The procedure that was performed at NYU Langone Medical
Center on February 19, 2011, was nothing short of
spectacular, even to an advanced team of surgeons who had
spent months planning the surgery and years envisioning it.
The 29-year-old patient, Maria Palma, was diagnosed with
ameloblastoma, a benign tumor that forms from the precursor
cells of teeth. Such tumors can become dangerously large
but typically do not spread to other parts of the body.
This young woman's tumor was in the lower anterior portion
of the jaw-one of the hardest parts to reconstruct-and
involved most of her lower teeth.
David Hirsch, DDS, MD, FACS, oral and maxillofacial and
head and neck surgeon, has devoted himself over the past
five years to perfecting the computer-aided technology that
enabled this surgery to take place, significantly reducing
the time the patient spent in surgery as well as the
cosmetic repercussions of the procedure. Thanks to the
passion of Dr. Hirsch and a highly skilled team, a process
that used to require three surgeries over the course of a
year can now be done in a day. So it was that on February
19, after the lower half of the patient's jaw was removed
and replaced with bone from the leg, and dental implants
were placed in the new bone, she woke up with a set of
functional teeth-the first time this operation has been
accomplished in one surgical session in the United
States.
An ameloblastoma is generally discovered on a routine
X-ray, which was the case for this young woman. In the
past, the surgery to remove the tumor and replace the
affected jaw-bone with bone from the patient's leg was
extremely long and almost always disfiguring. Calculations
of how much leg bone was needed and its subsequent removal
could not be done until the jaw bone had been removed, all
with the patient under anesthesia.
Over the past five years, Dr. Hirsch, who serves on the
faculties of NYU College of Dentistry and NYU Langone
Medical Center, working with Jamie Levine, MD, plastic and
reconstructive microsurgeon and chief of microsurgery at
NYU, and Lawrence E. Brecht, DDS, director of dental
services and craniofacial prosthetics at the Institute of
Reconstructive Plastic Surgery of NYU Langone Medical
Center, and a member of the NYUCD faculty, has
revolutionized the process for removing tumors by using
computer-aided imaging to plan the entire surgery in
advance. Recognizing the potential for such imaging in
maxillofacial surgery, Dr. Hirsch began working with both a
software company and a manufacturer that, together, created
blueprints and actual models, enabling the surgeries on
both the jaw and the leg bone to be planned precisely in
advance. This planning allowed surgical teams to operate
simultaneously on the jaw and leg, reducing the length of
surgery from the usual 20 to only 8 hours.
Prior to the February surgery, Dr. Hirsch and Dr. Levine
had performed some 40 mandibular reconstructions using the
computer-aided technique. They continually refined the
procedure, on both the computer and in the operating room.
Yet, patients who underwent the much-improved surgery still
needed to return in 8 to 12 weeks for a second operation to
receive dental implants in their newly fashioned jawbone.
It took another four to five months before prosthetic teeth
could be made, because of concern as to whether the dental
implants, set into the leg bone, would settle in the proper
position. The entire process could take well over a
year.
"Imagine what we could do for patients, psychologically,
if they could leave the operating room with teeth on the
same day," Dr. Hirsch asked himself. "That's what led us to
the next steps."
The team studied whether dental implants-titanium
cylinders that are drilled into bone-could be surgically
placed with the needed precision at the same time as the
transfer of leg bone, and determined that they could. This
development eliminated the need for a second surgery to
place the implants. The extremely delicate operation would
require the surgeon to place the implants into the leg bone
before it was detached from its blood supply.
A New Era of Microsurgery
"Historically," Dr. Levine says, "it was rare for a
person who needed jaw reconstruction to receive dental
rehabilitation. People were left with serious deformities.
The era of microsurgery, beginning in the 1970s, led to
facial-bone replacement from other parts of the body. Even
so, full dental reconstruction, enabling a patient to chew
and function maximally, was not even conceived of as
recently as the '70s or '80s. Now we can plan these
surgeries much more accurately and ensure a much better
quality of life for our patients."
Planning for the February 19 surgery began a month in
advance. All of the doctors and their support staff met
together with the patient to explain each step in the
surgical and recovery processes-a step that, in itself,
might not have been done in a less patient-centered era.
Once Dr. Hirsch decided where to make the cuts around the
tumor in the patient's jawbone, Dr. Brecht's role was to
figure out exactly where the implants and new teeth needed
to be placed. Finely sliced CT scans of the patient's face
and leg were then formatted into digital three-dimensional
images. Computer technicians in Golden, Colorado, turned
the digital images into a physical model. The same company
produced a set of cutting guides, which Dr. Hirsch humbly
likens to furniture-assembly instructions. A second set of
models was made so that the surgery could actually be
performed on the model to pretest the guides. Teeth and
ideal implant locations were constructed in Reno, Nevada,
also using the digital plan. On the day of the surgery,
cuts were made in both the jaw and the leg bone according
to the computer-generated cutting guides.
"What David Hirsch has done, through his technological
interest and expertise, is to find the common bond that
brings together not only various specialties but the
various parts of the body to get the superb results they
achieved," says Robert Glickman, DMD, professor and chair
of the Department of Oral and Maxillofacial Surgery at NYU
College of Dentistry.
Dr. Glickman adds that computer-aided surgery has
existed for some time, but in the past it was not precise
enough for maxillofacial surgery. Dr. Hirsch pushed the
software developers to create a model so precise that it
mirrored the actual surgery.
When it came time to perform the surgery, Dr. Levine
removed about 15 centimeters of bone in the middle portion
of the fibula, leaving it attached to the circulation that
provides blood flow from the peroneal blood vessels. He
attached the pre-planned devices that would help guide the
surgeon's cuts and ensure that the bone would bend
precisely to the jaw. With the devices still attached to
the leg bone, Dr. Hirsch placed the dental implants and
then Dr. Brecht snapped the prosthetic teeth into position.
Then, Dr. Levine, using a microscope and needles the size
of a human hair, attached the peroneal vessels to the
vessels of the neck. The fibula construct, including
implants and the fixed prosthesis, was then connected to
the patient's remaining mandible using titanium plates.
Damage to the leg is minimal, he notes, because the fibula
bears only three percent of the body's weight, and patients
can walk soon after.
"The beauty of this story is that no one part could have
happened without a very close-knit working team of
specialists who really understand what each person on the
team does, their skill, the risks that others are assuming,
and the orchestration," says Dr. Levine.
Dr. Hirsch concurs that it took an exceptional
interdisciplinary team effort to conduct this surgery
because so many things had to go perfectly. "With the
computer-generated blueprint, everything turned out right,"
he says.
A Winning Combination of Skills
Dr. Brecht adds that the procedure could not have
happened without the combined world-class skills found at
NYU in oral and maxillofacial surgery, microsurgery, and
maxillofacial prosthodontics. In a prior era, he joined the
team later in the process, and sometimes he wished that the
space for implants had been made in a different location.
Now that his expertise is incorporated from the start,
implants can be placed exactly where he wants them.
The Institute of Reconstructive Plastic Surgery at NYU,
where Dr. Brecht serves as director of dental services, was
founded after World War II by plastic surgeons and dentists
who had routinely worked together on maxillofacial units in
the European theater of war. When they came back to the
United States, they wanted to continue their collaborations
for ordinary surgical patients.
"What's unique about the institute is that its people
forged a working environment where teams really understand
one another and how their skill sets work in unison," Dr.
Brecht says.
Dr. Glickman's pride in the team's work is evident.
"David Hirsch is an extraordinarily well-trained surgeon.
In Jamie Levine, you have one of the finest reconstructive
plastic surgeons in the United States. And Larry Brecht is
one of the best maxillofacial prosthodontists-of which
there are very few. It would be very hard to get this level
of expertise anywhere else."
Most important, the patient is making an exceptional
recovery, having left the hospital after merely seven days.
Despite some facial swelling, her teeth looked natural, she
can smile, and she is able to eat using her new
prosthesis.
Dr. Levine compares the groundbreaking surgery to
building the world's first skyscraper. All of the
components had to have been invented first, and then it was
a matter of someone having the vision to put them all
together.
"We've been evolving toward this ability for some time.
But getting there is truly unique," he says.