Finite element model simulates cephalic trim, nasal tip stability
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A computerized finite element model of the human nose was able to simulate cephalic trim, including tip depression and tissue migration, according to recently published study results.
Ryan P. Leary, MD, and colleagues used maxillofacial CT of a healthy patient undergoing rhinoplasty with 1-mm axial resolution to create a multicomponent finite element model (FEM) using 3-D medical imaging. Control, conservative trim and aggressive trim models were created, with each imported to a multiphysics software program that performs mechanical simulations.
“First, nasal trip depression (palpation) was simulated, and the resulting stress distribution was calculated for each model,” the researchers wrote. “Second, long-term tissue migration was simulated on conservative and aggressive trim models by placing normal and shear force vectors along the caudal and cephalic borders of the tissue defect.”
All three simulations had consistent findings under the von Mises stress distribution created by a 5-mm tip depression. The medial portion of the intermediated crus and caudal septum had concentrations of high stress.
When more lower lateral cartilage tissue was resected, nasal tip reaction force had marginal decrease.
A degree of alar rim retraction and tip rotation were produced by both conservative and aggressive cephalic trim models, “which increased with the magnitude of the force applied to the region of the tissue defect,” the researchers wrote.
“Our models indicate that a minimum width of lower lateral cartilage is necessary to minimize tip rotation and alar rim retraction,” the researchers concluded. “This form of analysis has the potential to elucidate the effects of other rhinoplasty maneuvers on nasal tip mechanics. Through the use of FEM analysis, our structural simulations will inform the surgeon how the mechanics of the nasal tip are affected by structural changes in the lower crura.” – by Bruce Thiel
Disclosure: The researchers report no relevant financial disclosures.