Dinsmore and the Children’s Hospital of Orange County Show Value of Patient-Specific 3D Printed Tibia Model

November 1, 2017 by Rich Wetzel 3D Printing Medical 3D Printing

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A 3D printed anatomical model assisted in recent successful surgery on eighteen-year-old Moises Campos. In order to help surgeons better prepare for the complex operation, the Children’s Hospital of Orange County (CHOC) recently teamed up with Dinsmore Inc., a 3D printing company from Irvine, California, to 3D print a full-scale model of Campos’ tibia based off his CT scan. Using 3D printing as a means to simulate difficult procedures is becoming more common for surgeons around the world, and it’s only possible because new advancements have increased the speed and accuracy of the technology.

Campos suffered a tibial tubercle fracture during his youth, which resulted in a growth arrest below his kneecap and a deformity of his tibia. This type of deformity caused difficulty in daily activities such as walking or running, and significantly increased the risk of early onset arthritis. In order to correct it, surgeons needed to make cuts to the bone and carefully move it back to the normal position. Due to the complexity of the surgery, pediatric orthopedic surgeon Dr. Afshin Aminian, Medical Director of the CHOC Children’s Orthopedic Institute, reached out to Dinsmore to request assistance for creating a life-size 3D model of Campos’ tibia. Relying on an intra-operative assessment during the surgery would have risked the chances of a successful outcome, so having the opportunity to study an exact replica of Campos’ deformed tibia was invaluable for the surgical team. It allowed them to visualize their moves, plan their cuts, and keep the patient and his family informed on exactly what they were going to do during the operation.

Dinsmore’s engineers used data from the CT scan to convert the tibia model into a digital file compatible for 3D printing.

Jay Dinsmore, President and Founder of Dinsmore Inc., described his experience working on the unique project with the CHOC team of surgeons:

“We were excited to take on this project and hopefully have a positive impact on Moises’ surgery. We printed several models with the data from a series of CT scans over a few weeks. The front-end work of ensuring data integrity was the most time-intensive step of the process, but also the most important. At Dinsmore, we are proud to offer our customers design for prototyping as a service to ensure that their data and files are prepared appropriately for guaranteed successful prints.”

For the sake of speed and accuracy, the Dinsmore team decided to use stereolithography (SLA) to produce the 3D model. After an SLA part finishes printing, the part is left in what’s called a green state – and although the part has reached its final form, the polymerization reaction is not completed at this stage. The strongest mechanical properties will only be realized when exposed to a combination of light and heat. In order to mimic the density and surface finish of a real bone, engineers at Dinsmore chose to cure the model in a unique way, leaving it in a semi-green state that allowed the CHOC team of surgeons to receive a realistic representation of the model.

3D Printed Tibia using SLA

Once the tibia model reached Dr. Arminian’s team, they carefully mapped out their cuts and configured the external fixation construct.

Dr. Justin Roth, a surgical team member, talked about the value of having a realistic model to work from, explaining:

“For complex surgeries like this one, the 3D physical model was a great conceptual practice tool for pre-surgical planning. It gave us a tactical visualization of the deformity so we could get a better sense of what needed to be done to correct it. You can measure the deformity in CT scans, but there’s nothing like being able to hold the physical model.”

Post-Processing the 3D Printed Tibia

Taking advantage of the opportunity to put a detailed plan together prior to an operation helps reduce the risk of surgical errors and increases the chance of a fast and successful recovery for the patient. Dr. Roth also talked about the value educating the patient and their family about exact details of the operation.

“It’s nice to be able to take the model and show patients what’s going to happen during surgery,” he noted.

Needless to say, the surgery was a success. In only four months, the team of surgeons at CHOC were able to reset Campos’ normal gait and function – and after six months, Campos was able to regain the ability to walk and run without any complications.

Campos’ stepmother expressed her joy for his recovery, adding that “the surgery has had a genuine impact on his life. He is more confident in his interactions with other children and is excited to participate in activities that he used to avoid. We are so thankful for the surgical team at CHOC.”

Although 3D printing in the medical industry still has hurdles to overcome, such as receiving FDA approval for certain applications, it’s on track to become one of the leading industries to use the technology. Other medical devices produced using 3D printing include orthopedic and cranial implants, surgical instruments, dental restorations such as crowns, and external prosthetics.

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[Source/Images: Dinsmore]