.2. Group 2: Nine to fourteen hours after death (11 ears from 11 cases) Slight damage was found in the stria vascularis. The outer hair cells became spherical or flask-shaped. Their nuclei were round in shape. The nuclei of the spiral ganglion cells showed no marked change, while the cytoplasm became atrophic and dark in appearance. Inside the ganglion cells, Nissl's bodies were yet clearly visible. Little change was noticed in the supporting cells in this stage.3. Group 3: Nineteen to twentyfour hours after death (20 ears from 12 cases) The stria vascularis had undergone dissolution. The outer hair cells became spherical in shape and lost their differentiation, while the inner hair cells tended to deteriolate in this stage. Most of the spiral ganglion cells had pyknotic nuclei and uneven cytoplasm. The bounderies of the supporting cells appeared slightly indistinct.4. Groups 4: Fortyeight hours after death (4 ears from 4 cases) The endorgan of Corti lost its normal appearance except some supporting cells which were identified even in this stage, viz.Claudius's cells, some of Hensen's cells and some of pillar cells. The endolymphatic space was filled with debris of degenerated cells and plasma cells.No genuine neuroepithelial degeneration (picture of Collapse) was observed in all specimens examined.