title: Defining nasal cartilage elasticity: biomechanical testing of the tripod theory based on a cantilevered model.
abstract: OBJECTIVE
  To define the modulus of elasticity for nasal septum, auricular, upper lateral, and lower lateral cartilages.
  
  
  METHODS
  Prospective enrollment of sequential patients undergoing septorhinoplasty. Test samples were obtained through routine surgical interventions using atraumatic harvesting techniques. The modulus of elasticity was determined using a customized biomechanical testing device. A clinical analysis of nasal tip strength and "ethnic" nasal categorization was performed.
  
  
  RESULTS
  Five sequential patients were enrolled; 4 underwent biomechanical testing of harvested cartilage. All 4 patients were classified as having a leptor-rhine nasal architecture. The modulus of elasticity for the lower lateral cartilages was 1.82 to 15.28 MPa. Values for auricular, nasal septum, and upper lateral cartilages (medial and caudal) were also determined.
  
  
  CONCLUSIONS
  This is the first biomechanical study performed on human auricular, lower lateral, and upper lateral cartilages. The elastic modulus can be determined from samples obtained during routine septorhinoplasty. The modulus of elasticity for all areas was significantly higher than values previously demonstrated for bioengineered elastic cartilage and carved human nasal septal specimens. Shaving the lateral portions of the nasal septum may significantly reduce tensile strength, which may affect graft performance in vivo. Further refinement of testing methods and an increase in the number of analyzed samples are required for formal statistical analysis and further determination of clinical relevance in different nasal subtypes.
authors.affiliation: Department of Otolaryngology, State University of New York Downstate Medical Center, Brooklyn, NY, USA. doctor@newyorknose.com
authors.forename: Richard W
authors.initials: RW
authors.lastname: Westreich
authors.forename: Hayden-William
authors.initials: HW
authors.lastname: Courtland
authors.forename: Philip
authors.initials: P
authors.lastname: Nasser
authors.forename: Karl
authors.initials: K
authors.lastname: Jepsen
authors.forename: William
authors.initials: W
authors.lastname: Lawson
mesh_terms: D001696:Biomechanical Phenomena; D002356:Cartilage / Q000502:physiology*; D004548:Elasticity; D006801:Humans; D008954:Models, Biological; D009666:Nose / Q000033:anatomy & histology* / Q000502:physiology*; D011446:Prospective Studies; D012225:Rhinoplasty; D012984:Software; D020858:Tissue and Organ Harvesting / Q000379:methods