Professor Researches Neck Pain
Dr. Beth Winkelstein’s research is a pain in the neck. Really. Winkelstein—reflective, enthusiastic, and an award-winning associate professor of bioengineering—scrutinizes the causes, prevention, and treatment of chronic neck pain.
Using a combination of biomechanical and immunologic techniques, Winkelstein and her team of researchers investigate the two common types of injuries to the cervical spine to determine how those injuries produce pain. Among the questions they’re striving to answer: What mechanisms are involved in whiplash and other painful injuries? Why do people with the same injury experience pain differently?
The adult human spine consists of 23 vertebrae: 7 in the neck area, called cervical vertebrae; 11 in the chest area, thoracic; and 5 in the lower back, lumbar. Winkelstein’s work focuses on compression injury to the cervical nerve root and tensile injury to the facet capsule ligament. Both structures are located at each cervical spinal joint. Mechanical injury to either structure may cause neck pain.
Her research aims to understand how mechanical loading translates into the physiological processes involved in neck pain. The mechanical loading mimics the clinically relevant conditions of pain in the spine and its tissues: ligaments and neural elements. The loading includes vertebral motions that can (1) compress the nerve roots that exit the spinal canal and (2) stretch the facet capsule ligament, which encloses the joints in the posterior part of the spinal column. In addition, Winkelstein says, she has models that mimic a disc herniation, which load the nerve root.
It’s known, she says, that the compression of the cervical nerve root causes a cascade of pain events. But among the many aspects of persistent neck pain that are not known is why some people who experience whiplash have pain for 10 years and some have pain for only days or weeks. It’s also unclear why women have a higher incidence of whiplash than men.
Further, Winkelstein says, some patients walk into a doctor’s office suffering excruciating pain, yet no signs of injury appear on their imaging studies, such as MRI. Often in those cases, she says, “we still don’t know the fundamental problem of what’s going on.”
The work now taking place at Winkelstein’s Spine Pain Research Laboratory, however, is expanding what had been a relatively limited knowledge of those crucial areas. “Many people are looking at pain from a clinical standpoint,” Winkelstein says. “What makes us unique is the different inputs that we apply.”
Thus, for example, what happens in the laboratory when researchers alter the magnitude of the tissue compression? As compression increases, tissue displacement increases as well. Eventually the tissue fails completely—it breaks. “You have pain as the tissue is compressed,”
Winkelstein says. “Our data show that pain occurs not only when the tissue fails; subfailure tissue injuries also produce pain.”
In vivo models form the core of Winkelstein’s research because computer modeling and research on cadavers have limitations. “Computer and cadaver modeling,” she says, “can only suggest and conjecture. Until we translate the research into physical and chemical responses, we won’t know exactly what’s going on. You can’t treat a cadaver.”
Credit: Penn Engineering Magazine, “Professor Researches Neck Pain,” by Michael J. Schwager.
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