Imagine that you’re an orthopedic surgeon, working on a patient with a deformity of the left tibia – known to lay people as the shinbone.
In the year 1950, your only option would be to break or cut the bone, immediately set it into a relatively straight orientation, and then place it into an immobilizing plaster cast. The rapid correction could be extremely damaging to the surrounding soft tissue, and the repaired limb might prove to be shorter than its non-deformed counterpart. Only a year later in 1951, a new device – the external fixator – appeared. Developed by a Soviet doctor named Gavriil Ilizarov, it would use a combination of rings and struts to apply pressure to the bone and slowly bring it closer to normal – even growing new bone tissue to increase the resulting limb length.
Now let’s fast-forward to 2001. The Ilizarov device has seen significant change, thanks to an American doctor, J. Charles Taylor, who introduced the Taylor Spatial FrameTM. The basics are the same, with two metal rings encircling the patient’s leg, and six adjustable struts connecting the rings. The rings are surgically attached to the bone with very fine wires, so, by adjusting the struts incrementally, the surgeon can manipulate the bone back into place. With six degrees of freedom, the device can achieve virtually any relative positioning of the bone fragments, moving them closer together or farther apart, translating or angling them in three dimensions, and even rotating the moving fragment around its long axis. And the device now uses software to guide the doctor’s adjustments.
There’s a problem. Don’t forget – this is still 2001. The Taylor software comes to you on a CD-ROM. You take your initial measurements of the bone, enter them into the system, and you get back a table that shows the adjustments you’ll need to make. But what if one of your measurements is off? With no physical representation of the frame and the deformity under correction, the software is unable to identify impossible-to-assemble frame configurations or detect interference problems that might occur during the deformity correction. And with no visual feedback, a mistake might go unnoticed well into the correction, lengthening the patient’s discomfort.
Now let’s move ahead to the present. You’re not using a CD anymore, you’re using a Web browser. And you’re suddenly looking at an image of the patient’s bone. In fact, you’re able to look at any number of images – before the correction, after the correction, and each step in between. You can now see exactly where the adjustments will move the bone, and how many adjustments it will take until you’re done. The entire pre-operative planning process, which was previously very time-consuming, can now take less than an hour.
Smith & Nephew, NetIDEAS and Pro/ENGINEER. So your life as an orthopedic surgeon has gotten a lot better thanks to your medical device supplier, Memphis-based Smith & Nephew; their application service provider, New Jersey-based NetIDEAS Inc.; and Pro/ENGINEER.
Here’s the connection. In 2001, Smith & Nephew was looking for a way to boost sales of their Taylor Spatial Frame devices. Doctors didn’t like the difficulty – and the time – required to work with the CD based product.
“What often happened was that the doctor would call us for help with the measurements, and we’d end up putting an engineer and a programmer on the phone with the doctor, sometimes for hours,” says Anthony James vice president of product development for Smith & Nephew. “So it was taking too much time for everybody.”
Smith & Nephew worked with their product development application service provider, NetIDEAS, to improve the product.
Anthony describes the result: “We brought the product to market in 2002, and our hope was to gain 100 customers a year for the first four years,” he says. “As it turned out, in our first year we gained more than 1,000 customers.”
Making the J-Link connection. Supporting the new product is Pro/ENGINEER Wildfire. Connecting Pro/ENGINEER to the surgeon are J-Link and WebLink, JAVA and JAVA Script APIs in Pro/ENGINEER. These Java development tools let NetIDEAS build a Java application to connect the user’s Web browser to a remote session of Pro/ENGINEER.
“The surgeon enters case information in standard Web forms,” says Jon Langlois, lead software engineer for NetIDEAS, “and the Web server uses that information to drive a back-end Pro/ENGINEER session. J-Link calls are used to suppress or enable individual frame parts, take measurements, and capture images to be displayed in the resulting Web page.” NetIDEAS employs server clusters with load balancing to maximize reliability. Also, all file transfers are fully encrypted for privacy purposes.
“The Pro/ENGINEER model includes a parameter-driven 'dowel' representation of a broken bone, so we can provide visual feedback that the surgeon can compare directly to his or her x-rays. If a measurement error has occurred, or a direction accidentally reversed, the doctor knows right away – not after the frame has been mounted on the patient and the correction already begun,” Langlois says.
Constraint checking and Mechanism Design. Pro/ENGINEER is helpful in a number of ways, according to Langlois. For one, it automatically checks constraints, so it can flag frame configurations that can’t be built in the real world, like when certain combinations of strut lengths simply aren’t possible. When Pro/ENGINEER regenerates the model, it detects the problem immediately, avoiding a frustrating – and painful – experience for doctor and patient.
The actual device uses a variety of strut sizes to accommodate different bone sizes. So a prescription might call for a certain strut for the first two weeks of treatment, and then a different strut for the final two weeks. It’s up to the doctor to change out the struts at the appropriate time.
“Through constraint-checking, Pro/ENGINEER automatically flags that change, and builds it into the prescription. Also, the doctor’s browser highlights the change, so the doctor will know to order the new strut in time to make the change,” says Langlois.
NetIDEAS also uses Pro/ENGINEER Mechanism Design Extension to simulate various renditions of the model. This helps the software adjust to each doctor’s style, rather than forcing the doctor to adjust to the system.
“The doctor can give us his or her optimal placement of the two rings, and Pro/ENGINEER will respond with the correct strut lengths,” says Langlois. “Or the doctor can give us the strut lengths, and Pro/ENGINEER will show where the rings should be placed.”
Yes it’s true. Pro/ENGINEER is helping orthopedic surgeons in a very unique way. And it has helped NetIDEAS win the loyalty of its customer, Smith & Nephew. Says Anthony James, “NetIDEAS’ ability to build and host this application using Pro/ENGINEER was key to our decision to build this partnership, and to giving the Taylor Spatial Frame a tremendous jumpstart in the marketplace.”
NetIDEAS, Inc., based in Mount Laurel, New Jersey, is a leading Product Lifecycle Management expert providing enterprise software hosting and technical consulting services.
Smith & Nephew has offices around the world. They develop and market advanced medical devices that help healthcare professionals treat patients more effectively.
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