[Mastoid pneumatization after blocking the aeration route through the eustachian tube]

In the mastoid air cell system, air has been thought to be supplied only through the eustachian tube and tympanic cavity to the cells, and to be absorbed continuously in one direction through the lining mucosa of the mastoid air cells. In the ear with a blocked air supply route to the mastoid air cell system, gas in the blocked mastoid air cells has been thought to be absorbed and to be replaced by exudate. Recently, several observations have supported the existence of gas exchange not only through the eustachian tube but through the lining mucosa in the mastoid. To clarify gas exchange in mastoid air cells, tympanic cavities of the infant piglet, the tympanic bullae of which is similar to the human mastoid air cell system, were filled with jellied adhesive, an alpha-cyanoacrylate monomer, to block the aeration route to the air cells, and tympanic bullae were examined histopathologically. Group 1: Injection of adhesive into the tympanic cavity 1 month after birth following glycerin injection at 1 week after birth. Group 2: Injection of adhesive 1 month after birth without any prior injection into the tympanic cavity. Group 3: Injection of adhesive 3 months after birth without prior injection. In group 1, remarkable inflammation was subsequently observed in the tympanic bullae, development of the air cell system was markedly inhibited and very few air cells remained intact. In groups 2 and 3, however, inflammatory reactions were relatively mild normal air cells remained on the periphery and development of the air cell system was not interrupted.(ABSTRACT TRUNCATED AT 250 WORDS)