Age-related changes in the morphological relationship between the supratubal recess and the Eustachian tube

To study age-related changes in the morphology of the supratubal recess (STR) and its relationship with the Eustachian tube (ET).

Seventy randomly selected computed tomography (CT) images of non-pathological temporal bones of 49 patients were reviewed retrospectively. The patients were grouped according to age into 4 age groups: group A (0-3 years), group B (4-8 years), group C (9-18 years) and group D (19-50 years). Space analytic geometry was assessed to directly calculate the morphology of the STR and the ET.

In normal temporal bones, the STR was mostly presented with a solitary cell in life. The length of the STR was significantly longer in group C than that in group A (P<0.05). The width of the STR was declined with age and presented with significant difference among age groups (P<0.05). No significant difference was observed in the height of the STR in whole age groups (P>0.05). The aeration of the STR was intimately related with age-related morphological changes in the ET. But the important factors influencing the aeration of the STR were not always the same in different age stages.

The extended length and declined width of the STR with age were mostly related with the prolonging bony part and inwardly bending cartilaginous part of the ET in children and adolescent aged from 0 to 18 years old. In adults aged more than 18 years old, the narrowed caliber of the tympanic orifice of the ET could induce the decline in the width of the STR with age, but unfolded horizontal cartilaginous part of the ET contributed to stable length and height in aeration of the STR.