Changes in Bone Conduction after oval Window Fenestration

Abstract

Data are reported on 116 cases of oval window fenestration in which the pre- and post-operative bone conduction thresholds were compared. It appeared that in this series there was significant improvement post-opera-tively at all frequencies, the changes being larger at 1000 and 2000 cps (5.5 to 5.7 db) than at 250, 500 and 4000 cps (2.2 to 2.8 db). The incidence of improvement was largest in “C” cases and diminished with better preoperative bone conduction figures. Results comparing the bone conduction thresholds with the tested ear open or closed showed that the latter technique introduces slight error in the post-operative thresholds, some improvement occurring via air conduction, which is now nearly normal. The value of speech tests in pre-operative selection is emphasized.