Dry fenestra novovalis operation; technique for restoration and conservation of serviceable hearing in clinical otosclerosis.

Abstract

The labyrinthitis that has often followed fenestration operations was explained in part by the appearance of blood in the perilymph space but also in part by the use of irrigating solutions which did not duplicate the unknown composition of the perilymph. The irrigation necessary for the removal of bone dust is now done before opening the perilymph space, and the subsequent creation of bone dust can be avoided by removing the bony cupola intact instead of using the pulverization technique. One hundred fenestration operations have been performed alternately with and without irrigation, so that in 50 patients the ear was irrigated and in 50 it was not. Bleeding into or within the perilymph space was prevented in every one. There was labyrinthitis of some degree of severity in each of the 50 irrigated cases, and it was absent in all of the 50 nonirrigated cases. The new vestibular fenestra must be made in a region out of reach of the spreading otosclerotic lesion, for permanency of effect; for acoustical reasons, the fenestra is placed outside of the middle ear. The middle ear space is acoustically sealed off. The new vestibular fenestra being likewise covered and sealed off, and being without any direct connection with the middle ear, a maximum difference in sound pressure between them is attained. This gives the most marked and most lasting possible improvement in hearing.