Surgeons conducting face transplantation procedures have been given a new tool by researchers who are combining CT scans with 3D printing technology to create life-size models that duplicate patients' heads.
The replicas let surgeons see existing bone grafts, any metal plates that have been implanted and the underlying bone structure of the skull, which improves their planning of the surgical procedure and shortens the time the patient must spend under the knife, researchers say.
"This is a complex surgery and its success is dependent on surgical planning," says radiologist Dr. Frank J. Rybicki of Brigham and Women's Hospital in Boston, where the first U.S. full-face transplant was performed in 2011. "Our study demonstrated that if you use this model and hold the skull in your hand, there is no better way to plan the procedure."
A 3D model of the patient's head is important for the surgeon contemplating a face transplant because the procedure is often the last in a long string of surgeries and operations that may have left metal plates, bone grafts and surgical screws that the new face must fit around perfectly.
"Typically, by the time they come to us, they've had 20 or 30 surgeries already, just to save their lives," Rybicki says.
Knowing where all the previous surgeries took place and their changes to the skull allows the surgery, which can last up to 25 hours, go much more quickly and smoothly, he says.
A 3D model is particularly helpful in that case of understanding the underlying soft tissue, difficult to visualize by any other means, the researchers say.
The technique will also improve the outcome in less dramatic kinds of facial reconstruction, doctors say, such as replacement for a destroyed jaw.
In such a procedure, surgeons usually craft a new jawbone using a piece of rib or leg bone taken from the patient, but since those are fairly straight bones it is often tricky to cut a curved piece for a perfect fit as a new jaw.
A 3D printed skull allows for a more precise cut and fit of the bone, says Dr. Edward Caterson, a plastic surgeon at Brigham and Women's Hospital who is part of the face transplant team.
The printed models can be taken directly into the operating theater to help surgeons double-check the structure and anatomy of a patient's face during the transplant procedure.
"You can spin, rotate and scroll through as many CT images as you want but there's no substitute for having the real thing in your hand," Rybicki says. "The ability to work with the model gives you an unprecedented level of reassurance and confidence in the procedure."
