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A Model Surgery: 3D Printing Key to Success

By: Ashley Berke Published: Mar 2, 2016

It was barely noticeable. The lump on seven-year-old Clubber’s head was camouflaged by the dog’s dark brindle fur. But owner Kerrie Tiedemann, a third-year Penn Vet student, spotted the hard bump back in June.

“We brought him to our vet, but they said it didn’t look like anything menacing,” said Nance Tiedemann, Kerrie’s mother.

Before surgery, the growth is a visible lump on Clubber's head.Over the next several months, Clubber appeared healthy, showing no signs – clinical or behavioral – of illness or pain. However, the lump above his right eye seemed to be growing, so the Tiedemanns brought Clubber to another veterinary practice near their home in Maryland for an MRI.

“They weren’t equipped with the tools to properly diagnose and treat the problem,” Kerrie said. “So they recommended we see a specialist.”

Kerrie and her mother Nance decided to make the trip to Philadelphia to see the experts at Penn Vet’s Ryan Hospital.

“There is so much interaction among the clinical services,” said Kerrie, based on firsthand experience as a student. “I knew that no matter what the problem was, they would be able to point us in the right direction.”  

An Unusual Diagnosis

Clubber was seen by Penn Vet’s Neurology service in late November for evaluation of the small, firm mass on the right side of his skull.

“I was really nervous to leave Clubber behind because he’s an anxious dog,” Nance said. “But when we came to Penn Vet, the frustration and nerves melted away. Clubber seemed comfortable, so I was comfortable.”

Neurology Resident Dr. Laura Krzykowski and the rest of the Neurology team reviewed the MRI taken in Maryland, which revealed an abnormal growth in between Clubber’s eyes and extending to the brain.

“The mass was not compressing the brain wall, but it was pressing against the skull and the sinuses,” explained Dr. Jonathan Wood, Neurology Resident. Clubber had no neurologic abnormalities, vision loss, or pain, but his owners wisely wanted to take action before the mass progressed.

A CT scan of Clubber's head shows the growth interrupting the white line of his skullThe first step was to obtain a bone biopsy of the mass. Unfortunately, some of the possible diagnoses included malignant cancers such as multilobular osteochondrosarcoma (MLO) or osteosarcoma. As they awaited the results of the biopsy, the Tiedemanns prepared for the worst..

“We expected to learn that Clubber had cancer, so we tried to give him the best time of his life,” Kerrie said. “My mom even started feeding him steak.”

But the pathology report, completed by Penn Vet’s Dr. Julie Engiles, came back with an unexpected diagnosis: a fibro-osseous proliferation, which is a non-neoplastic lesion, or growth. “It was a slightly unusual diagnosis,” said Wood, but not one unfamiliar to experts at Penn Vet.

A study by a group of clinicians from Penn Vet’s Dentistry, Imaging, and Pathology services was published in Veterinary Pathology in 2015, showing that several dogs with this diagnosis that underwent surgery lived disease-free during the duration of the study. This was good news for Clubber.

Though his mass was growing quickly, there was a surgical option to remove as much of the growth as possible from the skull.

A 3D rendering of a CT scan shows the bone growth on Clubber's skull.The Tiedemanns elected to proceed with surgery. “I don’t like to see animals suffer,” said Nance. “There was something we could do for Clubber, so we had to try.”

But this would not be an ordinary surgical procedure. A January 4th CT scan showed that the growth was now pressing against Clubber’s nose and eyes, explaining why Clubber had begun to snort and sneeze a few days earlier. 

Even though there was a surgical option, Wood knew it was a risky and complicated procedure that meant removing a large portion of the dog’s skull.

Due to the rapid growth of the mass, Wood knew there was only one way to help ensure a successful surgery, and that was to call PennDesign.

A Unique Collaboration

Penn Vet and PennDesign have worked together over the past two years to create 3D models that precisely replicate patient injuries and skull deformities. This would be the first time a model would be used prior to a surgery.

Using special software, Wood created a 3D file of Clubber’s CT scan, which he then sent to PennDesign’s Fabrication Lab. They created the 3D model the next day.

The PennDesign Fab Lab crew: Stephen Smeltzer, Dennis Pierattini, and Michael Stifel“We were in between semesters, so we were able to turn the model around quickly,” explained Stephen Smeltzer, Digital Fabrication Manager at PennDesign. “I feel lucky to have been in the position to help. Everything aligned perfectly.”

Smeltzer was aided by Dennis Pierattini, Manager of the Fabrication Lab; Michael Stifel, Assistant Manager of the Fabrication Lab; and Kaori Feldman, Digital Fabrication Technician.  

The eight-hour production process included creating the model out of gypsum powder, removing the residue, and coating the model with cyanoacrylate (super glue) to make it rigid. The end result was a 3D skull with bone-like characteristics, making it perfect for practicing a delicate surgical procedure that had very little room for error.

The 3D model of Clubber's skull fashioned by the PennDesign team. Dr. Wood used the white to plan the surgery and practice molding the titanium mesh.Wood was able to “operate” on the 3D skull, enabling him to create a roadmap for the surgery in advance. “It made a world of difference for us,” Wood said. “If we didn’t have the option to print and practice on the skull, I probably would not have recommended such an extensive surgery as an option.”

Because such a large portion of Clubber’s skull would need to be removed in surgery, Wood planned to use titanium mesh typically used in human brain surgery to replace the excised portion of the skull and to protect the brain. He and the surgical team were able to mold the mesh prior to surgery using the 3D model. “It worked during our practice sessions, so we were confident that it would work in the surgery,” Wood said.

A Complex Surgery

Prior to operating, Wood consulted with Penn Vet’s ophthalmologists, dental and oral surgeons, and orthopedic surgeons. The surgery would require very careful work around the nose, eyes, and brain.

Clubber was prepped for surgery on January 13. Wood and the eight-person surgical team removed a portion of his cranium, frontal sinus, and the orbits. Again, the 3D model proved to be imperative to success. “We referenced the model during surgery for intra-operative guidance,” Wood said.

A scene during Clubber's surgeryWood then screwed the titanium mesh into place, which had been contoured and cut in advance.

Given the size of the mass, a complete surgical excision was unlikely. But Wood removed as much of the diseased portion of Clubber’s skull as possible.

“We knew we were leaving something behind; there was no way to get everything out,” Wood explained. “But hopefully we’ve bought Clubber a lot of time.”

Following the six-and-a-half-hour surgery, Clubber recovered overnight in the Intensive Care Unit. He started eating the next day and recuperated remarkably well. He was able to blink and his face looked similar to his normal profile. Kerrie visited him every night.

Clubber poses with Dr. Jonathan Wood and Dr. Evelyn GalbanBefore discharging Clubber, Wood invited Smeltzer and his Fabrication Lab collaborators to meet the recovering dog.

“A lot of the time, we have a long waiting period before we can see our work come to fruition,” Smeltzer said. “To actually pet the patient that benefitted from our work within a week of creating the model was very, very special. Of all the things I’ve made or assisted with, it really took my breath away to look at the model and then see Clubber come out of the ICU. My heart skipped a beat.”

A Promising Future

Clubber was discharged on January 16 – just three days after surgery. “He is back to his rambunctious self,” Nance said. “When I tell people about the surgery and the 3D model and the titanium mesh, they are amazed. I tell everyone that it just wasn’t his time yet. And I’m going to be optimistic that it doesn’t return. But at least we can say we did everything we could.”

Clubber looking well after a check-up

For Kerrie, the experience was eye opening on another level. “In class we learn about good client communication, and I got to experience it on the client side,” she said. “Everyone did a really good job of telling us what was happening, step-by-step. I was really impressed with how transparent the vets were with us. It helped build a strong relationship and a lot of trust.”

Going forward, the teams at Penn Vet and PennDesign hope to collaborate even more using innovative 3D printing. “This technology helps us push the limits of what we can do,” said Dr. Evelyn Galban, Clinical Assistant Professor of Neurology and Neurosurgery. “This particular model was used in real-time, which was the most exciting part.”

“I hope that we can continue to help in the future,” Smeltzer said. “I wouldn’t hesitate to aid anyone at Penn.”

For the Tiedemanns, the partnership had a tremendous impact. “Our family is eternally grateful to Penn Vet,” said Nance. “Clubber was truly in the best hands possible.”

Read PennDesign's blog about the case.