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Pushing to Improve

Posted by on Wednesday, April 28, 2010 in Next, Spring 2010.

Smaller. Less invasive. More flexible. Those aren’t just directives from physicians regarding medical devices—they’re the goals that Assistant Professor of Mechanical Engineering Robert Webster III has set for his research and lab.

“The thing that drives me to continue to work really hard is the end product medically,” he says. “Will it do something that doctors can’t do today? Will it be less invasive? Will it make things better for the patient? If it’s just academic and I can’t see how it’s going to help, I’m not as interested.”

Webster’s patented development of several types of steerable medical needles already provides safer, less invasive and more accurate ways for physicians to deliver treatments to patients. Despite initial successes, however, he is continually pushing to improve, working toward swallowable robots, image-guided cochlear implants, and less invasive and more dexterous laparoscopic instruments.

A Commitment To Collaboration

The connection between mechanical engineering and medicine is at the core of Webster’s work. In fact, it was the collaborative atmosphere between medical center and university that made Vanderbilt stand out when Webster sought his first faculty position after earning his doctorate from Johns Hopkins University in 2007. Today the assistant professor is involved in a variety of projects with Vanderbilt University Medical Center. He frequently makes the short walk from the School of Engineering to the Medical Center. “Just being close to one another physically— you can’t underestimate how important that is,” Webster says of his collaborations with VUMC doctors and researchers.

Webster’s commitment to collaboration set him apart early on, says Allison Okamura, Webster’s graduate advisor at Johns Hopkins and professor of mechanical engineering there.

“He’s always willing to talk to people about his research and his ideas and seek out help from all kinds of people, whether it’s an engineer with a different specialty or a medical professional,” Okamura says.

Webster believes engineers and doctors enhance each other, although their thought processes are different. “Doctors can sometimes be too close to the problem to think outside the box. Ideas generated solely by doctors without engineering input can often, with some exceptions, of course, be small tweaks on existing tools,” he says. “Engineers tend to have the opposite problem. Many of the ‘breakthroughs’ that we would come up with on our own don’t work at all clinically. It takes just the right partnership to have a doctor who is willing to think outside the box and an engineer willing to take the time to understand the real-world challenges doctors face every day.”

Webster has that kind of partnership with a number of Vanderbilt’s leading researchers, including Dr. Robert Labadie, associate professor in the Medical Center’s Department of Otolaryngology, and J. Michael Fitzpatrick, professor of computer science, computer engineering and electrical engineering. They are working on a procedure to make cochlear implants—devices implanted inside the ear to help those with profound hearing loss—less invasive.

Previously, implantation required the removal of a large amount of bone to reach the cochlea inside the ear. To avoid removing the bone, the team developed a rigid individualized platform to allow a drill to be lined up more precisely, missing nerves that control facial functions and the tongue. Their platform should go into clinical trials this year. Even so, the team is still working on improvements, investigating whether robotics could be used for the drill’s guidance, eliminating the need to manufacture the customized platforms.

This rigid platform allows a drill to be lined up precisely for cochlear implant surgery. The slim rod demonstrates the path the drill would take.
This rigid platform allows a drill to be lined up precisely for cochlear implant surgery. The slim rod demonstrates the path the drill would take.

Webster “has a surgical mentality, meaning that he is very goal-oriented and doesn’t get bogged down in extraneous issues,” says Labadie, who also holds a doctorate in bioengineering. “Research between engineers and doctors is a team effort, but the reality is that clinical constraints, such as office hours and operating room time, restrict the available time of doctors. Bob is very respectful of this and works to make things work.”

Building The Future

In Webster’s Medical & Electromechanical Design (MED) lab, more than half a dozen student researchers work on a variety of projects. One project involves improvements to a swallowable medical robot Webster first worked on during graduate school. The next phase, Webster believes, is capsule robots that do more than provide a view inside the body.

“The best path forward is having the capsule do a clinical intervention,” Webster says. “You have a spot that’s bleeding and you apply a clip to it or a powder that causes it to clot. Or you have the capsule find the tumor and clip it off or just take a biopsy sample. That’s where I see it going.”

Critical to making that happen is solving a power-supply issue. “DC motors and batteries don’t scale down well. We need more power density,” Webster says. He’s tapped into the work of the Center for Compact and Efficient Fluid Power, a National Science Foundation-funded center in which Vanderbilt is a partner university, to help accomplish that.

Volunteer Work Plants Seeds

Webster saw early on how engineering could help make things better for patients. His father was a civil engineer who specialized in hospital construction and expansion. “He’d design the building and get the construction underway,” Webster says. The Webster family moved every few years, mostly around New York and Pennsylvania. Because young Bob was homeschooled from kindergarten through high school, he was able to focus on the math and science courses that he loved. He volunteered in a biomedical engineering department at a local veteran’s medical center. “I got to see medical equipment, how hospitals work from the inside out. Maybe that planted some seeds,” he says.

“Will it do something that doctors can’t do today? Will it be less invasive? Will it make things better for the patient?”

~ Robert Webster III

A passion for lasers led to an undergraduate degree in electrical engineering at Clemson University. He used co-ops and internships to define his career path methodically. A nuclear power plant was “all paperwork,” he discovered. The pace in a government lab was too slow. A rapidly growing corporate technology firm was somewhat appealing, but by his senior year, robotics had his attention. As an undergraduate visiting researcher at University of Newcastle, Australia, he quickly learned that he could control the robots and do the electronics, but that he was limited by what mechanical engineers built for him.

Refusing to let someone else determine his limits, Webster pursued graduate studies in mechanical engineering at Johns Hopkins. He spent the first year in the machine shop, learning to build.

“He was not afraid to get his hands dirty,” says Okamura, who also directs Johns Hopkins’ prestigious Haptics Laboratory. “Prototyping is such an important part of the design process. His enthusiasm for doing that is a key part of his success.”

Webster and his team continue to refine steerable surgical needles. This one consists of a series of telescoping precurved tubes that are flexible and can rotate inside each other.
Webster and his team continue to refine steerable surgical needles. This one consists of a series of telescoping precurved tubes that are flexible and can rotate inside each other.

For his doctoral thesis, Webster built on Okamura’s work with steerable needles. Okamura had noted that a straight needle began to bend as it penetrated the body. She and Webster launched a study to determine ways to control or use the natural bend, which has since become a major research area for Johns Hopkins; Okamura and Webster jointly hold a patent on the initial phase. Flexible needles that can be steered from outside the body could improve medical procedures, including chemotherapy, biopsies and tumor removal, with minimal trauma to the patient. Still, Webster wasn’t satisfied. Webster built a new steerable needle from a series of telescoping precurved tubes that are flexible and can rotate inside each other. This enables control of shaft shape that was not possible with the first design, which controlled only the forward trajectory of the tip. That development is also patented by Webster and Okamura.

Today, Webster works with Acoustic MedSystems, a small company based in Champaign, Ill., on a thermal treatment of liver tumors using the steerable needles. Human trials are still a few years away and work continues in the MED lab. Intuitive Surgical, a corporation that manufactures robotic surgical systems, has also licensed the patent and is developing additional initiatives in its own facilities.

The steering technology has other applications, as Robert Galloway, professor of biomedical engineering, discovered. Galloway pioneered the field of interactive image-guided surgery. Soon after arriving at Vanderbilt, Webster joined in the research, attempting to develop a laparoscopic method for image scanning before surgery; the work allows surgeons to have a three-dimensional image prior to incision.

“Prior to having Bob’s expertise, any flex in any of our objects constituted a targeting error,” Galloway says. “He brings an important piece to the next step. He understands the incredible challenges with working in engineering development for the purposes of making people better. We have a world-class team of people here who do that and so we have a high bar for acceptance of anyone new. Bob has stepped right in.”