[Stapotomy with ultrasound? Animal experiment study of possible side effects]

Stapedectomy by ultrasound has been proposed as an alternative method for perforating the stapes footplate in surgery for otosclerosis. Possible functional adverse effects of ultrasound perforation of the otic capsule in guinea pigs were investigated in the present study by means of vestibular evoked potentials (VsEP). VsEP were elicited by pulsed linear accelerations applied to the animal's head following surgical removal of the middle ear, following intense ultrasound drilling around the otic capsule and after drilling a small hole in the anterior bony wall of the vestibule. All manipulations did not affect amplitudes and latencies of the early potential N1 (less than 1 msec after onset of acceleration). Significant alterations of N1 occurred following direct mechanical damage of the otolithic organs, indicating that VsEP can be used to detect lesions of these receptors and therefore may be used as a parameter of vestibular function in experimental animals. Findings indicate that perforation of the otic capsule by ultrasound is possible without inducing functional lesions of the otolithic organs.