New views on long-term pain

Award-winning research helps students think holistically about pain-generating circuits

By Greg Scheiderer

Work under way at the university is giving therapists new ways to diagnose and treat people suffering from chronic pain.

Roger Allen, assistant professor of physical therapy at Puget Sound, and a team of nine master’s students conducted the research, successfully treated patients at the university clinic, published abstracts on the work in the journal Neurology Report and presented their findings at a conference of the American Physical Therapy Association.

Allen said they were clued to their findings through work with a patient who had cancer and who also suffered from chronic pain in her upper arm. When therapists work with chronic pain sufferers they look at two basic "maps" that lead them from the area of pain to its likely sources. In this case the maps led to dead ends in the treatment of the patient, and her pain continued.

Often in such cases therapists start looking for psychological causes of pain, but Allen persisted. Eventually, it was discovered that the cancer had damaged a nerve that controlled blood flow in the woman’s arm, and the restricted flow led to the pain. For Allen, and the patient, it was a welcome lesson.

Allen and the students set out to draw a new map. For the study they selected six nerves that control blood flow to the arm and hand. One by one they blocked those nerves in study subjects and then looked at the results with a device called a digital liquid crystal thermogram, which shows changes in skin temperature.

"If we blocked the nerve effectively, then the nerve was no longer constricting the arteries and the arteries would be dilated," explained Allen. "You get a lot of blood flow to the area and you can see it on the thermogram."

The multicolored thermograms translated into a new map, the first ever map of vascular innervation patterns to the arms, and it was not the same as the maps for normal touch sensation.

"This map is similar," said Allen, "but there are a few salient differences that to a clinician might make the difference. With one the pain may not really add up. The other would help you determine if it’s vascular, or neurovascular."

Allen said the research isn’t really a medical breakthrough.

"It does offer a new perspective on long-term pain which will help relieve a great deal ofhuman suffering in the future," he added. "It may help us explain situations that were inexplicable before, help avoid misdiagnoses and tell us how to treat people." That was the case with their original patient. They were able to treat the pain in her arm, though cancer soon claimed her life.

Allen says the new research has had an effect in the classroom as well as the clinic.

"What we’re trying to teach our students now is to think about pain-generation circuits," Allen said. "The most important information from the patient is where they feel the pain. But you can’t limit your thoughts by thinking that’s where the problem must be. It could be anywhere between where the patient feels it, all the way up the nervous system into the brain."

Further, Allen feels clinicians should not feel that what they learn in school is the final word, because new things are discovered every day.

"I tell the students that if they take the attitude that, ‘Hey, I know what’s going on,’ they just stopped their learning. How ready is that person to learn the next new findings as those ideas come out?"

The work earned Allen the Dirk Andrew Phibbs Memorial Award from the University Enrichment Committee. Former Puget Sound President Phillip Phibbs and his wife Gwen established an endowment in memory of their son for the purpose of supporting faculty research and travel. The fund helped Allen and the students with their study and presentation. The committee singles out faculty for the award from among those supported by the fund.