Human cochlear diffusion from the cerebrospinal fluid space with gadolinium contrast.

Inner ear drug delivery has traditionally involved lateral approaches to the cochlea, including transtympanic injection, round window injection, oval window injection, cochleostomy, and semicircular canal (SSC) fenestration. The connection between cochlear fluid spaces and the cerebrospinal fluid (CSF) space, on the other hand, remains poorly understood. This connection has important implications for routes of therapeutic administration.