DIAGNOSTIC IMPORTANCE OF THE CARHART NOTCH IN PATIENTS WITH CHRONIC OTITIS MEDIA

Abstract

Objective
 The false sensorineural loss caused by otosclerosis
 due to stapes fixation is known as the Carhart notch.
 To examine the changes in air-bone gap (ABG)
 and bone-conduction (BC) hearing thresholds by
 comparing the preoperative and postoperative
 audiometry results in patients with chronic otitis media
 (COM), to investigate the effects of air conduction
 (AC) on BC, to determine the effects of postoperative
 improvement in AC on BC, to detect the presence
 of the Carhart notch in COM, and to determine the
 effects of surgery on the Carhart notch.
 Material and Methods
 A total of 104 patients who underwent type 1
 tympnoplasty between January 2012 - March 2017
 in our clinic were included in this retrospective study.
 Parameters measured during the preoperative and
 postoperative sixth month audiometric evaluation
 comprised AC hearing thresholds at the frequencies
 of 250-8,000 Hz, BC hearing thresholds at 500-4,000
 Hz, and ABG values at 500-4,000 Hz intervals.
 Results
 Before surgery, the Carhart notch was present in
 46 (44.2%) of the 104 patients. Postoperatively, the
 Carhart notch was observed to have been corrected
 in 25 (54.3%) of these patients (p=0.029).
 Conclusion
 After tympanoplasty, significant improvement in ABG
 may lead to improvement in BC at 2,000 Hz in COM
 cases with an intact and mobile ossicular chain. The
 Carhart notch may also be present in COM.