Rehabilitation Medicine Department researcher Arin Ellingson, PhD, has been fascinated by the spine for a long time. He took all the math and technical education courses he could in high school and then advanced to biomechanics in college. After completing his PhD program in biomedical engineering at the U of M and a post-doctoral fellowship at Mayo Clinic, he is now focused on detecting biomechanical and imaging-based biomarkers of spinal health.

“The spine is especially interesting because it has diametrically opposed roles: it needs to provide neurological protection for the spinal cord and nerve roots, and it also needs to enable large, controlled motion,” he said. “I want to fundamentally understand how the spine can accomplish these contradictory tasks, and to understand how abnormalities might be related to different conditions.”

Biometric tools/assessments

Arin Ellingson, PhD

Ellingson (pictured here) was drawn to physical medicine and rehabilitation because he likes to develop biometric tools and assessments to help evaluate spinal health, primarily from a motion standpoint. “I fit in really well in a clinical department because I have a unique skillset,” he said. “It’s really in collaborating with our clinical partners that we can identify new areas that need to be studied, then use advanced quantitative approaches to assess those areas.”

Developing those biometric tools to enable clinicians to make differential diagnoses of the neck and spine — looking at the range of disorders that could be causing a patient’s symptoms – is extremely difficult. “There are numerous factors involved,” explained Ellingson. “If you look at spinal disorders, they can be caused by disc degeneration, other bone and ligament pathology, neural tissue that becomes impinged, neuromuscular control abnormalities, as well as a host of psychosocial issues such as chronic pain syndrome.”

Uphill battle
While Ellingson realizes this will be an uphill battle, the worldwide prevalence of spine and neck pain makes it worth doing. “Our lab’s goal is to identify biomarkers of spinal health,” he said. “We’re interested in identifying spinal instability and signs of abnormal motion by integrating kinematics and imaging techniques. We try to do this on a segmental level – how each bone of the spine moves in relationship to the others.” Ellingson's lab team includes Rebecca Abbott, post-doctoral associate; Matthew MacEwen, Biomedical Engineering PhD student; Mary Foltz, Rehabilitation Science PhD student; and Craig Kage, Rehabilitation Science PhD student/physical therapist.

The University of Minnesota provides an incredibly rich environment within which to do this work. “The primary reasons I came here six years ago are the resources available and the potential for collaboration,” said Ellingson. “For example, I do a lot of MRI-based research. The U’s Center for Magnetic Resonance Research is world renowned and has unparalleled capabilities. In addition, the people here are amazing to work with. I collaborate with a wide group of clinicians, as well as with researchers in the Departments of Orthopedics, Radiology, and Engineering. We’re also doing some new work with the College of Veterinary Medicine and the Stem Cell Institute.”

Powerful tool
To capture the spinal movements that will help them quantify biomarkers, Ellingson and his research team also have access to a powerful research tool known as biplane video radiography. The system includes two dynamic x-ray systems that rotate around a patient to provide simultaneous front and side views of their anatomy. In the photo above, Abbott is simulating a participant aligned for biplane videoradiography collection, MacEwen is putting retroreflective markers on her head to track global head-to-torso motion using the motion capture system, and Ellingson is aligning the x-ray source to image Abbott's cervical spine motion using the biplane videoradiography. “The stereographic images enable us to see how each segment of the spine moves during weight-bearing activities,” said Ellingson. “There are less than 30 of these systems across the country.”

Ellingson and his team are using all the University’s resources to better understand the biomechanics of back pain. “We’re hoping that some of the biomarkers we’re able to identify can be used for future patient differentiation, which enables better clinical studies, and ultimately, to develop better treatments,” he said. “They could also help evaluate the efficacy of current and emerging treatments, whether it’s conservative rehab approaches or emerging biological therapies such as stem cell treatments or biochemical injections.”

Assessing treatment mechanisms
Ellingson and his research team want to fundamentally understand the mechanisms of rehabilitation treatments. “If the patient is getting better or worse, we want to understand why,” he said. “What are we actually changing when a provider does a mobilization — what is it doing to the spine and how does it alter that patient’s ability to move in a pain-free way? We want to be able to assess these mechanisms to explain how they’re improving the patient’s wellbeing.”