Retrospective analysis of the results of implanting Nitinol pistons with heat-crimping piston loops in stapes surgery

Abstract

The study presented here evaluates the hearing results after the implantation of a new nickel-titanium (Nitinol) prosthesis in stapes surgery; on heating, this prosthesis crimps itself around the long process of the incus. In addition, we compare the outcome with results published in the literature. The medical records of all patients who underwent surgery for otosclerosis with implantation of a Nitinol piston during the period 2004-2006 were evaluated retrospectively. 83 patients (58 women and 25 men), with a provisional diagnosis of otosclerosis that was confirmed during surgery in all but one of the cases, were treated by primary stapes surgery (85 ears). We were able to include 53 patients (55 ears) who had audiograms with air and bone conduction preoperatively and both 2-6 weeks and about 1 year after surgery. We found a mean air-bone gap (ABG) for the frequencies 0.5, 1, 2 and 4 kHz (ABG4000) of 10.4 ± 5.5 dB after a mean postoperative follow-up period of 24.5 ± 16 days, and of 7.4 ± 3.7 dB after 462 ± 119 days. For the frequencies 0.5, 1, 2 and 3 kHz (ABG3000), the results were 9.1 ± 4.8 and 6.4 ± 3.9 dB. The differences in preoperative versus postoperative air-bone gap, referred to as ABGC, after 25 and 462 days, respectively, were 19.4 ± 8.9 and 22.3 ± 8.8 dB for AGB4000, and 19.5 ± 8.8 and 22.2 ± 8.9 for ABG3000. Very good results were achieved with a new nickel-titanium prosthesis that crimps itself around the long process of the incus, thus facilitating stapes surgery and at the same time stabilizing the high quality of the results. However, no long-term results after 10 years or more, which would allow a final judgment, are yet available.