Abstract
This study presents an analytical investigation into the mechanical behavior of a
cartilage-polydioxanone (PDS) plate composite grafts. Numerical methods are used to
provide a first-order, numerical model of the flexural stiffness of a cartilage-PDS
graft. Flexural stiffness is a measure of resistance to bending and is inversely related
to the amount of deformation a structure may experience when subjected to bending
forces. The cartilage-PDS graft was modeled as a single composite beam. Using Bernoulli-Euler
beam theory, a closed form equation for the theoretical flexural stiffness of the
composite graft was developed. A parametric analysis was performed to see how the
flexural properties of the composite model changed with varying thicknesses of PDS
foil. The stiffness of the cartilage-PDS composite using 0.15-mm-thick PDS was four
times higher than cartilage alone. The composite with a 0.5-mm-thick PDS graft was
only 1.7 times stiffer than the composite with the 0.15-mm-thick PDS graft. Although
a thicker graft material will yield higher flexural stiffness for the composite, the
relationship between composite stiffness and PDS thickness is nonlinear. After a critical
point, increments in graft thickness produce gradually smaller improvements in flexural
stiffness. The small increase in stiffness when using the thicker PDS foils versus
the 0.15 mm PDS foil may not be worth the potential complications (prolonged foreign
body reaction, reduction in nutrient diffusion to cartilage) of using thicker artificial
grafts.
Keywords
facial plastic surgery - polydioxanone - cartilage - elastic modulus - rhinoplasty
