What happens between pure hydraulic and buckling mechanisms of blowout fractures?
OBJECTIVE
The present study aims to evaluate how the ratio of the hydraulic and buckling mechanisms affects blowout fracture patterns, when these two mechanisms work simultaneously.


METHODS
Three-dimensional computer-aided-design (CAD)models were generated simulating ten skulls. To simulate impact, 1.2J was applied on the orbital region of these models in four patterns. Pattern 1: All the energy works to cause the hydraulic effect. Pattern 2: Two-thirds of the energy works to cause the hydraulic effect; one-third of the energy works to cause the buckling effect. Pattern 3: One-third of the energy works to cause the hydraulic effect; two-thirds of the energy works to cause the buckling effect. Pattern 4: The entire energy quantum works to cause the buckling effect. Using the finite element method, the regions where fractures were theoretically expected to occur were calculated and were compared between the four patterns.


RESULTS
More fracture damage occurred for Pattern 1 than Pattern 2, and for Pattern 3 than for Pattern 4.


CONCLUSIONS
The hydraulic and buckling mechanisms interact with one another. When these two mechanisms are combined, the orbital walls tend to develop serious fractures.
Nagasao
Tomohisa
T
Department of Plastic and Reconstructive Surgery, School of Medicine, Keio University, Tokyo, Japan. nagasao@sc.itc.keio.ac.jp
Miyamoto
Junpei
J
Shimizu
Yusuke
Y
Jiang
Hua
H
Nakajima
Tatsuo
T
D001696:Biomechanical Phenomena; D003198:Computer Simulation; D017076:Computer-Aided Design; D020342:Finite Element Analysis; D006801:Humans; D008422:Materials Testing; D008953:Models, Anatomic; D009917:Orbital Fractures / Q000209:etiology / Q000503:physiopathology; D013314:Stress, Mechanical