PNEUMATIZATION OF TYMPANIC TYMPANIC BULLA AFTER BLOCKAGE OF THE VENTILATION ROUTE THROUGH THE EUSTACHIAN-TUBE IN THE PIG

To examine whether gas exchange occurs in the middle ear air cell syst em independent of the: eustachian tube (ET), we occluded the middle ea r clefts of piglets, whose tympanic bullae closely resemble the human mastoid air cell system, and investigated subsequent changes in the ai r cell system. We anticipated that pneumatization and development of t he air cell system would continue if gas were exchanged through the mu cosa lining the air cell system. if, on the other hand, mastoid air ce lls depend on the ET, mastoid development would be impaired or arreste d. In noninflamed ears, pneumatization was maintained, and development of the air cell system continued after the middle ear cleft had been occluded with an acrylate adhesive and the bullar air cell system was thus excluded from any communication with the ET. These results indica te that the normal middle ear air cell system has the capacity to perf orm gas exchange independently of the ET, with gas exchange appearing to occur through the submucosal capillary network.