What happens between pure hydraulic and buckling mechanisms of blowout fractures?

Nagasao, Tomohisa; Miyamoto, Junpei; Shimizu, Yusuke; Jiang, Hua; Nakajima, Tatsuo

doi:10.1016/j.jcms.2009.09.001

« Previous Next »Journal of Cranio-Maxillo-Facial Surgery
Volume 38, Issue 4 , Pages 306-313, June 2010

What happens between pure hydraulic and buckling mechanisms of blowout fractures?

Tomohisa Nagasao, MD, PhD
- Department of Plastic and Reconstructive Surgery, School of Medicine, Keio University (Head: Tatsuo Nakajima, MD), Tokyo, Japan
- Tomohisa NAGASAO, MD, PhD, Department of Plastic and Reconstructive Surgery, Keio University Hospital, Shinjuku-Ward Shinanomachi 35 Tokyo, Japan. Tel: +81 3 5363 3814; Fax: +81 3 3352 1054
Junpei Miyamoto, MD
- Department of Plastic and Reconstructive Surgery, School of Medicine, Keio University (Head: Tatsuo Nakajima, MD), Tokyo, Japan
Yusuke Shimizu, MD
- Department of Plastic and Reconstructive Surgery, School of Medicine, Keio University (Head: Tatsuo Nakajima, MD), Tokyo, Japan
Hua Jiang, MD, PhD
- Department of Plastic Surgery, ChangZheng Hospital, Second Military Medical University (Head: Hua Jiang), Shanghai, China
Tatsuo Nakajima, MD, PhD
- Department of Plastic and Reconstructive Surgery, School of Medicine, Keio University (Head: Tatsuo Nakajima, MD), Tokyo, Japan

Received 20 November 2008; accepted 2 September 2009. published online 02 November 2009.

Summary

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.

Materials and 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.

Conclusion

The hydraulic and buckling mechanisms interact with one another. When these two mechanisms are combined, the orbital walls tend to develop serious fractures.

Keywords: blowout fracture, simulation, orbit, finite element method