Learning Objectives:

Introduction: Development of the mastoid air cell system in children with congenital cholesteatoma is said to be relatively good. However we sometimes encounter cases with poorly developed mastoid air cell system, but there have been few quantitative studies about the matter. The present study was undertaken in order to clarify the relationship between development of the mastoid air cell system in children with congenital cholesteatoma and various clinical factors.

Methods: Development of the mastoid air cell system of 53 children with congenital cholesteatoma was evaluated. The size of mastoid cells were measured from 0.5 mm sliced sectioned computed tomography scan of the temporal bone.

The sum of two areas, one showing the lateral semicircular canal and the other, 3 mm below it, was defined as the cross-section area of the pneumatized mastoid cells. Age, episode of otitis media, extension stage and location of the cholesteatoma, and size of the pneumatized mastoid cells were evaluated. Stage of the cholesteatoma was estimated with the grading system described by Potsic et al.

Results: The cross-section area of the affected side was significantly smaller than that of the unaffected side and this tendency was remarkable especially in the elder cases. The group with episode of otitis media was smaller in area than that without it. Cases with severe invasion of the cholesteatoma had smaller in area than that of others. Whether cholesteatoma present close to auditory tube or not made no difference in the development of the mastoid.

Conclusions: The mastoid cells in the ear of children with congenital cholesteatoma were poorly pneumatized compared with those of the unaffected side, and our data indicate that the suppression factor of pneumatization may be episode of otitis media, high age, and cholesteatoma presented in the mastoid portion.