Evaluation of Auditory Function after Stapedectomy in the Absence of the Other Ossicles

Abstract

96 stapedectomies (92 primary and 4 re-operations) were performed on 92 ears of 85 patients (on 7 patients bilaterally) between 1965 and February 1980. In addition to fixation of the stapes or footplate, a variety of different lesions of the sound-conducting apparatus required the use of a ‘drum to oval window’ columella. In each case, the body of the incus or an autogenous cortical bone columella connected the tympanic membrane with a fascia graft covering the oval window. Of the possible check-ups, the following have been performed so far: within 1 year, 95/96; longer than 1 year, 83/90; longer than 2 years, 65/73; longer than 5 years, 40/44; the longest possible 67/96. Comparison between the best results achieved and the data obtained at the latest follow-up shows that the results tend to deteriorate with time. An improvement in air conduction of 30 dB or more occurred in 48% of the cases, of more than 20 dB in 73%, no change was observed in 12%, and a deterioration in 1%. At the latest follow–up these figures had changed to 33, 52, 18 and 7%, respectively. In terms of the best results there is a 30-dB interval between the peaks of the curves indicating the distribution of the pre-operative and the post-operative air-bone gaps. According to the latest data this interval has decreased to 20 dB. In the majority of ‘unsuccessful’ cases, deterioration of the hearing improvement once achieved or the absence of post-operative improvement is associated with a wide air-bone gap. The cause of the conductive component in the hearing loss lies in factors other than the columella. No extrusion of the columella has been observed so far. Although pre-operative bone conduction deteriorated over the speech frequencies in 11 patients and at 4 000 Hz in 6, this process could also be observed in the non-operated ear. There was only 1 patient in whom a considerable deterioration occurred at 4 000 Hz, and in another at 500–4000 Hz only on the operated side. No immediate post-operative drop and no total deafness have occurred so far. The necessity of long-term follow-ups for judging any surgical technique of improving hearing is stressed.

Key Words:

• Stapedectomy
• ‘Atypical’
• Autogenous bone columella
• Surgery
• reconstructive
• Tympanoplasty