Designs on Implant Innovation, Part II

An orthopedic implant is only as good as its design. Many factors can influence the design of an implant or even a component within the device, including cost, materials, regulatory requirements and patient demographics. In the last decade, innovative surgical techniques and advances in technology have played an important role in shaping new implant designs that are now becoming the standard of care among orthopedic surgeons.

To gain some insight into the thought processes behind implant design and help identify the trends shaping the sector as well as the challenges currently facing companies, Orthopedic Design & Technology spoke to several industry professionals over the last few weeks.

They included:

•  Brian R. McLaughlin, former business development manager at Orchid Design, a division of Shelton, Conn.-based Orchid Orthopedic Solutions, a contract design and manufacturing firm serving the orthopedic, dental and cardiovascular markets.

•  Josh Sprague, vice president of Hoosier Inc., a full-service spinal contract manufacturing company based in Corona, Calif.

• Jeffrey Kapec, a principal and executive vice president of Tanaka Kapec Design Group Inc., a Norwalk, Conn.-based design consultancy.

• Anand M. Vora, M.D., an orthopedic surgeon in Illinois who also teaches orthopaedic surgery at both Northwestern University Medical School and the University of Illinois Medical School. Dr. Vora also is a member of the American Academy of Orthopaedic Surgeons.

Editor’s note: This is the second of three installments of ODT’s roundtable discussion with these professionals about implant design.

ODT: What are some of the challenges to designing orthopedic implants, and how are companies/engineers overcoming these challenges?
Jeffrey Kapec: The challenges include the way the implants are visualized and designed and the way the surgical technique is performed.
Dr. Anand M. Vora: As orthopedic surgeons, we focus on the body, we focus on surgery and we focus on taking care of our patients. We are not engineers (for the most part), so the challenge is that implant companies and device companies must work hand in hand with orthopedic surgeons. We understand the specific needs of our patients and what the implants demand, but we’re not engineers. So from our perspective, the challenge is trying to integrate our knowledge base with company’s knowledge bases and trying to work together to further improve the overall armamentarium we have for our patients. Sometimes but not always, this is hampered by the conflict of interest that may be present with such a relationship. There’s a lot of concern now and rightfully so because some of these relationships between surgeons and implant makers have been under scrutiny.

There is a little bit more of a cautious relationship now between orthopedic surgeons and device makers in sharing ideas and in promoting and or endorsing implants or designs. An orthopedic surgeon creates a device and of course they’re going to promote their device but sometimes they’re not promoting the best device out there. And that’s gotten the whole industry into trouble and the whole relationship under scrutiny. I think there’s still a very appropriate and ethical way of creating these relationships. There’s a lot more concern now on both parties to make sure that we play by the rules and everything is done in an upright and ethical manner. When you do that, obviously it hampers a little bit of product development because people don’t want to be put in that position of being under that scrutiny.

A majority of time orthopedic surgeons and device companies want to work together because patient outcomes are in our best interest. I think that’s what we’re all striving to do—make the field of orthopedics better and the outcomes for our patients better.
Brian R. McLaughlin: Some of the challenges have to do with the actual design of implants and instruments, with the various materials, with sourcing, and even getting valid clinical feedback from a wide enough group of surgeons to demonstrate market acceptance. Certainly the regulatory environment is a challenge for products getting to market now, almost to the point where it is stifling innovation. The more innovative your implant solution, the higher likelihood you are to have to do clinical trials, which makes the road to commercialization that much longer, and that much more expensive.
Josh Sprague: With implants, there is cost, uniqueness and patent protection or patents work around. As a typical consumer we always want the Ferrari for the price of a Pinto right? Many of our customers want the same thing when it comes to their implants, which of course is a challenge. One cost driver is the patent work feature. At this point many patents have expired in the spinal space, but we still see some features on occasion that are ridiculous to make, but are simply in place to get around an existing patent.

The more significant challenge is not the design of the implant, it’s the design of the instruments. Functionality, durability, and cost are all major challenges with instruments. Most instrument trays for spine surgery are given to the hospital on consignment or loan, often for free. If you’ve ever looked at an instrument tray you’ll quickly realize that those cases are far from inexpensive. Designing a cost effective, low volume instrument is very challenging. Making it durable and something of novelty is very challenging as well, regardless of cost.

ODT: Where do surgeons and/or engineers get their ideas for new orthopedic implants?
Vora: We get our implant designs by listening to engineers but we also get our implant design ideas by performing procedures and looking at procedures that we’re doing and seeing where we find limitations. By looking at the limitations we learn from our mistakes and find ways of correcting our mistakes to create something better. As we become more sub-specialized, some of the things we learn are things that we borrow from other orthopedic specialties. For example, I am a foot and ankle surgeon. Some of the things that we’re doing right now to help treat certain conditions like bunions we’re able to do much better because we are able to take some of the technology that people are using elsewhere in the body for other types of procedures and apply them to bunion correction. We’re able to learn from our colleagues within other specialties and also within our specialty.
Sprague: Reduced surgery time, cost or for a procedure that currently does not have the optimum implant. We’ve seen a variety of new implants pop up that are unique twists that the standard cage for very limited applications. Sometimes it’s for patients that have unique degenerative problems that are far from the norm of society, others it’s for a surgeon that is trying to find ways of minimizing the invasive time of the surgery.
Kapec: In the O.R. while they’re watching surgeons work. We try to do that as much as we can; it’s very important. At the lunch table after surgery with napkins, pencils and markers. In meetings afterward at dinner where there’s time to be creative without having to worry about scheduling the next surgery. At seminars. At scheduled meetings between manufacturers and surgeons. And in cadaver labs or some other model to represent conditions of surgery. All of these are places where ideas emerge.

The engineer may come up with a bunch of ideas that he wants to try out so he makes prototypes and presents it to the surgeon and the surgeon may try them in a benchtop model and he may think about it. He may go back and say, ‘Let’s try this out. Let’s make these changes for me.’ It’s this trial and error, iterative process that is really important. It does take a while, but if you have good technique, you can accelerate that process. It may take about six months for us to go through a whole host of ideas that surgeons have tried out and really knock it down to something that really works for a broad-based spectrum of surgeons.

It’s a dialogue. It’s like having a good conversation with someone, and being open minded and listening very carefully. It’s back and forth. You hear something. You listen carefully. You respond to it You give them something. They try it out and they say ‘Yes, this is right, but this is not quite right.’ The important thing is it’s an iterative process, it’s back and forth. You keep adjusting and trialing until you begin to see that you’ve established a really good outcome that is intuitive for the surgeon—it makes sense for them to use, to apply, to adjust. We do see that in the design of implants and the instrumentation—there’s much more being done to try to get the simplicity of the design. The knees are very, very complicated and so much is being done with templates now so that you can be sure about what you’re doing. You can adjust and check your final placement before you do the cutting. Templates have become very important. Templates have allowed them to see ahead of time whether they have something that’s right. As a side note, visualization tools have been improving over time. Now there are visualization tools that can go in the O.R., take a quick shot so you can see relationships of implant to anatomy internally and you can do it rapidly through the entire course of surgery. That has become another component of this whole process. It’s not necessarily a part of implant design but it allows the surgeon to see how everything is going together. I’ve seen this a lot in spinal surgery. During the course of surgery, the surgeon may take 10 shots as he’s going along to make sure that everything is going well. They couldn’t do that in the past – they had such big, cumbersome equipment. But now, the equipment is getting smaller. They can wheel it around. They can adjust it. They can adjust the table. They can do things that are more conducive to giving a surgeon more information about what’s going on so he’s not working blinded. And that is a very important side growth of the surgical technique—the instruments and the equipment is giving the surgeon better visualization of what is going on step by step.
McLaughlin: Experience. For surgeons, seeing problems on a daily basis is where they come up with ideas on how to make the patient’s lives better. Their ideas are driven by problems they are seeing with implant systems they are using, and how to improve them. Engineers however aren’t necessarily the ones who come up with all the good ideas, but instead are tasked with making those ideas work, and in the process of doing so, generate more ideas, leading to new avenues for various and different solutions.