Experimental study on transplantation of allograft tympanic membrane (1)

Abstract

Since 1981, allograft tympanoplasties were started in our clinic and the allograft materials were offerd for use by courtesy of the “Hyogo Ear Bank”.
Allograft tympanic membrane for clinical use was treated in 4% buffered formaldehyde for a week, deepithelized, rinse with a plenty amount of saline, gas sterilized, prefrozen to -70°C and was then freeze-dried for 5 days.
As the first step, using the human and cat tympanic membrane, histologic change of allograft tympanic membrane was studied with microscopic and SEM observation in different stage of above mentioned treatment. The following results were obtained. 1. The more the preparation proceeds, the more the middle layer of tympanic membrane became loose and thin. 2. The same is true that the gaps between each of 3 layers (epithelial, middle and mucosal) were widened as the treatment proceeds. These results suggest that deepithelization can be more easily done after 4% buffered formaldehyde treatment, and also the loose connective layer of the allograft tympanic membrane can easily allow the host's fibroblast and blood vessels to growing in.