Happenings

FAST FACT

The percentage of adults living with diagnosed and undiagnosed diabetes in the United States varies significantly by race, particularly among Hispanic and non-Hispanic Asian subgroups. New research from the U.S. Centers for Disease Control and Prevention demonstrates the particularly high rates of diabetes among individuals of Hispanic origin.

HISPANICS LIVING WITH DIABETES IN U.S. Diagnosed and Undiagnosed Mexicans 25% Puerto Ricans 22% Cubans/Dominicans 21% Central Americans 19% South Americans 12%

SOURCE: Centers for Disease Control and Prevention

Researchers at the University of Michigan (UM) have developed a biological interface that relies on the nerves in a patient’s residual limb to enable individual finger control of prosthetic devices. A team led by Paul Cederna, MD, a professor in the department of biomedical engineering, and Cindy Chestek, PhD, an associate professor of biomedical engineering, developed a technique to tap faint, latent signals from arm nerves and amplify them to enable real-time, finger-level control of a prosthesis. “This is the biggest advance in motor control for people with amputations in many years,” said Cederna, who also serves as the Robert Oneal Collegiate Professor of Plastic Surgery at the UM Medical School. “We have been able to provide some of the most advanced prosthetic control that the world has seen.” The researchers developed a methodology to separate thick nerve bundles into smaller fibers that enable precise control, and amplify the signals coming from those nerves. This is achieved via regenerative peripheral nerve interface (RPNI), or very small muscle grafts combined with machine learning algorithms. RPNIs also impede the growth of neuromoas at the severed ends of nerves, reducing residual limb pain, according to the researchers.

Because the learning happens in the algorithms instead of by prosthetic users, study subjects have been able to complete tasks using the new technology on the first try without thinking about it, says Chestek. The researchers worked with four subjects using the new biological interface coupled with the Mobius Bionics LUKE Arm. In the lab, the participants were able to pick up blocks with a pincer grasp; move their thumb in a continuous motion; lift spherically shaped objects; and play a modified version of rock-paper-scissors. “It’s like you have a hand again,” said participant Joe Hamilton. “You can pretty much do anything you can do with a real hand with that hand. It brings you back to a sense of normalcy.”

Next steps will involve implanting 12 indwelling electrodes in each of 10 participants. The research was published March 4 in Science Translational Medicine. Joe Hamilton, a participant in the University of Michigan RPNI study, naturally uses his mind to control a DEKA prosthetic hand to pinch a small zipper on a hand development testing platform.

Researchers at George Mason University, Infinite Biomedical Technologies, MedStar National Rehabilitation Hospital, and Hanger Clinic are developing a sonomyographic prosthetic system that integrates low-powered ultrasound imaging system into a prosthetic socket. Researchers at Volgenau School of Engineering at George Mason University (GMU) are developing and evaluating a prosthetic control system that integrates wearable ultrasound imaging sensors, rather than electromyography, to sense residual muscle activity. The new approach distinguishes between different functional compartments in the forearm muscles and provides robust control signals that are proportional to muscle activity.

The new sensing strategy has the potential to significantly improve functionality of upper-extremity prostheses and provide dexterous intuitive control, according to Siddhartha Sikdar, PhD, professor of bioengineering and director of the Center for Adaptive Systems of Brain-Body Interactions at GMU. The university is partnering with Infinite Biomedical Technologies as well as clinicians at MedStar National Rehabilitation Hospital and Hanger Clinic in carrying out this study.

The team predicts that the new approach will be more intuitive than myoelectric direct control and pattern recognition control and enable users to control terminal devices with more dexterity. The team’s compact, research-grade sonomyographic prosthetic system integrates a miniaturized low-power ultrasound imaging system into a prosthetic socket and leverages algorithms for real-time classification and control with multiple degrees of freedom. They will place ultrasound imaging transducers within test prosthetic sockets to complete system integration, then test the system with transradial study participants and evaluate the sonomyographic signal quality with changes in arm position and socket loading. The researchers also will assess performance of sonomyographic control compared to myoelectric direct control and myoelectric pattern recognition control. “In our preliminary work, we have demonstrated that individuals with transradial limb loss can utilize sonomyography to achieve excellent offline classification accuracy for decoding multiple degrees of freedom with minimal training,” said Sikdar. “We have also shown that sonomyography can be used to achieve precise proportional control of a target position.”

By the end of the project, the team will have a standalone prototype of a sonomyographic upper-extremity prosthesis that has been tested in laboratory settings. “The next step would be to refine and develop the prototype for take-home clinical trials in a future follow-on project,” said Sikdar. “We will work with our industry partners to develop a prototype that would be ready for commercialization.” DEADLINE EXTENDED O&P Research Proposals Due May 21 AOPA and the Center for Orthotic and Prosthetic Learning and Outcomes/ Evidence-Based Practice (COPL) are seeking proposals at two funding levels for one-time grants: $15,000 and up to two exceptional proposals for $30,000 for one year. Preference will be given to grants that address evidence-based clinical application in orthotics and prosthetics. Visit www.AOPAnet.org to view the RFP topics and guidelines or to apply online. The deadline for all proposals is May 21, 2020. Siddhartha Sikdar, PhD

VETERANS’ VIEWS Researchers Study Satisfaction Among Upper-Limb Prosthesis Users Most veterans with unilateral upper-limb loss rank satisfaction with their prosthesis at just shy of “satisfied,” regardless of the type of device, according to a study of 449 veterans. Users of myoelectric, body-powered, and cosmetic prostheses felt similarly about their componentry.

Linda Resnik, PT, PhD, FAPTA, a research career scientist at the Providence VA Medical Center, led the study. Participants were asked to describe their prosthesis, prosthetic training, device repairs, and visits to a prosthetist. They also rated their device satisfaction using two standardized measures, the Trinity Amputation and Prosthetic Experience Satisfaction Scale and OPUS Client Satisfaction With Devices Scale.

Resnik and her team expected to see greater satisfaction among myoelectric prosthesis users, but ultimately found “no differences in satisfaction by prosthesis type or terminal device.” Factors that could negatively impact satisfaction among technologically advanced prosthesis users include device fragility and unrealistic expectations, Resnik suggested. The researchers also identified lower satisfaction scores among individuals with more proximal amputation levels, younger users, and African-American users, regardless of device type.

The research team sought to identify factors linked to prosthesis satisfaction and found that initial prosthetic training is associated with greater happiness, and noted that occupational or physical therapy can play a critical role in the early stages of prosthetic care. “Data shows that some people don’t receive training to use their device,” said Resnik. “When that happens, patients don’t incorporate their device into their daily lives … . They become frustrated and are set up for a bad experience.” The full results were published online in January in Prosthetics and Orthotics International.

CODING CORNER DME MACs Make Revisions to AFO/KAFO Policy The four durable medical equipment Medicare administrative contractors (DME MACs) released a revised version of the Ankle-Foot Orthosis/ Knee-Ankle-Foot Orthosis (AFO/ KAFO) Local Coverage Determination (LCD) and Policy Article (PA). Many of the revisions were clerical in nature, such as changing “ordering physician” to “treating practitioner” and updating the policy with the standard written order instructions.

However, the PA did contain some significant revisions, including updating its coding guidelines for the L1906 and introducing new coding guidelines for 16 AFOs: L1900, L1902, L1904, L1907, L1910, L1920, L1930, L1932, L1940, L1945, L1950, L1951, L1970, L1971, L1980, and L1990. The LCD and PA also updated the code descriptor of L2006 based on a recent quarterly update from the Healthcare Common Procedure Coding System. The new code descriptor for L2006 is: “Knee, ankle, foot device, any material, single or double upright, swing and stance phase microprocessor control with adjustability, included all components (e.g., sensors, batteries, charger), any type activation, with or without ankle joint(s), custom fabricated.” The previous code descriptor read, “Swing and/or stance phase microprocessor control.” Visit the CMS website for details.

AOPA’s Coding & Reimbursement Committee is reviewing the new and revised AFO coding guidelines and will provide the DME MACs with appropriate recommendations if necessary.

14 APRIL 2020 | O&P ALMANAC PHOTOS: Getty Images