Discovering The Source of Back Pain
EMG testing can provide answers that MRI can't, U-M Health System physician says
ANN ARBOR, MI - Carolyn Koski suffered for years from symptoms of a disorder nobody knew she had. Her doctors knew something was wrong with her, and all signs pointed to spinal stenosis, a narrowing of the passages, such as the spinal canal and the spaces between vertebrae, through which spinal nerves pass. She had weakness and numbness in her legs, she had problems with dizziness and fatigue, and an MRI scan showed a tight, small canal that indicated spinal stenosis in addition to two herniated disks. She probably would need surgery.
But in Koski's case, the obvious answer turned out not to be the right answer. She volunteered for a University of Michigan Health System study that examined an alternative kind of testing. Doctors performed an electromyography (EMG) test, which involves putting a needle into a patient's muscles and listening to the messages the brain sends to the muscles.
They discovered that she had Charcot-Marie-Tooth, an inherited neurological disorder characterized by a slowly progressive degeneration of the muscles in the foot, lower leg, hand and forearm. Without treatment, the condition gets worse and worse as patients age.
"By having the EMG," Koski says, "I was able to avoid surgery. I was able to get answers for questions that weren't answerable before." She now is being treated for the nerve disorder.
Nobody in Koski's 59 years had diagnosed the nerve disorder prior to that testing at the U-M Health System, and the diagnosis was made possible through the use of the EMG, says Andrew Haig, M.D., associate professor in the Department of Physical Medicine and Rehabilitation at the U-M Health System.
"It would never, ever show up on an MRI scan," Haig says. "These kinds of diseases only show up on an EMG test."
Haig says both kinds of tests have their strengths, and a current study at U-M is looking at the MRI scan and EMG test to find out which one "really fits better in relationship to your back pain."
An MRI is a photograph, like a picture of your car, Haig explains. An EMG is a test of the physiology and can show whether or not a person has nerve damage. "It's like putting a key in your car and seeing whether the engine works and seeing whether the radio plays," he says.
Haig's study of whether EMG allows doctors to zoom in on the exact location where back pain originates