Postoperative functional evaluation

Abstract

Audiological evaluation after middle ear surgery should describe middle ear function and cochlear losses related to surgery. This paper concentrates on the evaluation of the mechanical success of surgery. The air-bone gap is the most direct measure of acoustic middle ear function. However, the bone conduction (BC) thresholds do not only reflect cochlear function, but also abnormalities in the external and middle ear. Depressed BC thresholds improving with surgery are well known in cases of otosclerosis (Cahart notch) but similar phenomena are often recorded after surgery for chronic otitis media. The BC improvement is most pronounced after successful surgery for advanced middle ear pathology, i.e. the cases with the greatest hearing improvement. Therefore, if one wishes to describe postoperative middle ear function with the air-bone gap, the postoperative BC threshold should be the reference. Otherwise, the size of the postoperative air-bone gap would be unduly influenced by preoperative middle ear pathology.