The future is here as veterinarians explore the clinical applications of 3-D printers.
The technology of 3-D printing, also called additive manufacturing, works like this: On the basis of instructions from computer-assisted design programs, layer after layer of material is laid down in specific shapes. 3-D printing can create a solid object of virtually any shape and can use an assortment of starting materials, including plastic, metal, ceramic, and even living cells. 3-D printing is different from traditional manufacturing techniques, which rely on the removal of material by cutting or drilling, for example.
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| ||Dr. Judith A. Hudson, a radiology professor at Auburn University College of Veterinary Medicine, and Dr. Adrien-Maxence Hespel, a radiology resident, pose near a full-size dog skeleton that took almost eight days of continuous 3-D printing to bring all the parts together. This model will be used in radiology rounds as a teaching model. (Courtesy of Auburn University CVM) ||
“The technology for this has existed since the 1980s,” said Steven Lucero, mechanical engineer and manager of the Translating Engineering Advances to Medicine Prototyping Facility at the University of California-Davis. “But we’ve only seen it emerge into clinical practice in the last few years, as many of the patents on this technology are expiring and the marketplace is becoming more competitive as a result. Consequently, we’re finally getting to see the great benefits that can come from this technology.”
Finding the perfect fit
In the veterinary field, 3-D printing is being used most often at the veterinary teaching hospitals.
Cornell University College of Veterinary Medicine may have been one of the first veterinary institutions to use 3-D printing, back in 2009, thanks to a collaboration with the university’s College of Engineering.
An engineering professor and a graduate student helped Dr. Ursula Krotscheck, assistant professor of small animal surgery, prepare for a surgery on Bekka, a young German Shepherd Dog with an angular limb deformity. The computed tomographic images didn’t tell the entire story, and to be fully prepared for surgery, Dr. Krotscheck wanted a chance to study the bones.
Dr. Krotscheck was able to do just that before performing the two-hour surgery in May 2009. The engineering professor, Dr. Hod Lipson, and graduate student Daniel Cohen used a 3-D printer to fabricate medical models based on CT scans that showed the bones in Bekka’s leg. Dr. Krotscheck used these physical models to better plan the operation and customize metal plates that would be needed during surgery.
“I knew what plate to use, how to contour the plate, where it should sit on the bone, and where the cuts should be made,” Dr. Krotscheck said. “All the decision-making was done 24 hours in advance. Having access to the models prior to surgery decreased the length of time Bekka was under anesthesia, decreased the time surgery took from start to finish, and ultimately decreased the risk of infection.”
Fabricating the bones took approximately nine hours, making the technique well suited for a scheduled—as opposed to
emergency—surgery. The use of 3-D printing has been reported in the scientific literature for use with dogs only once, in
2008, according to Cornell.
“An excellent tool”
Since then, the technology has gained some popularity.
Auburn University’s Veterinary Teaching Hospital purchased a 3-D printer in July 2013 with a grant from the College of
Veterinary Medicine. The printer cost about $2,500, including an extended warranty, and the software cost around $11,000. However, the models themselves—printed with a plastic-based polymer—cost only a few dollars, and the cost is not passed on to the client if the surgeon has one printed prior to the procedure.
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A 3-D model of a patient’s skull printed at the University of California-Davis (Courtesy of University of California-Davis SVM) ||
Dr. Adrien-Maxence Hespel, a radiology resident at the college, said they print models on a case-by-case basis, generally reserving the technique for the most complicated cases. So far, multiple prototypes have been designed for small animal and equine surgeries.
In one instance, Auburn faculty performed a CT scan on a horse that had been kicked in the face and sustained a complicated fracture to the eye. They printed a model of the horse’s head to get a better idea of which implants to use and which parts of the bone had to be pushed in or pulled out.
“Thanks to a computer, we were able to create a 3-D model on a screen, but allowing this model to be printed gives us an excellent tool for communicating with our colleagues and clients,” Dr. Hespel said. “The 3-D printer allows the surgeons to evaluate more approaches to solve a problem preoperatively and may help them in deciding which solution is optimal for the patient.”
He added, “As the models can be sterilized, they can even be used during surgery as quick reference.”
Auburn faculty have also printed models of airways in dogs and cats so that when students are performing endoscopic
examinations, the model can be used as a navigation map. They’re currently working on printing a full-sized dog such as a Labrador Retriever that can be used to teach students how to identify abnormalities of the vertebral column or lungs.
Skull and bones
The University of California-Davis School of Veterinary Medicine has been using 3-D printing technology to help in the area of maxillofacial surgeries. The Dentistry & Oral Surgery Service at the Veterinary Medical Teaching Hospital has been partnering for about a year and a half with the UC-Davis Translating Engineering Advances to Medicine Prototyping Facility in the Department of Biomedical Engineering to create a cutting-edge teaching and clinical tool that has helped make maxillofacial surgeries safer and easier for clients to understand.
Currently, DOSS is the only service unit of the VMTH that uses 3-D printing to assist with surgical procedures. The staff
create 3-D printed skulls for every patient that needs any maxillofacial reconstruction as well as for certain patients that
require advanced dental surgeries. They are using this technology generally two to three times a month.
“It’s one thing to study a CT image on screen—we learn a tremendous amount about a patient that way,” said Dr. Frank
Verstraete, chief of DOSS. “But to be able to hold a replica of that same image in your hand and see exactly what your
patient’s skull looks like takes the experience to a completely different level. The advantages of that are tenfold compared
to a screen image.”