Mastoid pneumatization in otosclerosis.

The extent of mastoid pneumatization in 150 otosclerotic ears was compared with that of 150 healthy control ears. The size of mastoid pneumatization was measured by use of the Schüller lateral x-ray projection with the help of computed planimetry. The measurements showed the average pneumatized area in otosclerotic ears to be 17.4 +/- 5 cm2, in contrast to 12.9 +/- 4 cm2 for the healthy control ears. The difference between the two groups was highly significant (p less than .0001). While both groups showed a bell-shaped distribution of the measured pneumatized area, the curve of the otosclerotic ears was shifted significantly to the right. Our findings indicate a link between otosclerosis on the one hand and highly pneumatized mastoids on the other. This link between a hereditary disease and a specific type of pneumatization points to the likelihood that heredity also plays some role in determining the final type of pneumatization.