title: Ex Vivo Mechanical Evaluation of a Sternal ZipFix(®) Implant for Prosthetic Laryngoplasty in Horses.
abstract: OBJECTIVE
  To evaluate the properties of a ZipFix(®) (ZipFix) implant in equine laryngeal cartilages.
  
  
  METHODS
  Ex vivo biomechanical study.
  
  
  METHODS
  Equine arytenoid (n=36) and cricoid cartilages (n=18).
  
  
  METHODS
  Suture bites were placed in arytenoid or cricoid cartilages using a ZipFix(®) implant or a single strand of USP 5 braided polyester (TiCron™), and arytenoid and cricoid cartilages were separately subjected to single load to failure (25 N preload) or cyclic loading for 1,000 cycles, followed by single load to failure. Load, distraction, and stiffness were recorded.
  
  
  RESULTS
  Four arytenoid-ZipFix cartilages fractured on implant placement. Under single load, arytenoid-ZipFix (n=9) failed at a greater mean load (359.01 ± 57.98 N) than arytenoid-Ticron (159.11 ± 22.98 N; n=12; P<.001). Arytenoid-ZipFix stiffness (31.32 ± 4.26 N/mm) was significantly greater than arytenoid-Ticron (13.18 ± 2.60 N/mm; P<.001). Cricoid-ZipFix stiffness (20.83 ± 3.37 N/mm) was significantly greater than cricoid-Ticron (13.6 ± 3.82 N/mm; n=6; P=.006). Under cyclic load, arytenoid-ZipFix distraction (2.53 ± 0.63 mm; n=5) was significantly less than arytenoid-Ticron (5.06 ± 1.37 mm; n=6, P=.006). After cyclic load, arytenoid-ZipFix failure load (295.16 ± 54.95 N) was significantly greater than arytenoid-Ticron (127.69 ± 32.67 N; P=.002). Arytenoid-ZipFix stiffness (35.59 ± 1.58 N/mm) was significantly greater than arytenoid-Ticron (24.10 ± 6.85 N/mm; P=.019).
  
  
  CONCLUSIONS
  In arytenoid cartilages, the sternal ZipFix(®) implant was significantly stronger and stiffer compared to a single strand of Ticron. During placement of the ZipFix(®) implant, frequent arytenoid cartilage failure occurred before testing, suggesting the implant is not suitable for clinical application.
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia.
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Markwell
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia.
authors.forename: P O Eric
authors.initials: PO
authors.lastname: Mueller
mesh_terms: D000818:Animals; D001193:Arytenoid Cartilage / Q000601:surgery; D001696:Biomechanical Phenomena; D003413:Cricoid Cartilage / Q000601:surgery; D005260:Female; D006734:Horse Diseases / Q000601:surgery*; D006736:Horses; D007818:Laryngeal Diseases / Q000601:surgery / Q000662:veterinary*; D058753:Laryngoplasty / Q000662:veterinary*; D008297:Male; D019736:Prostheses and Implants; D013537:Sutures / Q000662:veterinary