Engineering Used to Design Facial Bones
Scientists are using the engineering technology behind the creation of high-performance aircraft components to design 3-D models for the replacement of delicate and complex facial bones lost to cancer surgery or trauma.
The researchers, combining engineering and plastic surgery expertise, have used a computational technique called topological optimization to design an experimental 3-D structure that can withstand the forces of chewing, facilitate speaking and swallowing, and replace large portions of the facial skeleton. The work is focused on the center of the face, home to the most complicated bony structures in the human head.
Eventually, the team plans to use tissue engineering techniques to grow bone around these lightweight structures and implant the new bone during facial reconstruction surgeries. The researchers predict that fully functional bone replacements based on these structural designs could be in use in operating rooms within 10 years.
Advances in reconstruction could reduce disfigurement among head and neck cancer patients and victims of such traumas as gunshot or blast wounds, including war injuries. The U.S. Department of Defense declared its interest in improving facial reconstruction with the 2008 establishment of the Armed Forces Institute of Regenerative Medicine.
Current plastic surgery techniques involve using a patient’s own bones – typically portions of the fibula in the lower leg – to piece together a relatively crude bone replacement during facial reconstruction.
“The difference between what is done now and our design is that we take into account all of the loads on the structure. And this is not a generic shape. For each person, we could create a patient-specific design” said Alok Sutradhar, a postdoctoral researcher in plastic surgery at Ohio State and lead author of the paper describing the work.
Sutradhar is trained as an engineer, with a specialty in 3-D computational modeling and a background in working with multifunctional high-performance lightweight materials used in space shuttle tiles and other aircraft.
The application of his expertise to medicine is particularly rare, said Michael Miller, professor of surgery and director of the division of plastic surgery at Ohio State.
The method, topological optimization, puts a computer to work to design the smallest structure needed to accommodate specific spatial boundaries and mechanical loads. The technique combines a series of mathematical equations with advanced 3-D imaging to produce a structure that takes into account both the space to be filled and space that must remain unoccupied to allow for such features as nasal passages and eyes.