Superiority of nitinol piston over conventional prostheses in stapes surgery: first comparative results in the Chinese population in Taiwan

Abstract

Background: A growing number of studies conducted on stapes surgery have suggested that firm and adequate attachment of the prosthesis onto the long process of the incus plays a key role in surgical success. For this reason, a new prosthesis made of Nitinol characterized by "self-crimping" has been developed. Although better postoperative outcomes achieved with a Nitinol piston have been previously confirmed, the superiority of the Nitinol piston over the conventional manual-crimping prostheses remains controversial. The aim of this study was to determine the advantages of the Nitinol piston with regard to hearing improvement.

Methods: We retrospectively compared postoperative hearing in otosclerosis surgeries with the Nitinol piston versus the manual-crimping prostheses. Sixteen surgeries with Nitinol pistons (carried out between April 2007 and August 2009) and 21 surgeries with conventional prostheses (carried out between January 2004 and January 2009) were evaluated. All patients received pure-tone audiograms preoperatively and postoperatively.

Results: In the Nitinol piston group, the air-bone gap (ABG) average (7.92 + or - 6.75 dBHL) was significantly smaller postoperatively than preoperatively (26.79 + or - 8.33 dBHL, p < 0.001). Similarly, the ABG average for the conventional piston group (13.09 + or - 6.99 dBHL) was significantly smaller postoperatively than preoperatively (26.19 + or - 6.76 dBHL, p < 0.001). Although both groups demonstrated an improvement in average ABG postoperatively, the Nitinol piston group showed a greater improvement than the conventional piston group (p = 0.018). Additionally, ABG closure within 10 dB was attained in significantly more patients (75%) in the Nitinol piston group compared with the conventional piston group (33.3%, p = 0.012).

Conclusion: The Nitinol piston has a distinct advantage over conventional prostheses, providing an easier, safer and more effective treatment option in otosclerosis surgery. To our knowledge, this is the first comparative analysis of hearing results of the Nitinol piston with conventional prostheses in the Chinese population in Taiwan. In this population, there is a much lower prevalence of otosclerosis, leading to a lack of surgical experience in otosclerosis surgery, even at large medical centers. This may explain, in part, the relative lack of studies conducted on stapes prostheses in Asian patients. Therefore, our preliminary research may provide a reference for future investigations on stapes surgery in Asian patients with otosclerosis based on ethnic differences.