Carhart Notch-A Prognostic Factor in Surgery for Otosclerosis.

Otosclerosis is an underlying disease of the bony labyrinth. This disorder, occurring only within the area of a person's temporal bone, is characterized by a progressive hearing loss and tinnitus. The study looked for the answer to the question of whether the presence or absence of Carhart notch in the presurgical tonal audiogram affects the final outcome of the otosclerosis surgery. The analysis included 140 patients operated on for the first time due to otosclerosis between 2010 and 2016. The study group consisted of 107 women aged from 19 to 62 (average age: 40.33) and 33 men aged 27 to 59 (average age: 38.23). Analysis showed a statistically better result of stapedotomy in patients without the notch than in the same procedure in patients with the notch present. The opposite situation occurred in the case of stapedectomy. (1) The presence of a refraction of the bone conduction curve with a depth of 10 to 20 dB at a frequency of 2000 Hz (the so-called Carhart notch) in the presurgical tonal audiogram is an unfavorable prognostic factor in relation to closing the cochlear reserve and improving bone conduction after the stapedotomy. (2) Regardless of the presence or absence of Carhart notch in the presurgical tonal audiogram, stapedotomy is the procedure with the highest efficiency in the treatment of otosclerosis.