Treatment of otosclerosis with a superelastic nitinol piston: first results

Abstract

Stapedotomy with implantation of an alloplastic prosthesis is a well-established therapy for the treatment of otosclerosis. Since the middle of 2008, a new Nitinol prosthesis with memory function and superelastic properties has been available which is expected to make fixation on the long process of the incus much easier. The advantage of this prosthesis is that heat-induced wire crimping is no longer necessary and damage to the incus caused by heat is avoided. Since May 2008, laser-assisted stapedotomy with implantation of a Nitinol prosthesis was performed in 21 patients suffering from otosclerosis. The prostheses used for all patients had a size of 4.5 mm × 0.4 mm. The patient collective consisted of 14 women and 7 men with a mean age of 53.4 years. Pre- and postoperatively, an ENT examination was carried out followed by an audiological evaluation of the hearing result. In addition, the properties of the prosthesis ("proper fitt", "handling", and "overall rating") were evaluated intraoperatively by means of a test protocol. The Nitinol prosthesis was implanted successfully in all 21 patients. The mean air-bone gap for the frequencies from 0.5 to 4 kHz was 9.83 dB postoperatively. Intraoperatively, the fit of the prosthesis was rated as "good to very good", the handling as "good" and the overall rating of the system was "good to very good". Our patient collective showed good postoperative hearing results. Due to simple intraoperative handling, especially placing the Nitinol prosthesis in position, the critical work step of crimping is no longer necessary.

Keywords: Air-bone gap; Nitinol; Otosclerosis; Stapedotomy.

Fig. 1

Self-Crimping Super Elastic NITINOL Piston and animation of fixation to the long process of the incus (by kind permission of Audio Technologies, distributed by Spiggle & Theis Medizintechnik GmbH)

Fig. 2

Self Crimping Super Elastic NITINOL Piston positioned at small alligator jaws forceps

Fig. 3

Average pre- and postoperative (green = preoperative, orange = postoperative) air-bone gap in dB with different frequencies in Hz

Fig. 4

Average pre- and postoperative (green = preoperative, orange = postoperative) hearing threshold in dB with different frequencies in Hz

Fig. 5

Average evaluation of prosthesis properties from the test protocol. Rated on a 1–5 scale (1 = very poor; 5 = very good)