B-ENT

Otosclerosis: Shift in bone conduction after stapedotomy

1.

Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals of Leuven, Leuven, Belgium

2.

Department of Neurosciences, Research Group ExpORL

3.

Master of Science in Speech and Language Pathology and Audiology Sciences, University of Leuven, Leuven, Belgium

B-ENT 2015; 11: 183-189
Read: 827 Downloads: 563 Published: 04 February 2020

Otosclerosis: Shift in bone conduction after stapedotomy. Objectives: To analyze changes in bone conduction (BC) thresholds before and after stapedotomy in patients with clinical otosclerosis with a focus on the Carhart notch, which is defined as a significant loss of BC at a certain audiometric frequency.

Methodology: Retrospective case review of pure tone audiometry (PTA) in 213 patients who underwent a stapedotomy at a tertiary referral center between 2004 and 2011. The patients were grouped by age and the frequency of the Carhart notch. The non-operated ear was also evaluated.

Results: The Carhart notch was present on pre-operative audiometry in 158 (74%) patients at 0.5 (n=18, 8.45%), 1 (n=25, 11.70%), or 2 kHz (n=115, 54.0%). We measured a mean postoperative improvement in BC of 7.5, 8.4, and 8.8 dB HL. Pre-operatively, 55 (25.8%) patients did not exhibit a typical notch configuration. The mean gain in BC, defined on PTA according to the AAO-HNS criteria (0.5, 1, 2 and 3, or 4 kHz), was 1.8 dB HL after stapedotomy.

Conclusion: The Carhart notch was not solely related to the 2 kHz frequency. The greatest gain in BC after stapedotomy for otosclerosis occurred at the notch frequency.

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EISSN 2684-4907