Nitinol-teflon stapes prosthesis improves low-frequency hearing results after stapedotomy

Objective: To determine if nitinol-Teflon shape-memory stapes prostheses offer a hearing result advantage compared with platinum-Teflon pistons that must be manually crimped. Study Design: Retrospective chart review. Patients: One hundred eighty-eight consecutive ears with either a platinum or a nitinol piston and primary stapes surgery between 1998 and 2009. Setting: Subspecialty private practice. Intervention: One hundred forty-four ears received a platinum 0.6-mm-diameter piston, and 44 ears received a nitinol 0.6-mm-diameter piston. Main Outcome Measures: American Academy of Otolaryngology-Head and Neck Surgery guidelines, including 4-frequency pure-tone average air-bone (AB) gap, and success (gap ≤ 10 dB) rate. Results: Success at closing the AB gap was comparable for both groups (platinum, 96%; nitinol, 92%; p = not significant). The nitinol group had significantly smaller mean AB gaps in the lower frequencies (at 250 Hz, 9.3 versus 15.4 dB and at 500 Hz, 1.9 versus 5.0 dB; p's < 0.01), but not at 1, 2 or 4 kHz. The highly malleable platinum loop was adaptable to various incus diameters and was easy to crimp. The 360-degree circumferential version of the nitinol prosthesis may adapt to various incus diameters better than the original version (minimum heat-crimped diameter, 0.70 versus 0.76 mm). In some cases, both nitinol versions were difficult to crimp using only a laser, and a manual crimp was also required. Conclusion: The nitinol stapes prostheses failed to live up to claims of consistent ease of crimping; however, the significantly better low-frequency hearing results justify an effort to make the devices more user friendly. © 2010, Otology & Neurotology, Inc.