July 29, 2009

Dr. Ola Harrysson, engineering professor, works to change the lives of animals and humans with a new prosthetic limb that is fused to the bone. (ZT Pet News Photo)

NEW YORK -- Specializing in biomedical implants Dr. Ola Harrysson has revolutionized limb replacement surgeries for animals and hopefully soon, humans. It's suffice to say that the associate professor in the Edward P. Fitts Department of Industrial and Systems Engineering at NC State is on the forefront of medical technology.

Partnering with a orthopedic veterinarian from the NC State University College of Veterinary Medicine, Ola is working to perfect osseonintegration technology -- the process of fusing a prosthetic limb to the bone. Improving the quality of life for amputees, this surgical development is more efficient, comfortable and will help animals, as well as humans who could never before function with artificial limbs.

Ola talks to ZT Pet News about the four animals he has successfully performed the surgery on and how he plans to make this process accessible for animals and eventually humans around the country.

How did you first become involved with prosthetic limb research?

In the Spring 2004, the NC State University College of Veterinary Medicine and Dr. Denis Marcellin-Little, an orthopedic surgeon, were contacted by the owners of George Bailey. George Bailey was missing both back paws and one of the limbs very fully functional except for the missing paw.

Dr. Marcellin-Little and I were teaching our bio-modeling course for the first time and decided that George Bailey’s case would be a good course project for one of the student groups. Since external prosthetics do not work very well for animals we decided to try to develop an osseointegrated prosthetic instead.

How does your new process of osseointegration differ from traditional limb prosthetic procedures?

Traditional prosthetics are usually referred to as external prosthetics and use a press fit between the socket and the stump. These prosthetics are loose and can easily be taken off by the amputee. Often, a vacuum is used to hold the prosthetic in place.

The osseointegrated prosthetics are directly attached to the bone in the amputated limb and a portion of the implant is breaking the skin barrier. The external prosthetic is then attached to the protruding portion of the osseointegrated implant.

How many years have you worked developing the procedure?

The development for George Bailey started during Spring 2004 and the surgery took place early the following spring. Since then the osseointegrated implant has evolved and three more animals, one cat and two dogs, have received slightly different versions. A fifth patient, a dog, is scheduled to receive a new iteration of the implant later this summer.

George Bailey was the first cat you performed the surgery on, why him?

George Bailey was the first patient that contacted us and that is why he became the first patient to receive the osseointegrated implant.

When could this procedure become mainstream enough for owners to request this for their handicapped pets?

We are currently doing this procedure for animals in the order that they contact us and if we deem them to be good candidates. Each case takes time since we are still fine-tuning the design to improve the outcome and to make the surgery easier and more precise.

The evolution of these osseointegrated prosthetics is close collaboration between the NC State ISE engineers and the surgeons at the vet school. Dr. Denis Marcellin-Little is the main collaborator at the vet school but several other surgeons have been involved as well. It might take a couple of years before this will be considered as a mainstream procedure with a short timeline. We are still conducting research on several aspects of the implant design and the tissue response to try to optimize the outcome.

How could this benefit or extend an amputated pet's life, versus using a pet-wheel chair?

The osseointegrated prosthetic becomes a part of the pet’s leg and in all cases the animal has been able to ambulate normally using the prosthetic. It is our hope that these animal patients will be able to live a normal life after the procedure and will be able to walk and run like any other pet. The owners still have to be very involved in the process for the procedure to be a success.

Are there any known complications?

There is always a risk of infections that can occur and we are working on solutions to try to minimize this. All patients have had mild infections that have been treated with antibiotics. The skin interface seems to be the weak point but we are currently working on solving these issues.

Because of this innovative procedure, what are the implications for animals, and eventually humans?

We hope to more efficiently help both animal and human patients in the future and give them back the ability to ambulate normally. Even human patients will greatly benefit from these prosthetics since the current external prosthetics have a number of problems and issues that are difficult to solve.

When do you hope to operate on a human subject?

The research team at NCSU is currently collaborating with a research team at Duke Medical Center to be able to bring this to the human patients. Duke, in collaboration with the VA Clinic in Durham, is currently treating a number of soldiers who have returned from combat with missing limbs. It is our intention to be able to help these war veterans, as well.

Do you have any pets?

Yes, both Denis and I have two dogs each.

What pet have you always wanted to own, but never have?

I always wanted to have a monkey but I think that would be a lot of work.

When in your life did you know you were/are an animal person?

I have had different pets growing up so I have always been an animal person.

How did that realization change your life?

The biggest change in my life came when I joined the faculty at NCSU ISE and started to collaborate with Dr. Denis Marcellin-Little at the vet school. Our first project together started in Spring 2002 when a German Shepherd arrived at the vet school with severely deformed hind legs. Using medical imaging technology and medical modeling technologies we reconstructed the skeleton of the dogs back legs, which allowed Dr. Marcellin-Little to plan and rehearse the corrective surgery.

The outcome of that case was a success and since then, we have collaborated on a large number of cases where we have managed to help animal patients. We are also conducting research that is not currently helping particular patients, but in the future these research projects may change the way we treat both animals and humans with certain deformities or illnesses.

What is one thing others can do to improve the lives of animals?

Adopt pets from animal shelters and take good care of them.

For the animals in your life what would they say about your presence in their lives?

I am sure that the pets that we help are happy that we are around and that we care about their well-being.

In your opinion, what is the biggest issue animals face in our global society?

To have a pet is a great responsibility and many people don’t realize that. Animal shelters around the world are full of pets that people don’t want anymore. Many pets are left alone and have to fight for themselves to survive when the owners get tired of their responsibilities.

Many pets and animals are being mistreated or abused for no reason. I think we need to take better care of our animal friends and make sure that we don’t take on a responsibility that we can’t handle. Many of the animals that we have helped over the years have come from animal shelters.

Elisabeth Brock is an editorial intern with ZT Pet News and can be reached at ebrock@zootoo.com.