title: Mechanical analysis of the effects of cephalic trim on lower lateral cartilage stability.
abstract: OBJECTIVE
  To determine how mechanical stability changes in the lower lateral cartilage (LLC) after varying degrees of cephalic resection in a porcine cartilage nasal tip model.
  
  
  METHODS
  Alar cartilage was harvested from fresh porcine crania (n = 14) and sectioned to precisely emulate a human LLC in size and dimension. Flexural mechanical analysis was performed both before and after cephalic trims of 0 (control), 4, and 6 mm. Cantilever deformation tests were performed on the LLC models at 3 locations (4, 6, and 8 mm from the midline), and the integrated reaction force was measured. An equivalent elastic modulus of the crura was calculated assuming that the geometry of the LLC model approximated a modified single cantilever beam. A 3-dimensional finite element model was used to model the stress distribution of the prescribed loading conditions for each of the 3 types of LLC widths.
  
  
  RESULTS
  A statistically significant decrease (P = .02) in the equivalent elastic modulus of the LLC model was noted at the most lateral point at 8 mm and only when 4 mm of the strut remained (P = .05). The finite element model revealed that the greatest internal stresses was at the tip of the nose when tissue was flexed 8 mm from the midline.
  
  
  CONCLUSIONS
  Our results provide the mechanical basis for suggested clinical guidelines stating that a residual strut of less than 6 mm can lead to suboptimal cosmetic results owing to poor structural support of the overlying skin soft-tissue envelope by an overly resected LLC.
authors.affiliation: Department of Otolaryngology, University of California-Irvine, 19182 Jamboree Rd., Irvine, CA 92697, USA. soliaei@uci.edu
authors.forename: Sepehr
authors.initials: S
authors.lastname: Oliaei
authors.forename: Cyrus
authors.initials: C
authors.lastname: Manuel
authors.forename: Dmitriy
authors.initials: D
authors.lastname: Protsenko
authors.forename: Ashley
authors.initials: A
authors.lastname: Hamamoto
authors.forename: Davin
authors.initials: D
authors.lastname: Chark
authors.forename: Brian
authors.initials: B
authors.lastname: Wong
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D020342:Finite Element Analysis; D008953:Models, Anatomic; D055171:Nasal Cartilages / Q000502:physiology / Q000601:surgery*; D012225:Rhinoplasty / Q000379:methods*; D013314:Stress, Mechanical; D013552:Swine; D016474:Weight-Bearing