EVALUATION AND MANAGEMENT OF SPONTANEOUS TEMPORAL BONE CEREBROSPINAL-FLUID LEAKS

Spontaneous temporal bone cerebrospinal fluid leak may be defined as a leak without an apparent precipitating cause. These transdural fistul as occur rarely, and diagnosis is predicated upon a high index of susp icion. Leaks have been reported through both middle and posterior foss a defects, although the vast majority involve the middle fossa plate. In a previous study we reported 7 cases of spontaneous temporal bone c erebrospinal fluid leaks, all involving the middle fossa tegmen. Upon further review of these cases and 5 previously unreported cases, the d efect was localized to the tegmen tympani in 9 of the total 12 cases. Diagnostic methods are discussed, with the importance of high-resoluti on computed tomography stressed. The role of contrast cisternography i s also evaluated. An outline for surgical management is presented base d upon residual hearing and defect location and accessibility. A trans mastoid procedure offers the advantage of visualization of both the mi ddle and posterior fossa plates, and this approach can be supplemented with an obliterative procedure when indicated. The middle fossa appro ach provides optimal exposure of the tegmen plate with less likelihood of ossicular injury when dealing with tegmen tympani defects. Adjunct s to surgical therapy include intrathecal fluorescein dye and continuo us postoperative lumbar cerebrospinal fluid drainage.