Prognostic evaluation of secretory otitis media as a function of mastoidal pneumatisation.

Fifty-two secretory otitis media (S.O.M.) ears with protracted course were compared roentgenologically (Schuller projection) with 52 S.O.M. ears which recovered after insertion of a single ventilating tube. Measurements were done first by comparing the pneumatised area millimetrically and later semiquantitatively according to the size of the mastoid cells--grading the mastoid cells from 1 (eburnize) to 10 (very big mastoid cells). S.O.M. ears with protracted chronic course showed an average mastoid area of 312 mm2, their cell size showing on the average a diploic or small-diploic cells--corresponding to grade 3.5. On the other hand, S.O.M. ears which recovered promptly had an average mastoid area of 440 mm2, and their mastoid cells began to show as actual cells (small up to medium cells), corresponding to grade 5.7. The difference, both millimetrically and grade-wise, between the two groups was found to be very significant (P greater than or equal to 0.01). We may conclude that the prognosis of S.O.M. is related to the size of their mastoid cells or alternatively to the amount of air in the middle ear cleft as a whole.