Tubal and tympanic openings of the peritubal cells: implications for cerebrospinal fluid otorhinorrhea.

Cerebrospinal fluid otorhinorrhea after surgery for cerebellopontine angle tumors may persist despite obliteration of the mastoid, middle ear, and tympanic orifice of the eustachian tube. In this study, histologic sections of 120 adult temporal bones were examined by light microscopy to determine the incidence of peritubal pneumatization and to demonstrate the frequency of tubal and tympanic openings of the peritubal cells. The results of this study suggest that the pathway for these persistent cerebrospinal fluid leaks may be via the peritubal cells that open directly into the eustachian tube anterior to its tympanic orifice. Peritubal pneumatization was present in 78 (65%) of the temporal bones. Of the 57 specimens in which the openings of the peritubal cells could be identified, in 52 (91%), the cells opened into the eustachian tube anterior to its tympanic orifice, and in only five (9%), they opened into the middle ear. The overall incidence of tubal openings in this study was 59%. In 13 temporal bones (21%), the tubal opening were at a distance of > 5 mm anterior to the tympanic orifice of the eustachian tube. Therefore, cerebrospinal leak may persist through these tubal openings despite obliteration of the mastoid, middle ear, and tympanic orifice of the eustachian tube. A case of persistent cerebrospinal fluid leak in which extensive peritubal pneumatization was demonstrated by computed tomography scan is presented. Successful control of the leak was obtained only after the tubal openings of these cells several millimeters anterior to the tympanic orifice were obliterated.