Issue: Volume: 30 Issue: 1 (Jan 2007)

A Design with Heart


CAD tools and a collaborative effort bring a new medical design to life
by Jenny Donelan
 
On the whole, product designers enjoy their work—after all, it’s fun to create a sleek new cover for an electronics device or an innovative children’s toy. But their job gets even more satisfying when they’re able to design something that makes the world a better place by saving lives. Such was the case for the designers at Strategix Vision, a product design and development company based in Bozeman, Montana, when they were asked to develop a device to make heart surgery safer and less invasive.

That device, the Embrace Heart Stabilizer, holds the heart and coronary artery in position during coronary bypass surgery, allowing a surgeon to bypass the blocked artery without having to stop the heart and maintain the patient on a heart-lung machine. The procedure is therefore less risky and invasive, and makes for a shorter recovery time for the patient. What’s particularly special about the Embrace is its minimalist design, which offers the surgeon more room to work as well as better overall access to the chest cavity.

Strategix Vision developed the Embrace in conjunction with strategic product development company Herbst LaZar Bell, which provided human factors analysis and other design input, as well as with CardioVations, a division of Ethicon, a Johnson & Johnson company. The device is now marketed by CardioVations.

Laying the Groundwork

Strategix Vision employs industrial designers, mechanical and electrical engineers, and user researchers who work together to design and develop medical, industrial, scientific, and consumer products. The company had already designed numerous medical devices, such as a defibrillator and an apparatus for managing urinary incontinence, when it began collaborating with CardioVations a few years ago.

About a year before work on the Embrace even began, the two companies cooperated with each other on designs for a different heart stabilizer, using design software from SolidWorks for initial form and mechanical studies, as well as for review. This project went as far as the creation of working prototypes that were reviewed by cardio-thoracic surgeons.

When the Embrace project came along, much of the groundwork had already been laid, both in terms of tools and in inter-company communications. "It was a natural progression for us," says Kent Swendseid, design director for Strategix Vision, who notes that having an already-established relationship and a common semantic design and usability language with CardioVations made the whole Embrace project run more smoothly. "We just had to apply everything we had learned previously to a different and explicit technology. It was like writing a story in which we had set the scene and now were introducing a new character."

New Kind of Heart Stabilizer

The impetus for the Embrace, according to Strategix Vision design engineering director Marty Albini, was to improve on an existing product by making it smaller and more ergonomic. "The idea was to free up some of the space it took up in the operating theater and reduce the effort it took [for surgeons] to operate. We also wanted to make the device more intuitive to use," he says.

The team got started using Adobe’s Photoshop and Illustrator for early conceptual studies. From there, it proceeded directly to designing in SolidWorks, which it used in conjunction with Nvidia’s Quadro FX professional graphics card. This combination made it possible for the team to rotate the 3D model on screen in real time.

Says Swendseid, "It really, and I mean really, helps to be able to rotate a model in real time and not have lag and not have to wait for a redraw in order to talk about designs."

Because both CardioVations and Strategix Vision are SolidWorks users, says Albini, their team members were able to share files to review and develop the design. For other projects, he notes, Strategix Vision often uses the e-drawings module of SolidWorks, which allows non-CAD experts to review and rotate models in 3D without having to know the intricacies of the full SolidWorks package.


Designers at Strategix Visionused CAD tools and a strongcollaborative effort to designthe award-winning EmbraceHeart Stabilizer, a device thatpositions and stabilizes theheart during coronary bypasssurgery. The rendering at leftshows the interior workingsof a portion of the Stabilizer.The entire device, below,features an unobtrusiveprofi le that frees up spacein which surgeons can work.

Whatever the project and whatever the package, says Svendseid, close collaboration is part of the Strategix Vision work ethic. "Designers work closely with the engineers in our company. We try to have an open structure where everyone can have an opinion, so we had many discussions around computers and projected images in order to set directions and quickly work through new ideas," says Swendseid. "The great thing about all the visualization tools we have at hand—from sketches to CAD—is that they allow us to understand each other in a common language. I don’t know exactly how to be an engineer, but I can certainly understand what an engineer means and what that implies to a design when I can see it."  

Meeting Challenges

Even with Strategix Vision’s pre-established culture of collaboration, and even though the project was not radically different from the work the company typically performs, notes Swendseid, "the Embrace did present unique problems in ergonomics, mechanics, usability, and a specific user scenario." That last factor—the user scenario—involved a full understanding of who would be using the product, as well as how, and why. It is a vital ingredient of how designers "get it right" when creating products that people want to use.

"What we passionately strive to do," says Swendseid, "is create relevance and a great experience for the user by reaching beyond the functional requirements of a product and into its meaning."

Therefore, chief among the challenges was "forming a device that meets the mind-set of the surgeon," says Svendseid. Specifically, that meant reducing the footprint on the retractor in order to increase working space for the doctor, and creating intuitive controls for adjustments and activation, among other requirements.

"Mechanically, the biggest challenge was keeping the size down while still providing adequate force to the gooseneck to stiffen it enough to hold the heart," notes Albini.

After the design had progressed to the point of general approval, it was then tuned with rapid prototypes made in-house at Strategix Vision. "We use a variety of tools, including video projectors, to get a detailed view of what we’re working on," explains Albini. "And there are some cool visualization tools that have emerged since the Embrace was designed that are helping us now as well, like RealView, a real-time texture-map visualization feature in SolidWorks that lets you dress up the models with realistic-looking surfaces." (RealView, says Fielder Hiss, manager of product management for SolidWorks, was developed by SolidWorks in conjunction with Nvidia, and involves "almost photorealistic, real-time graphics." Designers can see the reflection of metal or the look of wood while they work, without having to wait for the file to render out.)

With or without such helpful eye candy, Albini says that at a certain juncture it’s important for designers and potential users alike to have a physical prototype to hold.




Both teams were experienced SolidWorks users, so designs andrevisions for features such as the “toes” (top) that make contact withthe heart could be reviewed in the same software. Levers and othercontrols (bottom) were designed to work as intuitively as possible.

"In medical design, you need buy-in from doctors, and the feel is paramount—how something feels their hands," says Hiss. "So it’s important to get prototypes into doctors’ hands quickly."

In fact, the designers did just that. Their work on the Embrace turned out to be breathtakingly fast: "Once the final design direction was chosen, it took about four weeks to execute, with a couple of brief corrections later on," says Albini. Of course, he’s quick to point out, all the groundwork laid beforehand has to be factored in as well.

Success

When surgeons saw one of the first Embrace units at a trade show and reacted extremely positively, the folks at Strategix Vision and CardioVations knew they had a success on their hands. This was confirmed by an IDEA award for the design from BusinessWeek magazine last year. The unit is now in production and in use.

"We can always be proud of our work as designers," says Albini, "but you can’t fool someone who uses these things every day. If they like it, it’s good. Product design is hard. There are always problems to solve, competing goals to balance, and late nights spent making it all work. A project like this makes all that worthwhile."

Jenny Donelan is a contributing editor for Computer Graphics World. She can be reached at jdonelan@adelphia.net.

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