Model Approach to Cleft Surgery
Cleft lip and cleft palate are the most common birth defects in the U.S., affecting 1 in 940 and 1 in 1,574 children, respectively. Surgeons are able to fix these problems by stitching together the soft tissues of the lip and grafting bone to fill in the gaps. Because these procedures are usually done when an infant is weeks or months old, scarring of the soft tissues is an inevitable part of the healing process, and more surgeries are often needed.
“What tends to happen with these patients is that as a child gets older, the repair may not look as good because of the scarring,” says Carroll Ann Trotman, professor and chair of orthodontics at Tufts School of Dental Medicine. “The result varies from patient to patient,” because their facial features change shape as they grow. The challenges go beyond aesthetics—some kids cannot move the facial soft tissues when eating, smiling or speaking, for instance.
Using motion-capture technology similar to that used in animated films and video games, Trotman has developed an approach designed to improve the way surgeons treat these patients and evaluate outcomes by providing a more objective way to measure soft tissue movement and facial structure than is currently available.
With this technique, facial movements can be modeled in three dimensions, both at rest and in motion. “Usually surgeons judge the extent of the problem by looking at the patient,” Trotman says. “The approach that we have developed adds an objective component to the surgeon’s subjective assessment.”
Three-dimensional modeling can help enhance, not supplant, doctors’ intuitive sense of how to go about these repairs, Trotman says.
With funding from the National Institute of Dental and Craniofacial Research, Trotman and surgeons from the University of North Carolina-Chapel Hill, Wake Forest Baptist Health Craniofacial Center, Boston Children’s Hospital and Massachusetts General Hospital began a clinical trial in November to assess how surgeons integrate the 3-D modeling technique when making decisions and planning treatments for surgeries to repair and replace lips.
After interviewing the doctors about their initial approach to the surgery, the researchers will show them static and animated 3-D models to determine whether and how they modify their surgeries. “We’ll do an analysis of how the treatment plan is modified in each step of the evaluation to see if this really does make a difference,” Trotman says.
In a preliminary study of 21 patients published in the Cleft-Palate Craniofacial Journal in November 2013, Trotman and colleagues at the University of North Carolina School of Dentistry reported that surgeons who used the 3-D modeling changed their initial treatment plan for a significant number of the patients. Moreover, using these same patient data, Trotman and her collaborators were able to demonstrate that surgeons exhibited significant bias in their judgments about the surgical outcome for patients, and this bias led to disagreements about the outcomes. The findings were recognized as the best research abstract by the American Association of Oral and Maxillofacial Surgeons at last year’s International Association for Dental Research conference.
That’s a strong indication that 3-D modeling can help enhance, not supplant, doctors’ intuitive sense of how to go about these repairs, Trotman says. “You can’t do this without looking at the patients, so subjective information is very important. What we want to do is improve the evidence base available for surgeons to plan their treatment—thus, adding the objective components.”
Michael Blanding is a freelance writer based in Boston.
This article first appeared in the Winter 2016 issue of Tufts Dental Medicine magazine.