Evaluation and Management of Spontaneous Temporal Bone Cerebrospinal Fluid Leaks

Abstract

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