title: Nitinol-teflon stapes prosthesis improves low-frequency hearing results after stapedotomy.
abstract: 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.
  
  
  METHODS
  Retrospective chart review.
  
  
  METHODS
  One hundred eighty-eight consecutive ears with either a platinum or a nitinol piston and primary stapes surgery between 1998 and 2009.
  
  
  METHODS
  Subspecialty private practice.
  
  
  METHODS
  One hundred forty-four ears received a platinum 0.6-mm-diameter piston, and 44 ears received a nitinol 0.6-mm-diameter piston.
  
  
  METHODS
  American Academy of Otolaryngology-Head and Neck Surgery guidelines, including 4-frequency pure-tone average air-bone (AB) gap, and success (gap <or= 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Seattle Ear Clinic, Seattle, Washington 98122-4328, U.S.A. chasmangham21@msn.com
authors.forename: Charles A
authors.initials: CA
authors.lastname: Mangham
mesh_terms: D000497:Alloys; D001672:Biocompatible Materials; D001844:Bone Conduction / Q000502:physiology; D019929:Cochlear Implantation; D003054:Cochlear Implants; D005500:Follow-Up Studies; D006309:Hearing / Q000502:physiology*; D006801:Humans; D010984:Platinum; D011138:Polytetrafluoroethylene; D012189:Retrospective Studies; D013201:Stapes Surgery; D016896:Treatment Outcome
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; C013616:nitinol; D010984:Platinum; D011138:Polytetrafluoroethylene