Researchers at the University of Illinois at Urbana-Champaign and the Ohio State University Medical Center have shown that engineering design methods could be used to craft custom bone replacement implants for people in need of facial reconstruction.
The interdisciplinary research, whose results were published in the Proceedings of the National Academy of Sciences in 2010, could mean so much to patients in need of facial reconstruction. It involved the use of a technique termed topology optimization. This method has the potential to remove or reduce trade-off between form and function.
Reconstructive surgery may be essential for people with facial bone loss, be it as a result of injury or illness. This procedure, however, can be rather thorny. A surgeon will not only need to restore from but also ensure the preservation of function. There is not always a guarantee of both.
Typically, plastic surgeons harvest bone from another part of a patient’s body to make a replacement for the missing skull bone. However, differences in structure could result in facial distortion or impaired function. The speech, chewing, swallowing, or even breathing abilities of a patient may become impaired as a result.
The approach used in the research showed the potential to improve outcomes of facial reconstruction surgery.
“It tells you where to put material and where to create holes,” said Glaucio Paulino, a professor of civil and environmental engineering at the University of Illinois. “Essentially, the technique allows engineers to find the best solution that satisfies design requirements and constraints.”
The engineering technique
Topology optimization involves extensive use of 3D modeling for the design of structures that provide support for loads. Engineers commonly use it when forming structures, such as high-rise buildings and car parts.
As used in this research, the technique provides an interdisciplinary framework. It brings into one concept from diverse fields, including mechanics, numerical methods, computations, biology, and medicine. It makes it possible to have bone replacements optimized to the needs of individual patients.
The researchers started the process of making the tissue-engineered bone replacements by constructing a patient’s detailed 3D computer model. According to an injury and missing bone portions, they stipulate a design domain. Next, they create a custom-made structure using a series of algorithms, taking form and function into consideration.
They go further to model the process of inserting the engineered bone and the appearance of the patient after it would look like.
Paulino said this technique would enable physicians to “explore surgical alternatives and to design a patient-specific bone replacement.” Perfect designs that both restore form and support function may be available to patients as a result.
Work to continue
According to Paulino, topology optimization appeared well suited for facial reconstruction. The Donald Biggar Willet Professor of Engineering suggested that the technique could be perfect for procedures involving the mid-face. He described the area as the “most complicated” of the human skeleton.
Reconstructing the mid-face is a difficult task due to it having small, delicate bones. There is also a high risk of bacterial infection when procedures are carried out around the region.
The researchers successfully showed the potential usefulness of the technique, using a variety of facial bone replacement models. They hinted at interest in exploring other potential uses of the method.
“The technique has the potential to pave the way toward the development of tissue engineering methods to create custom fabricated living bone replacements in optimum shapes and amounts,” Paulino said.
The civil and environmental engineering professor expected to be able to develop scaffolds for tissue engineering. Success in that aspect could enable the translation of their designs to real bones.