OncoLog: MD Anderson's report to physicians about advances in cancer care and research.


From OncoLog, February 2011, Vol. 56, No. 2

Surgeons Use Computer-Generated Models for Jaw Reconstruction

By Bryan Tutt

Recent advances in technology have enabled surgeons to perform facial reconstruction with a degree of precision that was impossible just a few years ago.

Resection of head and neck tumors can leave patients permanently disfigured, especially if sections of bone must be removed along with the tumor. Because cancers of the head and neck often involve the mandible or the maxilla, reconstructive surgeons are constantly seeking new techniques to rebuild patients’ jaws to match the original as precisely as possible.

“Reconstructive surgery has come a long way in our lifetimes,” said Matthew Hanasono, M.D., an associate professor in the Department of Plastic Surgery at The University of Texas MD Anderson Cancer Center, who explained that the current technique for jaw reconstruction using tissue harvested from the patient’s leg was developed in the early 1980s. Since then, surgeons at MD Anderson and other institutions have worked to refine the technique. These efforts have led to an unusual collaboration between surgeons and engineers to create virtual and physical models of patients’ bones using software and tools adapted from the manufacturing industry.

Reconstructing the jaw

When head and neck surgeons have to remove part of a patient’s jaw bone to resect a tumor, the plastic surgeon’s ability to rebuild the jaw to match its former shape affects not only appearance but also functions such as eating and speech. Chronic pain in the temporomandibular joint also can result from an imperfectly aligned jaw.

The standard reconstruction technique involves harvesting a section of the fibula and any necessary skin, muscle, or fat from the patient’s leg. The surgeons cut the harvested section of bone into pieces, which are then formed together along a titanium plate, which the surgeons have bent to match the shape of the original mandible or maxilla as closely as possible. “This is where plastic surgery can become an art,” said Roman Skoracki, M.D., an associate professor in the Department of Plastic Surgery. Autologous tissue transplants, or free flap transfers, are used to rebuild the lining inside the mouth and/or the facial skin. All of this is done immediately following the tumor resection.

To complete the reconstruction, Dr. Skoracki said, “Our dental colleagues anchor osseointegrated implants to the new jaw bone. For all intents and purposes, these act like the patient’s natural teeth.”

Because the tibia is the main weight-bearing bone in the lower leg, the middle portion of the fibula can be removed without causing disability to the patient—Dr. Skoracki described the fibula as “a built-in spare part.” Patients who have jaw reconstruction using a fibula flap typically are able to resume walking within 5 days, eat solid food within 2 weeks, and resume normal activity within 3 months. However, recovery may take longer for patients receiving adjuvant chemotherapy or radiation therapy.

Limitations of reconstructive surgery

One area of concern for surgeons performing jaw reconstruction is the amount of time required for the surgery. When patients undergo resection of a tumor from the mandible or maxilla followed by reconstruction with autologous tissue, they are under general anesthesia for 10–12 hours. Dr. Skoracki said, “Our part of the surgery—harvesting the leg bone, reconstructing the jaw to the shape we want it to be, finding the appropriate donor blood vessels to use, setting the plate and tissue into place, resurfacing the inside of the mouth where it may be necessary, attaching the blood vessels under the microscope, and finally putting the external skin back together—takes 6–8 hours.”

Dr. Hanasono said, “If we can cut that time by a couple of hours, it benefits the patient in many ways, including lowering blood loss and risk of infection.”

In standard autologous tissue reconstruction, the titanium plate must be measured and bent to match the patient’s existing jaw bone. But for some patients, this is not possible. “Some patients have very distorted bones—from the tumor itself, from previous surgery, or from osteonecrosis from radiotherapy,” Dr. Skoracki said. “The challenge in reconstructing a jaw for these patients is that you can’t place the plate on the original bone to bend it—the ‘normal’ is not there.”

Borrowed technology

The difficulty in estimating the shape of the plate—and the resulting pain and loss of function for patients whose rebuilt jaws did not align perfectly—led surgeons to search for a more precise technique.

“We worked with a software design company to develop a modified version of computer-assisted design software, which is used in drafting and engineering, specifically for the craniofacial skeleton,” Dr. Skoracki said. The software creates a virtual replica of the patient’s anatomy from magnetic resonance imaging (MRI) or computed tomography (CT) images of the patient’s jaw. The software helps surgeons to plan the reconstruction by creating the exact shape of the jaw that will be resected. The surgeons can then cut a virtual fibula to the exact angles that will optimize bone apposition, further helping plan the surgery.

To take this planning aid from the computer screen to the physical world, physicians at MD Anderson, working with another design company, developed plastic cutting guides that can be snapped in place on the fibula so that it can be cut to the exact lengths and angles defined by the virtual plan. These cutting guides are created using a three-dimensional printer—a technology used in the manufacturing industry to make prototypes—which prints the starch or polymer model layer by layer. The printer can also produce a three-dimensional replica of a patient’s jaw.

“It’s wonderful to have these models because we have an exact template of what the ideal would be,” Dr. Skoracki said. “We can bend plates on the model, which allows us to be more exact in our reconstruction. We can actually perform surgery on these acrylic or starch models to rehearse.”

In addition to improving the accuracy of reconstruction, Dr. Hanasono said that the models reduce the time required for surgery because the surgeons can bend the titanium plate to the correct shape before surgery.

Accessible technology

Surgeons at MD Anderson outsource the virtual modeling and three-dimensional printing to a private company. The surgeons send the patient’s MRI or CT images to engineers at the company and discuss the case with them in videoconferences. The engineers then create the virtual models, and if needed, physical models and cutting guides are printed and shipped.

Because the private contractor can create these models from imaging studies, the technology is available to surgeons at almost any institution. Dr. Skoracki said the models can be especially beneficial to surgeons who perform only one or two jaw reconstructions per year. “This technology helps the surgeon plan the surgery and execute it more precisely,” he said.

Dr. Hanasono said that surgeons at MD Anderson do more jaw reconstructions using autologous tissues than any hospital in the United States, but the models are used only for the most complicated cases—about 12 per year.

Dr. Skoracki added, “We use the whole gamut of these technologies for those patients who have very large tumors that prevent us from doing the measurements necessary for the usual method of reconstruction.”

Dr. Hanasono pointed out that the full potential of the modeling technology has not yet been realized. “This technology has been in development for 8–10 years, but its current form has only been in use about 3 years,” he said. “The technology has implications not only for cancer but for all types of reconstruction, including reconstruction in trauma patients.”

Body Image Therapy

Many cancer patients—especially those with tumors of the head and neck—face the possibility of disfigurement and functional difficulties stemming from the disease as well as its treatments.

One source of help for these patients is MD Anderson’s Body Image Therapy Program, which provides psychosocial services to patients before and after reconstructive surgery. The program, led by Michelle Cororve Fingeret, Ph.D., an assistant professor in the Department of Behavioral Science with joint appointments in the Departments of Head and Neck Surgery and Plastic Surgery, was launched in 2008.

“Our plastic surgeons can do amazing things, but there are bounds of reality that we have to work within,” Dr. Fingeret said. Many of her patients have disabilities related to cancer or cancer treatment that make it difficult to speak or eat. While other therapists help these patients with functional rehabilitation, Dr. Fingeret helps them gain the confidence to go out in public and do the activities they used to enjoy doing.

“The basis of this program is to try to normalize and validate patients’ body image concerns,” she said. “Patients often feel that they are the only one experiencing these things. To have somebody come in and tell them they are not alone—that in itself really helps them feel more supported and encouraged to get back to living their lives.”

Dr. Fingeret works as part of the multidisciplinary treatment team in the Head and Neck Center, where she counsels patients regardless of whether they are having reconstructive treatment. She helps some patients deal with anxiety before or during reconstructive procedures—some of which require multiple surgeries over several months—and helps others cope with their situation after the completion of their cancer treatment and reconstructive surgery. “When the plastic surgeons tell patients that no further improvement is possible—that’s sometimes when the body image issues develop for patients who have been holding out hope that things would get better,” she said.

Most of the program’s patients are referred by the Center for Reconstructive Surgery; about half are being treated for head or neck cancer and half for breast cancer.

It is not uncommon for patients who have had surgery for breast cancer, even though the absence of a breast is usually not visible when the patient is dressed, to face the same issues of social isolation or anxiety about body image experienced by survivors of head and neck cancer. “There are things we can do to target the way patients are thinking about things,” Dr. Fingeret said, “but we’ll also get them to increase the number of activities they participate in—things they find pleasurable.”

Dr. Fingeret is also doing research to determine the nature and extent of the concern patients have about body image. “We expect all of our patients, to some degree, to have body image concerns,” she said. “Body image concerns are normal.”

For more information, contact Dr. Matthew Hanasono at 713-794-1247 or mhanasono@mdanderson.org or Dr. Roman Skoracki at 713-794-1247 or rjskoracki@mdanderson.org.


Home/Current Issue | Previous Issues | Articles by Topic | Patient Education
About Oncolog | Contact OncoLog | Sign Up for E-mail Alerts

©2013 The University of Texas MD Anderson Cancer Center
1515 Holcombe Blvd., Houston, TX 77030
1-877-MDA-6789 (USA) / 1-713-792-3245  
 Patient Referral    Legal Statements    Privacy Policy