Innovations in Treating Common Disease (photo by Barry Staver)

  By Cindy Foster, HSC Public Affairs
Dr. Jon D. Wagner (photo credit - Barry Staver)

Trauma to the face where the jaw takes a beating—be it from the impact of a car accident, gunshot or knife—is a significant source of injury among young men in New Mexico. Often, this type of injury requires multiple, delicate, intricate surgeries to repair, with a great deal riding on the success of such surgeries.

With 70 percent of human communication being non-verbal, injuries or surgical complications that can dismantle the muscles, nerves and bone of the face can have significant effects. The lower jaw – or mandible – must be able to withstand up to 2,000 pounds of pressure with each bite. If it is set or heals wrong in surgery not only can it impact the ability to eat, but also to speak or smile. These types of trauma can profoundly impact a young man’s career and future at the very beginning of adulthood.

Yet there have been remarkably few improvements in surgical hardware used in plastic surgery during the 20th century. “There should be a reason for using a screw besides the fact that it is available at the hardware store,” said Jon Wagner, MD, DDS, Associate Professor of Plastic Surgery. “But no one has ever really looked at fasteners in a systematic way to customize their use.”

Wagner and his colleague, plastic surgeon Bret Baack, MD, are leading a collaborative research effort with Sandia Laboratories, and the UNM School of Engineering’s Mechanical Engineering Department to bring surgery fasteners into the 21st century.

The primary question is how much fixation is actually needed with each type of surgery? Large screws holding down large plates across the jaw are strong but create more of a chance for nerve damage. They can’t easily be placed where needed which often means long, expensive surgeries that increase the risk of complications. Smaller hardware and screws mean smaller incisions but they may not hold to the bone under too much repetitive stress.

With another colleague, James Kelly, PhD, Professor of Surgery, Wagner quickly came to the conclusion that collaboration with UNM main campus was needed. “We realized we had something that could benefit both sides of the campus,” said John Wood, PhD, Director of the UNM Manufacturing Engineering Program.

Some groundwork was already underway. UNM surgeons have worked for several years with technology developed at Sandia Laboratories called “rapid prototyping” that can translate data collected from a CT scan into a low-cost plaster-of- Paris model within hours of an accident. The model allows them to “do surgery before surgery” and plot exactly how and where they will place fasteners needed to knit the bones back together. Such preplanning can shave two-to-six hours of OR time and thousands of dollars off surgery costs.

With the UNM engineers and engineering graduate students, the team has begun using a technology called Finite Element Modeling—the same technology that was used to investigate how the Space Shuttle Challenger exploded. In one current line of investigation, engineering graduate student Naresh S. Chaudhary has been testing the effects of different size screws and customized jig screw heads placed throughout the jaw. In another, engineering graduate student Scott Lovald is actually changing the shape of the plates traditionally used to span fractures and testing stressors.

“I’ve always been fascinated with complex systems and human bodies are very complex systems,” said Woods. “We know there are more opportunities for tangible interactions and research with the School of Medicine. It’s opening up new horizons on both sides of campus.”

“At the end of the day, it may well be that much of what we are doing now will still be the best approach for many surgeries,” said Wagner. “However, having said this, we are already finding new and exciting concepts in fastener and fixation design which will change surgical correction of maxillofacial injuries.”


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