CAD/CAM’s Expanding Potential

By Miki Fairley
Rodin 4D

Rodin4D CAD/CAM software. Image courtesy of Rodin4D.

Imagine taking a scoliosis patient's measurements by snapping a photograph and importing the image into CAD software. Imagine using this data not only to digitally design and modify the brace but also to test it for the desired in-brace modifications before actually fabricating and fitting it on a patient. These capabilities-and others like it-are no longer imaginary; they are increasingly becoming part of O&P clinical practice, thanks to quantum leaps in computer, scanning, and CAD/CAM technologies.

Current numbers weren't available as of this writing, but several industry observers told The O&P EDGE that they believe the use of CAD/CAM has increased significantly since the 2007 Practice Analysis of Certified Practitioners in the Disciplines of Orthotics and Prosthetics, published by the American Board for Certification in Orthotics, Prosthetics & Pedorthics (ABC). According to the 2007 Practice Analysis, credentialed orthotists and prosthetists used CAD/CAM for 16 percent of the orthotic devices and 24 percent of the prosthetic devices they provided. Joan Sanders, PhD, professor in the Bioengineering Department at the University of Washington, Seattle, says interest appears to be growing as the technology becomes more productive, affordable, and user-friendly. "Whenever I present on CAD/CAM at the Academy's [American Academy of Orthotists and Prosthetists] Annual Meeting, the room is full," she says. "I get the feeling that prosthetists realize it's inevitable."

Other evidence seems to bear this out: Texas Scottish Rite Hospital for Children (TSRHC), Dallas, has transitioned to CAD/CAM for the scanning, design, and fabrication of almost all of its scoliosis braces, about 400 a year, as well as other types of devices, according to Don Virostek, CPO, LPO, director of orthotics. The Speedway Children's Charities awarded TSRHC a $150,000 grant to purchase a CAD/CAM system; the hospital decided on Vorum's Canfit™ Design Software. "We looked for what we felt would be best for both orthotics and prosthetics, and for some of the particulars that we specialize in here at our hospital," Virostek says. "We've been very happy with it." He notes how much faster scanning is than traditional plaster casting, making it an ideal solution for children-not to mention that it eliminates the messy casting process. "Plus, the kids like to watch their shape being scanned on the computer screen."

There are a number of other benefits to using CAD/CAM as a part of the O&P device fabrication process:

  • Easily portable scanners mean patients can be scanned in almost any location.
  • A faster process without plaster casting makes the experience much more comfortable for the patient.
  • Storage space used for plaster casts is freed up for an additional patient room or other uses.
  • Designs are easily repeatable.
  • Electronic files form an easily available "library" and serve as documentation of a patient's shape and volume changes over time.

In addition to being able to view a model before and after modification, CAD/CAM can also help to foster collaboration on complex device design. "With a computer model, I can take a file in Europe and collaborate with someone in South Africa," says Jennifer Dowell, CPO, OMEGA® development clinician, WillowWood, Mt. Sterling, Ohio. "Both of us can look at the model and make modifications in real time-no borders. We can transfer files, make modifications, and learn new techniques."

Types of 3D Scanners

There are two main types of optical 3D scanners currently used in O&P: laser and structured (white) light. Both provide accurate 3D models of scanned surfaces, explains Shapegrabber, a 3D scanner technology company in Ottawa, Ontario, Canada. Both types render the actual surface area of an object into an electronic form called a "point cloud." When the light hits the object and is reflected back to a camera, a measurement is taken that calculates depth. When tens or hundreds of thousands of these measurements are taken per inch of object, the scan data provides a picture of the object's shape.

Lasers can emit very small, focused beams, making them precise and reliable. They are usable in almost all indoor light conditions and provide excellent depth resolution for measuring detailed features. Structured light scanners use a "white light" source such as halogen or LED to project a blanket-like pattern of pixels that deforms when it strikes the target surface; the 3D shape is created from measurements based on the light pattern deformations.

The chief advantage of structured-light 3D scanners is speed. Instead of scanning one point at a time, they scan multiple points or the entire field of view at once, eliminating motion distortion. (Author's note: For more information, visit blog.shapegrabber.com/2012/06/
optical-3d-scanninglaser- beam-or-structured-light.html
)

A new structured-light technology, apparently not yet used in O&P, is LED blue light. Blue-light scanners use a longerlasting light source than white light and can filter out other light when capturing an object (white-light scanners are sensitive to ambient light), according to a blog by Rob Glassburn, PE, vice president of operations at 3D Engineering Solutions, Cincinnati, Ohio. (Author's note: For more information, visit 3d-scan.blogspot.com/2012/
01/new-structured-lightscanning- tool.html
)

Creative CAD/CAM Solutions

CAD/CAM applications are advancing almost as quickly as the technology itself, including a number of O&P specific applications:

Software Tests Curve Correction

Rodin 4D

Screenshot of the Rodin4D software being used to design and modify an O&P device. Image courtesy of Rodin4D.

New software has made it possible to know that a scoliosis orthosis will provide the needed curve correction before it's fabricated and fitted to the patient, saving time and money. Development of the new software began in 2009 and is a collaboration between Sainte-Justine University Hospital, Montréal, Québec, Canada; the École Polytechnique de Montréal; Boston Brace, Avon, Massachusetts; and Rodin4D, Pessac, France. The software, which is based largely on work by École Polytechnique doctoral candidate Julien Clin, is "essentially...a virtual fitting of the brace," says James "Jim" Wynne, CPO, FAAOP, vice president and director of education at Boston Brace. "Using a finite element model designed with the Rodin4D software, we get a prediction of what the in-brace correction would be and can modify and optimize the brace before it's actually fabricated."

Rodin 4D

The Rodin4D M4D scanner uses structured (white)-light technology to rapidly capture a shape. Images courtesy of Rodin4D.

Rodin 4D

For about the last two years, patients at Sainte-Justine have been fitted with the simulated brace along with a traditionally designed and fabricated brace. "We then do inbrace x-rays of both, and if they are comparable, the patients then decide which brace they want. The hospital uses a lowradiation technology, the EOS® [EOS Imaging, Paris, France], which allows multiple x-rays." Testing is under way at Boston' Braces clinical division, National Orthotics and Prosthetics Company (NOPCO) facilities, and release to the general orthotic community is expected by midsummer or early fall, according to Wynne. Boston Brace currently produces about 200 scoliosis braces from CAD, along with all of its cranial remolding helmets and a large percentage of custom knee orthoses, he adds.

Software Allows Measurement by Smartphone, Tablet

Rodin4D, a division of Lagarrigue, headquartered in Toulouse, France, developer of the Rodin4D (R4D) CAD/CAM system, recently introduced the CAPTEVIA© software application, which enables measuring a patient for a spinal orthosis simply by taking a photo with an iPhone® 4, iPad® 2, or iPod touch®. According to Rodin4D, the interface takes advantage of the sensors (accelerometer, inclinometer) in these Apple devices to provide optimal patient photos. The photos can then be imported to R4D CAD/CAM software equipped with the "Import CAPTEVIA" option. The free application is available for download from iTunes.

The next version will allow measurement for knee orthoses and cervical collars, according to the company. Using structured-light technology, the Rodin4D M4D scanner features fast acquisition and an intuitive, easy-to-learn user interface. Scans can be imported into R4D CAD/CAM in about one minute, according to the company; no manual post-treatment is required; the stereolithography (STL) file is created automatically, ready for modification or carving. First introduced in March 2012, the MD4 scanner is now available in a lighter, faster, and more portable model fully integrated into R4D CAD/CAM, according to the company. The M4D was developed by Rodin4D in cooperation with Techmed3D, Lévis, Québec, and Creaform, Lévis.

RD4 CAD/CAM software, Version 5, is compatible with NVIDIA 3D Vision® glasses. "This viewing technique [viewing forms in 3D relief] allows the volume and size of virtual devices to be visualized more accurately and makes orthopedic rectifications much easier, more agreeable, and more efficient," according to a company news release. Currently the Rodin4D system is distributed in Europe, Africa, and North America. (Author's note: Boston Brace is the U.S. distributor for Rodin4D.)

Rodin-4D image Rodin-4D images

Images courtesy of Rodin-4D.

Portable Technology Increases Accessibility

Vorum, Vancouver, British Columbia, Canada, has developed a portable, handheld 3D structured-light scanner called Spectra™. According to Vorum, Spectra was developed exclusively for the O&P field. "We feel strongly that the release of our Spectra scanner along with Vorum's flexible Canfit Design Software offerings will make CAD technology accessible to any P&O clinic that wants to move forward with technology, regardless of clinic size," says Carl Saunders, CEO. "CAD technology should be inclusive, not exclusive."

scanner robotic carving system

Vorum's Spectra scanner (above, left) uses an LED projector and a single camera to capture the 3D image. Vorum's new seven-axis robotic carving system (above, right, and below) utilizes a touch screen and software customized for carving prosthetic and orthotic shapes.

robotic carving system Vorum booth at the AAOP 2013 meeting

Vorum demonstrates its new Spectra Scanner and the Canfit Design Software at the 2013 Academy Annual Meeting & Scientific Symposium. Photographs courtesy of Vorum.

At the time of this writing, Vorum was finalizing version 14.0 of the Canfit Design Software that includes a single-user interface to design custom foot orthotics, all other lower-limb orthotics, spinal orthotics, custom seats, and prosthetic sockets; release is expected this summer, according to the company.

System Allows Faster Image Capture

WillowWood, Mt. Sterling, Ohio, has added two new pieces to its OMEGA Tracer® CAD/CAM system. A new version of the software, OMEGA 2013, is expected to be released in late summer. "We did a complete redesign of the interface to make it more user-friendly for people new to CAD/ CAM as well as experienced users," Dowell says. Highlights include easier navigation and more intuitive tools, she says. "We changed our file management, included new measurement and modification tools, and made the system more customizable, which will aid ease of learning and increases its efficiency.

"A cornerstone of the OMEGA system is that it is specifically designed for clinicians," she continues. "Modification tools and terminology reflect the clinician's perspective." The new OMEGA scanner uses structured-light technology rather than a laser. "It scans much faster, so it's more comfortable for our patients and increases our efficiency," Dowell says. "This new technology reduces the dependency on dots and stickers to capture the shape. However, if there are some anatomical landmarks the clinician wants to identify, a locator target can be placed and automatically brought into the software." The scanner was released at the beginning of April.

Barriers to Use Waning

Historically, the relatively high cost of CAD/CAM systems and the learning curve involved to use them have been barriers to more widespread use of CAD/ CAM; however, scanner and software costs have decreased while technologies have improved and become more user-friendly. Regardless, the biggest cost is still the carver, so in most cases, smaller O&P facilities send the file of the modified orthotic/prosthetic design to a central fabrication facility to carve the positive mold and manufacture the device. And, as the saying goes, "there's the rub." Although design errors and other glitches can impede the process, research by Sanders and colleagues has shown that inconsistency in quality of devices produced by central fabrication facilities using CAD/CAM remains an issue.

In a series of research studies dating from 2007 to 2012, Sanders and colleagues looked at various aspects of the CAD/CAM socket fabrication process:

  • Comparing the accuracy of transtibial prosthetic sockets made by central fabrication facilities with their corresponding Academy electronic shape files and assessing the central fabrication process (CAD/CAM Transtibial Prosthetic Sockets from Central Fabrication Facilities: How Accurate Are They? Journal of Rehabilitation Research & Development (JRRD), 2007 vol. 44, no. 3, pg. 395-406).
  • Investigating the shape differences between carved models and electronic file shapes to determine if carving was a major source of socket manufacturing error in central fabrication (Central Fabrication: Carved Positive Assessment, Prosthetics and Orthotics International, March 2011 vol. 35 no. 1, pg. 81-9).
  • Comparing socket manufacturing errors with clinical assessment of socket fit, with the objective of pursuing quality standards in CAM. Of the 33 sockets tested, 23 were clinically deemed to need modification (Computer-Socket Manufacturing Error: How Much before it is Clinically Apparent? JRRD, 2012 vol. 49, no. 4, pg. 567-82).
  • Presenting an assessment technique to help central fabrication facilities and CAD/CAM equipment manufacturers to improve the quality and consistency of CAM-produced devices (Assessment Technique for Computer-Aided Manufactured Sockets, JRRD, 2011 vol. 48, no. 7, pg. 763-74).

A low-cost sensor scanner device to very accurately measure the inside socket shape would provide an extremely valuable tool to assess quality, she continues. "I hope someone develops this." She also sees a promising future for additive (direct) manufacturing. "You don't even make a positive model; it has the potential to be much more accurate." Although the research summarized above focuses on transtibial sockets, results may also apply to other devices.

Following the Technology Curve: CAD/CAM's Future Role

In a 1989 editorial in the Journal of Prosthetics and Orthotics, titled "Reflections on CAD/CAM in Prosthetics and Orthotics," John Michael, MEd, CPO, alludes to "our unspoken fears of being displaced by computerized technology." Using the example of authors and word processors, he points out that although computerized word processors had almost entirely eliminated handwritten manuscripts, "it is the skill and ability of the author that determines the ultimate quality of the manuscript. Optimal design for prosthetic and orthotic devices requires similar skill and knowledge." Computerization may become to the practitioner what a word processor has become to the author: "an incredibly powerful tool to enhance the creative process and to record successive iterations for future enhancements."

Miki Fairley is a freelance writer based in southwest Colorado. She can be contacted via e-mail at

Editor's note: The O&P EDGE does not endorse any products or vendors. Space does not allow us to include a comprehensive listing of all O&P-related CAD/CAM products on the market. This article provides a representative sample only and is for informational purposes.