December 2010 Issue
Clinicians and scientists from Europe and the United States gathered on November 3 for Neuroprosthetics 2010, a one-day, international symposium organized by the Worcester Polytechnic Institute (WPI) Bioengineering Institute, Massachusetts. These experts, who are at the forefront of research and development of next-generation implantable artificial limbs, discussed the goals, challenges, and progress of their R&D efforts.
The morning and afternoon session each began with a keynote speaker: Col. Jennifer Menetrez, MD,founding director of the Center for the Intrepid (CFI), Brooke Army Medical Center (BAMC), San Antonio, Texas; and Kendra Calhoun, president and CEO of the Amputee Coalition of America (ACA), respectively, shared a common message that prosthetic devices exist to enhance people's quality of life. Menetrez and Calhoun challenged researchersto think about how their ideas and inventions translate into products and to move toward greater functionality for military and mainstream prosthesis wearers alike.
"Think about the purpose of the device that you are making for the patient," Menetrez said. "Think about what the patient wants to do. What is it going to be able to do from a functional standpoint? What does it do that other prostheses out there can't?"
The morning session focused on recent developments in osseointegration (OI); the soft tissue seal as a key to preventing infection was a recurring theme. This goal has not yet been accomplished, according to morning-session speaker, Roy Bloebaum, PhD, research professor for the Department of Orthopaedics, University of Utah, Salt Lake City. Bloebaum said that due to infection rates and implant design issues, human trials for OI in the United States are approximately five years out. He said that his team continues to work with sheep modeling to ensure the stability of the skin/implant interface.
Horst Aschoff, MD, head of the Department for Plastic, Hand, and Reconstructive Surgery, SANA-Clinics in Luebeck, Germany, discussed his more than ten years of experience studying and working with endo-exo transfemoral implant patients. Aschoff said that in June 2009, he performed the first endo-exo tibia implant surgery, which, according to the patient's Netherland-based physicians, still performs to the patient's expectations.
Gordon Blunn, PhD, head of the John Scales Centre for Biomedical Engineering, University College London, England, shared his research on intraosseous transcutaneous amputation prostheses (ITAP). "The discerning features of ITAP [as compared to OI] is that it relies on soft tissue attachment to prevent infection, which leads to implant failure," Blunn said. The ITAP technology is already being used clinically in the United Kingdom to treat amputees, some of whom are returning war wounded, Blunn noted.
The OI session concluded with Wolfgang Plitz, MD, PhD, Laboratory of Biomechanics and Experimental Orthopedics, Großhadern Clinic, University of Munich, Germany, who presented the biomechanical aspects and test results for a new tripod-shaped implant fabricated from spongiosa metal with titanium-a material that is supposed to minimize infection risk.
The afternoon sessions focused on regenerative soft tissue: how and why soft tissue regenerates, how it integrates, and how it supports the prosthetic device. Raymond Page, PhD, research assistant professor, WPI Bioengineering Institute, Department of Biology & Biotechnology, said that he and his team have had promising results with muscle regeneration in mice using stem cells. Christopher Lambert, PhD, research associate professor at WPI Bioengineering Institute, believes he and his team can "offer the ability to modify surfaces so that you can get true biocompatibility between the tissue and implant," he said. Finally, Stephen Lambert, PhD, associate professor of medicine at the Central University of Florida, Orlando, is researching "the ability to reconstruct neural circuits essentially in silicone," he said, with the ultimate goal of integrating neural components with a prosthetic device so the patient can move a prosthesis in response to a thought and receive sensory feedback.
A date for Neuroprosthetics 2011 has not been set, but according to WPI, plans for the 2011 symposium will begin in the near future.