Study of the improvement in bone conduction threshold after stapedectomy. / Evaluación del cambio en el umbral de la vía ósea en pacientes operados de estapedectomía.

ABSTRACT

INTRODUCTION AND OBJECTIVES: Bone conduction threshold depression is not always a result of inner ear and cochlear nerve pathology. In fact, middle ear pathologies may be responsible for such threshold depression, as occurs in otosclerosis. The aims of this study were to evaluate the improvement of bone conduction threshold in patients with otosclerosis that underwent stapedectomy and to study the postoperative audiological results. MATERIAL AND METHODS: This was a retrospective study on 95 patients (116 ears) diagnosed with otosclerosis having conductive or mixed hearing loss that received surgery (stapedectomy and complete removal of the footplate) consecutively. Audiometry was performed on all patients pre- and postoperatively (one month and one year after surgery). Bone and air conduction thresholds were measured at 4 frequencies (500, 1000, 2000 and 4000Hz). RESULTS: The air-bone gap was closed, with a residual air-bone gap below 10dB in 92.2% of the patients and below 5dB in 79.3% of the cases. The air conduction threshold improved an average of 25dB. The patients that had an affected bone conduction threshold preoperatively improved bone conduction postoperatively at the frequencies of 1000 and 2000Hz (6 and 12dB, respectively). Consequently, the Carhart notch disappeared on the audiogram. These results were maintained at one year of follow up. CONCLUSIONS: We found a significant improvement in the bone conduction threshold at the frequencies of 1000 and 2000Hz and a disappearance of the Carhart notch in the audiogram after stapedectomy and total footplate removal in patients diagnosed with otosclerosis having mixed hearing loss.