Cleft Palate Practice, Pre-Surgery - New York Times
August 2, 2005
Cleft Palate Practice, Pre-Surgery
By AMANDA SCHAFFER
On a computer screen hovers a three-dimensional image, the face of a boy with a cleft lip and palate.
Using a mouse, a visitor to New York University's Virtual Surgery Research Laboratory can navigate
through the boy's mouth, as if it were a landscape in a video game, passing under and through brightly
colored layers of tissue, muscle and cartilage. Patches of transparency highlight underlying ivory bone.
The images are part of a highly accurate animated simulation of cleft lip and palate surgery that will
eventually allow surgeons, medical residents and students to practice reconstructive procedures in real
time, in a 3-D environment. Users will be able to mark incisions in virtual skin, draw back flaps to
reveal underlying tissue layers and then manipulate these layers from different perspectives to repair a
virtual cleft.
Cleft lip and cleft palate are birth defects characterized by the failure of tissue of the lip or mouth to
close properly during fetal development. If left untreated, clefts can cause problems with speech, eating
or breathing, as well as social difficulties for children who have the condition.
Dr. Court B. Cutting, the cleft lip and palate surgeon who heads the project, said he envisioned groups of
students, connected by the Internet or sitting together, taking turns with the controls to complete the
virtual surgery.
He also imagines using the computer program to record the distinctive techniques of world-class
surgeons, thus giving students an opportunity to interact with them directly.
"We get various surgical experts to play the game," Dr. Cutting said. "We record how they play the
game, then we play it back" so the students can make alterations and learn from their mistakes.
Aaron Oliker, a computer programmer and 3-D animator who has worked on the project since 1999, said
the simulation was a result of the popularity of video games, which has caused graphics technology to
become "much cheaper and more powerful."
The simulation program, which the N.Y.U. team plans to complete in the next couple of years, is
financed by Smile Train, an international charity that helps children with unrepaired clefts, and it
represents the second phase of a continuing collaboration.
Executives of Smile Train first approached Dr. Cutting in 1999 and asked him to develop a set of
instructional CD's for physicians in the developing world.
Various charities send American and European doctors abroad for a few weeks at a time to perform cleft
lip and palate surgeries. But only a relatively small number of children are able to receive treatment this
way. Smile Train decided to focus on training regional doctors in the latest techniques, using a
combination of 3-D animation and intraoperative video.
"One of our missions is to empower local surgeons," said DeLois Greenwood, vice president of Smile
Train.
Dr. Cutting, who served as a surgeon in Vietnam and elsewhere, was sympathetic to Smile Train's
approach. He was also skilled with computers, having spent 25 years doing computer graphics-related
research.
"I just sort of naïvely said, well sure, let's use animation programs," Dr. Cutting said. "They're very well
developed now, and we'll just illustrate surgery."
He hired Mr. Oliker and Julie Haring, another animator, to participate in the project.
The team then developed a detailed three-dimensional model of a cleft lip and palate, using M.R.I. and
CT scans of two Chinese children with clefts, 8-year-old Shan Furong and 11-year-old Yi Yun, before
and after they underwent surgery at N.Y.U. Medical Center.
Additional visual data was gathered from the Visible Human Project, a project financed by the National
Institutes of Health to create detailed, volumetric models of adult anatomy.
The resulting CD's illustrate cleft lip and palate surgery from a variety of vantage points. Some of them,
deep in the mouth, would be difficult to capture with a regular video camera. The animation also allows
the viewer to see though anatomical layers, a feature useful in understanding how underlying structures
like nasal cartilage are repositioned during surgery.
"They are extremely good teaching modalities," said Dr. Hirji Adenwalla, head of the Charles Pinto
center for Cleft Lip and Palate at Jubilee Mission Medical College in India. "We make it a point to show
them to every trainee who comes to us."
Smile Train, which also pays for the surgeries, has distributed over 10,000 copies of the CD's in 55
countries, including India and China.
Dr. Richard Satava, professor of Surgery at the University of Washington Medical Center and a pioneer
in the medical uses of virtual reality and surgical simulation, said Dr. Cutting's work was
groundbreaking.
"Most people use a generic model," Dr. Satava said. "The thing he's done is taken the idea and applied it
to the images of very specific patients," namely the two Chinese children.
Dr. Satava predicted that some-day physicians would be able to create dynamic models of individual
patients, planning and practicing surgeries on a computer before heading into the operating room.
These models would be particularly useful for reconstructive operations because they would allow
doctors to envision not only how tissues will be sewn together but also how a part of the body like an
arm or a hand will move.
In developing the simulation for cleft lip and palate surgery, Dr. Cutting's team has focused on defining
and capturing the dynamic behavior of skin and other tissues with a greater accuracy.
In addition to modeling cleft lip and palate, Dr. Cutting's team is studying the physical properties of
breast tissue, using a machine that stretches material to show stress-strain curves. The goal is to build an
animated model that would prove useful to reconstructive surgeons.
Dr. Cutting is also interested in working on a virtual face, a project of potential interest to the military
because a large number of casualties in Iraq and elsewhere involve facial damage.
The field of virtual surgery is growing rapidly, with researchers focused variously on simulation, tissue
modeling and haptics, or the science of incorporating tactile feedback into user-computer interfaces. The
potential applications are broad, experts say, and could some-day cause a sea change in how surgeons
are trained and how research is conducted.
"I was trained in inner-city emergency rooms," Dr. Cutting said. "That's how a surgeon gets experience."
But, he added, if every surgeon in training could practice on a simulator before taking the knife to a
living patient, it would be a great improvement.
