Father, son benefit from jaw reconstruction guided by 3D virtual planningJul. 21, 2021, 2:29 PM
by Jill Clendening
A middle school basketball game set off a long, painful journey for Mt. Juliet resident Jeremy Kerr, 49, that ended in 2019 when he had orthognathic, or corrective, jaw surgery at Vanderbilt University Medical Center to address both an underbite and crossbite.
“After someone shot the ball, another player jumped first and got the rebound but elbowed me in the jaw as I was jumping up,” he said. “There was a loud pop, and everybody heard it. The next morning, my jaw was stuck halfway open. It was alarming.”
His jaw unlocked the next day without intervention, but the incident marked the beginning of more than three decades of popping, accidental cheek-biting, periodic jaw locking, and ultimately pain. The hoops injury likely contributed to one side of his lower jaw growing longer than the other, but genetics also played a role in his underbite and crossbite.
Several times, Kerr investigated what might be involved in repairing his jaw. He was put off by proposed surgeries involving the joint itself, by external fixator hardware he was told he’d wear for weeks after surgery, and by others’ stories of multiple surgeries to correct a jaw malformation.
“None of these solutions set well with me,” he said. “I decided I might just wait until the technology got better.”
Ironically, it was his son Tyler, who struggled with an even more pronounced underbite and crossbite, who got his jaw malformations corrected first.
“My son and I were initially going to go through the surgeries together, but I chickened out at the last minute,” Kerr laughed. “After I saw the great result my son had, I decided to go ahead. I’m glad I did. I now have no popping, no clicking, no continually biting my jaw. I don’t flinch, and I don’t even think about it when I’m eating now.”
Tyler was nearing high school graduation, and he didn’t want to go to college with a malfunctioning jaw. And he didn’t even realize how badly it affected his self-esteem until after it was fixed.
“I can laugh about it now, but when it was happening, it wasn’t funny to me,” he said. “I was insecure eating around friends because the way I had to eat was kind of weird. Pasta, I was cool with. A sandwich, I could finesse. Pizza, my favorite food, was a no, because if God’s scissors don’t meet, you’re not going to be biting off much of anything.”
The Kerrs were referred to Sam McKenna, MD, DDS, chair of the Department of Oral and Maxillofacial Surgery, as candidates for orthognathic surgery.
The surgery involves moving, lengthening or shortening the bones of the upper and lower jaw to correct alignment of the jaws and teeth and improve facial appearance. Surgical jaw corrections can also reduce chronic pain, improve speech, improve oral health and reduce the severity of obstructive sleep apnea.
Surgical candidates need to have reached skeletal maturity, meaning their bones are no longer growing; this is at around age 15-16 for girls and age 18-19 for boys. Post-surgical recovery varies, with patients typically hospitalized overnight as pain and swelling are closely managed. Having nursing staff at both Vanderbilt University Adult Hospital and Monroe Carell Jr. Children’s Hospital at Vanderbilt who are well-versed in the care of orthognathic surgery patients is a definite benefit, McKenna said.
Tyler’s surgical journey began with images of his skull taken with a Cone Beam CT scanner, which minimizes radiation exposure. Then, a vendor specializing in digital diagnostic and treatment imagery transformed the images into a 3D digital CT.
McKenna could then clearly view how Tyler’s entire jaw was shaped and how it related to his bite.
“This technology that allows us to plan surgeries in a virtual platform has really revolutionized the management of these deformities,” McKenna said. “The basis for that planning is, of course, still our examination of the patient, assessment of the deformity and making various measurements. But the three-dimensional CT allows us to sit at a computer screen and manipulate the bones in a very analytic and precise way.
“We can, for example, digitally move the maxilla (upper jaw) forward or move it vertically. Whatever we perceive as being their needs in order to correct the deformity, we can do. After we virtually manipulate the upper jaw and the lower jaw during a planning session, we establish the bite we want to achieve in the operating room. A surgical template based on the virtual planning is created using a 3D printer that we take to the operating room. That template allows us to achieve in the OR exactly what we’ve mapped out during the virtual planning.”
Prior to having this capability, McKenna and other Oral and Maxillofacial Surgery faculty and residents spent evenings and weekends in the lab making plaster models of patients’ jaws. The plaster would be mounted onto a device called an articulator, which allowed them to manually move the upper and lower jaw models to plan surgeries.
“We always approached the surgeries in a very analytical way, but it was limited by the ability to know how much we’re actually moving that plaster cast in space,” McKenna said. “With the ability to do this virtually using the 3D CT scan, it really satisfied our long-standing desire to do this as analytically as possible, but with much greater accuracy.”
Because the virtual planning shows the jaw in relation to the rest of the skull’s bones, there are few surprises in the OR, said McKenna, who estimates he now uses 3D virtual planning for around 80% of his surgeries.
Today, Tyler’s confidence has grown tremendously, and he’s attending college without anxiety about his jaw and face.
“It’s weird to realize now there was a time of my life where I really did think, ‘How am I going to eat this meal or is this going to be a disaster?’ Before, when I ate, I would probably bite myself four times a week. Now, that happens maybe once a month. And I have pizza in the oven right now.”
As for the elder Kerr, he’s grateful that the right technology in the hands of a skilled surgical team came together to finally give him a jaw that no longer malfunctions.
“The recovery was much easier than I expected,” Kerr said. “Now I think, ‘Man, why did I wait so long?’”