Distortion product otoacoustic emissions following stapedectomy versus stapedotomy

To evaluate distortion product otoacoustic emissions following stapes surgery in patients with otosclerosis, and to compare in this respect two surgical techniques used in our department.

This retrospective study included 17 stapedectomy and 23 stapedotomy patients aged 16-68 years who had been followed up for at least 12 months. Distortion product otoacoustic emission results at 2, 3, 4 and 5 kHz (i.e. =f2, with 2f1 - f2 = 0.6f2) were obtained pre-operatively and four weeks post-operatively. The control group included 13 volunteers aged 18-50 years with normal hearing and normal otoscopic findings.

Distortion product otoacoustic emissions were detected pre-operatively in 34.8 per cent of stapedotomy patients and 29.4 per cent of stapedectomy patients, and post-operatively in 91.3 per cent of stapedotomy patients and 88.2 per cent of stapedectomy patients. The differences between the stapedotomy and stapedectomy groups were statistically insignificant for each tested frequency, both pre- and post-operatively. The patients' post-operative distortion product otoacoustic emission amplitudes were less than those of normal hearing individuals, even in patients with complete air-bone gap closure and a significant improvement in hearing.

Distortion product otoacoustic emissions were detected in most of our patients following successful stapes surgery, and appeared to be unaffected by the surgical technique or prosthesis used.