The Eustachian tubal function of skindivers based on X-rays and CT scans of their temporal bones

Abstract

The Eustachian tubal function was compared in 54 ears of 27 skindivers and 88 ears of 44 normal adults. The active opening function was determined by a sonotubometric Eustachian tubal function test, which measured the duration of patency of the Eustachian tube while swallowing. The passive opening function was determined by tubo-tympanoaerodynamic graphy (TTAG) and Valsalva's maneuver. Both X-ray and computed tomography examinations of the temporal bones were performed on 12 ears of 6 skindivers.
1) No significant differnce were found, regarding the duration of patency of the Eustachian tube while swallowing, between skindivers and normal adults. The opening pressure of the Eustachian tube during Valsalva's maneuver was defined as the naso-pharyngeus pressure. It was found that a higher pressure was required to open the Eustachian tube of skindivers than that of normal adults.
The longer skindivers had been diving, the higher the opening pressure of the Eustachian tube was. From the above results, it appeared that this higher mean pressure might be the resulted of the effect of ventilation training on the Eustachian tube due to the increased pressure in a hyperbaric environment.
2) Seven skindivers ears also revealed the presence of an underdeveloped pneumatization in their temporal bones. Eight skindiver ears also showed hypertrophy of the mastoid cell septa. These findings indicated that the osseous tissue surrounding the middle ear appeared to be a reaction to such stimuli as high pressure which is continually exerted in deep water.