With the exponential advances in technology during the past several decades, the use of computers has permeated everyday life in myriad ways and continues to grow. The number of personal computers in use worldwide is expected to reach one billion by 2007, and roughly 70% of U.S. households boast a computer. As the use of computers has proliferated, so too have their applications. Computer-aided design/computer-aided manufacturing (CAD/CAM) is one application that has expanded as computer use has become widespread.
Initially used in the mid-1960s by large companies in the aerospace and automotive industries, CAD/CAM has become increasingly used by all types of industries as computers have become more affordable. For the O&P industry, the use of CAD/CAM, which has emerged slowly during the past 20 years, appears to be growing.
In the O&P industry, a CAD/CAM system generally includes three components: a measuring system or digitizer, a computer with design software and a carving or milling machine. Two of these three components, the digitizer and a computer with design software, or what is called a front-end system, are necessary components for creating O&P devices using computer-aided design.
The third component, the milling or carving machine, which represents a large investment and can cost anywhere from $47,000 to $250,000, often is not affordable or practical for an O&P practice. Instead, using a central fabrication facility that has the ability to manufacture a device created with CAD frequently is the route taken by O&P practices.
“It really shines when you have a centralized fabrication of some type, whether it is on a national level, a regional level or a market level,” said John P. Spaeth, MS, CP, regional vice president and director of the Insignia CAD/CAM program for Hanger Orthopedic Group Inc. “A mom-and-pop, a one op, might have difficulty justifying the expense. Unless it is a single owner or a single shop that has a high volume, I do not know that they would ever recoup that investment.”
In contrast, a front-end system without a carver can be purchased for as little as $1,400. Many companies that manufacture CAD/CAM systems offer a variety of configurations for O&P practices that want to purchase a system.
“There are lots of options depending on the type of financial investment that practitioners want to make. We have a product that is called CANFIT Access, which is a low initial cost product but you pay on a per-use basis,” said Carl Saunders, chief executive officer of Vorum Research Corp. “Each time you send a carving off to a central fab, you pay a per-use fee for that.”
Digitizers and shape capture
Digitizers, or measurement and shape acquisition tools, also come in a variety of options. There are several basic methods of obtaining patients’ measurements. The first is to take a patient’s measurements in a traditional fashion and then input those measurements into the computer. The second method is to use an electromagnetic contact imager that makes surface contact with a patient’s skin to capture image surface data of the patient. The third basic shape capture method is to use a noncontact optical scanner to obtain measurements from a patient.
“Each method has its own application and benefits, and they are not mutually exclusive,” said Jennifer Dowell, CPO, LPO, an orthotist and prosthetist for Ohio Willow Wood who is actively involved in the clinical development and testing of the OMEGA Tracer. They provide different abilities, and each has their own thing that they do really well.
Saunders said, “I think one of the things that is not obvious is some scanners are much better for certain applications than others. One of the things that is key is for people to make sure they are aware of what the scanning capabilities really are and if they can address all of the clinical needs that they want to with a CAD system.”
A more recently developed method for shape capture is the use of portable handheld scanners. This lightweight type of scanner can be contact or noncontact. Handheld scanners offer practitioners versatility and may be especially well-suited for orthotics, which Dowell noted is a much more difficult medium for shape capture than prosthetics.
Contact digitizing, in which a sensor pin actually contacts and slightly deflects the tissue of the undersurface of the foot, is a unique method of shape capture that Amfit Inc. developed for measuring feet for custom insoles. The sensor pins can be urged upward by a variable amount of force, providing insight into the underlying bone tissue.
“What happens is you end up with a more effective correction in the finished device because it deflects soft tissue to a greater degree than it does hard tissue,” said Arjen Sundman, president of Amfit Inc. “Anything that simply samples the surface of the foot does not have insight into the underlying bone structure and that is the critical difference between our digitizer and any other method of measuring the undersurface of a person’s foot.”
Sundman noted all of their technology is focused in the measurement technique using their contact digitizer, the FootFax, and that “it really is paramount to what we do that we address the biomechanics of the plantar surface of the foot. That is what drove the design of the machine.”
An additional method of shape acquisition is the use of computed tomography (CT) and magnetic resonance imaging (MRI) scans.
“In the past, we have worked with CT and MRI scans to create three-dimensional models that way. We also have the ability to use a library of models and then take measurements and create three-dimensional shapes from a library,” said Mark Mazloff, MBME, a mechanical engineer for BioSculptor Corp. “Basically, what we also have done is we have left our system pretty open in the sense that we can use any commercially available scanner … we can work with any scanner or method of getting the shape into the computer that is available on the market.”
One method of shape capture currently not available in the United States is a prosthetic scanner that has been developed by Ossur. The scanner is a static machine that scans any object placed inside. This method is used predominantly for transtibial amputees, who sit in an elevated chair and hold their residual limb inside a device that looks like a small MRI scanner placed on its side. The device then goes around the circumference and actually measures the patient’s residual limb.
“If everything is stable in that system in terms of the patient not moving, then that is the most accurate way of collecting data, even more so than the hand scanner, which has some minor error relative to vibration and what not,” said Ian Fothergill, clinical marketing manager for Ossur North America.
The design software, the most crucial aspect to the success of CAD/CAM, is an area that has proven especially problematic in the O&P field for many reasons. One of the most fundamental challenges of developing CAD/CAM in the O&P industry is that every device is one of a kind and individualized to a specific patient.
“It is ironic because every single shape a clinician makes is unique. In a major industry like automotive, they are using CAD/CAM technology to make thousands and thousands of widgets all the same, and in our effort, we are trying to make tens and hundreds of orthopedic devices where each one is different,” said Saunders. “You can imagine that that puts a lot of pressure on the developers to make sure they provide the tools that can do all these different things.”
Because each device is unique, CAD software for the O&P industry must be flexible to give practitioners the ability to create and modify the designs of the different types of componentry they make.
“We cannot model our modification or our shape capture or any of this after one specific philosophy. It has to be flexible enough that anyone who chooses to use this tool can make it work the way they expect it to,” said Dowell. “It cannot be a rigid system that you have to use our templates, you have to use our measurements, you have to use it this way for it to work. From our standpoint, CAD does not work that way. It has to be a tool that lets you do the things you do by hand now and gives you a more efficient way to do it electronically.”
Another challenge unique to the O&P industry is that practitioners traditionally have created each device manually, almost in an artisan fashion. For many practitioners, using a computer to design O&P devices can require a new mindset and a fundamental change in how they practice.
“Fundamentally, the biggest challenge is still that people in this industry have a lot of faith in their hands, being able to make stuff with their hands,” said Saunders. “The majority of their training in school is how to make stuff manually, so trying to get them to be confident that they can produce a comparable product using the computers is a big deal, but part of that too has to be the responsibility of the developers to make that experience as lifelike and as close to the real thing as possible, and technology now gives you that capability.”
Despite being available to O&P practitioners for approximately 20 years, CAD/CAM in many ways is still an emerging technology that continues to evolve.
“Keep in mind this is emerging technology. CAD has been emerging for many years, and it has never seemed to have a strong toehold anywhere, so when we looked at the use of CAD for our company, what we did not want was a start-and-stop effort,” said Spaeth. “We wanted to be sure that what we did was meaningful to our business and to our practitioners, and our patients, and by meaningful, I mean it had to provide a less invasive environment for the data acquisition. It had to create efficiencies in the way we practice, and it had to produce some discrete products that were as good as or better than what could be produced with plaster.”
Early CAD/CAM systems were a far cry from today’s systems, affording practitioners with limited applications. Consequently, results often fell short of expectations.
“I think that CAD/CAM started early here in the United States, and a lot of facilities bought some early models and had poor results with them, so it kind of damaged the motivation to keep pursuing that angle,” said Fothergill.
In addition, creating CAD/CAM systems for O&P applications 20 years ago was a “struggle,” said Saunders, who also noted that at the time, many practitioners were afraid of using computers.
“We did the best we could then, but it is certainly nothing like what we can do now,” said Saunders. “In the conventional computer industry, major software upgrades occur within 3 to 4 years. Why has it taken so long in the O&P industry? When you really put that question forward, you will find that the biggest reasons are that the stuff we do is pretty complicated and it takes a huge investment to turn out a viable product for this industry.”
Initially, development of CAD focused on prosthetic applications, with orthotic applications being almost nonexistent. Within the past several years, however, that has changed. Advances in technology have enabled orthotics to be included in CAD/CAM systems. At the same time, the demand for systems that can address both orthotic and prosthetic needs has grown.
“Everyone wants everything in the system. We have to be able to open up the envelope of how many different types of clinical situations we can handle with CAD,” said Dowell. “Ten years ago, CAD was below-knee prosthetics – that was it. That was what it did, and anything outside of that, you still had to roll out the plaster. The envelope has opened so big as to what it is you can do using CAD and the instances we have to pull out the plaster bandage are getting fewer and fewer.”
Wide range of devices
Currently, several CAD/CAM systems are available that allow practitioners to design a wide range of both orthotic and prosthetic devices. Systems include various computer tools that allow practitioners to make modifications as needed.
“What we can do in the OMEGA Tracer software is phenomenal,” said Dowell. “There is little I cannot do in the software with my modification tools.”
Finally, as with any type of computer software on the market, technological advances result in updates to the software, often on an almost continuous basis. Consequently, CAD software in the O&P industry is a work in progress, changing frequently.
“It is constantly growing. It is constantly expanding as technology moves forward, and because of our compatibility with any type of input device as well as our compatibility with any type of output device … we have the ability to do pretty much anything,” said
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Mary L. Jerrell, ELS is a correspondent for O&P Business News.