Researchers including one of Indian-origin have developed a new technique combining conventional medical imaging with 3-D modelling methods that could offer new hope to victims of serious facial injuries.
In case of face transplantation, facial tissue from a donor is transferred to reconstruct the defect, restore essential life-sustaining functions like breathing, chewing and speaking and, above all, re-establish normal human appearance.
“This surgery is for patients with devastating injuries to the face, who have lost their ability to smell, eat and engage socially and have no other conventional treatment options,” Vijay S. Gorantla, administrative medical director of the Reconstructive Transplantation Program at UPMC, said.
Medical imaging plays a major role in the entire spectrum of face transplantation, ranging from patient selection, donor and recipient surgical planning, and postoperative assessment of returning motor and sensory function.
Face transplantation is a lengthy, complicated procedure that involves reconstruction of multiple tissues like skin, muscle, blood vessels, nerves and bone by a team of surgeons.
By combining information from multiple imaging exams and creating a sophisticated 3-D computer model, the researchers were better able to assess the facial structure and contours, the underlying bone, muscles, nerves and vessels, as well as the extent of damage.
Using sophisticated computer-modelling software, lead researcher by Darren M. Smith and Gorantla, along with Joseph Losee, M.D., integrated information from 3-D CT, CT angiography, MRI and high-definition tractography to create a 3-D model of the patient”s head and neck anatomy.
The same type of modelling technology is often used in movies to animate computer-generated characters with detailed three-dimensional human features and realistic expressions.
“We have integrated data from multiple imaging sources into a single 3-D representation that allows for real-time user interaction and modification,” Smith said.
“In assessing eligibility for this procedure, it is critical to understand whether the patient has enough blood vessels and bone structure to support new facial tissue. This 3-D modelling helps us customize the procedure to the patient’s individual anatomy so that the donor tissue will fit like a puzzle piece onto the patient’s face,” he said.
Using computer modeling, the team also overlaid the patient model with a polygon mesh of a generic human face and then customized it to the recipient facial anatomy.
According to Smith, the ability to manipulate this 3-D facial envelope over the residual face model allows the entire surgical team to participate in planning exactly where bone, blood vessel and nerves will be cut and connected, as well as to evaluate the outcomes of reconstructive transplantation, including nerve regeneration within the transplanted facial tissue.
“The goal of face transplantation is not just structural,” Gorantla said.
“It is about restoring function, so that patients are once again able to chew their food, smile and regain the most important aspect of a normal face – to look human,” he added.
The study was recently presented at the annual meeting of the Radiological Society of North America.