3D implants to save lives

 

At the end of 2018, just before Christmas, the owners of the 3-year-old Siberian Husky Iza found out that this stunningly beautiful dog with the large, blue eyes had a tumor of the skull wall. Although benign, the tumor grew so rapidly in size, that it pushed the brain outward through the skull.

It seemed like there was no hope for Iza...

A Christmas miracle

Then, Prof. Dr. Björn Meij, Head of Surgery at the Faculty of Veterinary Medicine came up with the ingenious idea to use the available CT scan of Iza’s skull to print a 3D implant.  The tumor was surgically removed and the titanium implant placed back on Iza’s skull to protect the brain. Iza was allowed to go home after a few short days to celebrate Christmas with her family. 

3D implants as a solution for animals

The veterinary surgeons of the Faculty of Veterinary Medicine want to show that animals with various chronic conditions can be successfully treated with 3D implants.That way, the technique of 3D printing can increasingly be integrated into veterinary medicine, as well as human medicine.

Companion animals such as dogs and cats suffer from the same diseases as their owner, the human. While the possibilities for humans have been accelerated by technical medicine, including 3D printing of tailor-made implants for the individual, the availability of this technique for the veterinary medicine of companion animals is still very limited. This is mainly due to the relatively high costs of the technology for the owners of pet animals who are generally not insured or because the condition has been excluded by the insurance.

3D printing

The process of 3D printing starts with the imaging of the condition, often a skeletal disease. The condition is mapped with computer tomography (CT), a technique based on X-rays. CT has been a diagnostic tool for companion animals for 20 years and there are more than 15 CT scanners for dogs and cats in the Netherlands. The modern CT scanner are 64-128 slice scanners that can display the condition with a resolution of 1 mm. The strong computers can then make 3D reconstructions of the skeleton and the abnormality.

Due to the universal digital format of medical imaging (dicom), the computer files can then be easily sent from one workplace to another. The dicom files are sent to the designer who then goes to work in the computer (in silico) to correct the skeletal disease or to repair the bone defect that occurs after the operation. The software used for this is only available in a limited number of locations, in research institutes at universities such as UMC Utrecht or in companies that specialize in this.

The surgical procedure can then be carefully prepared through close cooperation between the (veterinary) doctor and the designer. For example, saw cuts can be planned and even 3D printed molds can be made. The bone defect can then be repaired in the computer environment by customized 3D implants, and designer and surgeon tinker with this until a working model is created. The print order is then sent to the company that takes care of the actual 3D printing (as with 3D Systems) and the 3D implant is printed in titanium. Initially, the bones and implants are printed using plastic. This gives the surgeon the opportunity to first practice the dry operation on the artificial bones and see if the intended result can be achieved. Once that step is completed, the implants are sterilized and the operation can be planned for the patient.

Which patients are eligible for 3D printing?

The conditions that are eligible for 3D printing can be broadly divided into two groups:

1. Form abnormalities in skeletal development.

2. Too little bone. Tumors of the skeleton that are treated by surgical removal of the tumor result in a large bone defect that affects the quality of life.

In the University Clinic for Companion Animals (UKG) of the Faculty of Veterinary Medicine, experience has been gained with 3D printing with disorders that occur in both groups.

Hip dysplasia in humans and dogs

Hip dysplasia is common in dogs and humans and is an orthopedic condition that leads to lameness, a lot of pain, wear and tear and a deterioration of the quality of life. HD is characterized by an insufficiently deep hip cup and loose connection between hip head and hip cup. In a PhD study by Drs. K. Willemsen under the supervision of Prof. dr. H. Weinans (UMC Utrecht) and Prof. dr. B. Meij (UKG) was designed on the basis of CT scan of dogs with HD a 3D printed titanium implant that normalizes the connection between the bowl and head.

The aim of the current study is to treat 25 dogs with HD in the UKG, using this new technique. Following the surgical procedures, owners will be asked to complete a questionnaire that monitors the progress of the dog. Additional functional gait research on a force platform will assist in gathering sufficient evidence to eventually bring the technique to humans with hip dysplasia.

Tumors in dogs 

Tumors of the skeleton are common in the dog. For example, tumors are seen in the skull, jaws and long bones. Treatment always consists of removing the affected skeletal part with ample margins so that the tumor cannot grow back. This often leads to considerable loss of function (eg of the leg) and sometimes that loss is so great that euthanasia is the only humane way out. Often the disease can be treated by printing the missing skeleton part 3D in titanium (or a plastic) and replacing it by surgery. In the UKG incidental experience has been gained for the skull and the long bones and this has had a surprisingly good result in a few patients. Because the treatment is new and innovative, the costs are still high and extra money is needed to treat the sick animals.

Photo 1: Skull of a dog with a 3D printed titanium skull roof after the removal of a skull tumor that pushed the brain away.

The veterinary surgeons of the Faculty of Veterinary Medicine want to show that animals with various chronic conditions can be successfully treated with 3D implants.That way, the technique of 3D printing can increasingly be integrated into veterinary medicine, as well as human medicine.

Help us and support the project for 3D implants today!