Ten-year outcomes with the shape memory Nitinol stapes prosthesis

Self-crimping pistons were introduced to remove the manual component of the crimping process during stapedectomy. Stapes prostheses made of the shape memory alloy, Nitinol, return to an original pre-set shape upon the application of heat above 45 degrees. This produces a closed loop which theoretically maintains a closed shape in uniform contact around the incus. Results from the senior author’s previous publication demonstrated significantly reduced mean postoperative air bone gap (ABG) and inter-individual variation of the ostoperative ABG using a Nitinol prosthesis as compared to a conventional titanium prosthesis and stable results up to two years postoperatively.2,3 Other groups have found stable early and intermediate term hearing results quivalent to or better than those achieved using conventional prostheses.4-12 In the long term, reports of stapes surgery using conventional prostheses demonstrate an average deterioration of 0.4-1.1 dB/year in air conduction (AC) thresholds.13-16 The objective of this study was to assess the long-term clinical hearing outcomes and their stability following stapedectomy using a self-crimping shape memory prosthesis over a ten-year period.