Discovering The Source Of Back Pain

Main Category: Back Pain
Article Date: 07 Mar 2005 - 0:00 PDT

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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 - without the uncertainty, false positives and higher cost of other tests - will be completed soon.

He thinks that many physicians will begin to see the EMG, paired with an x-ray, as the first test to be performed. An MRI scan only would be done in certain circumstances, including times when the EMG and x-ray both are negative.

"The EMG is really going to help doctors to avoid unnecessary surgery and unnecessary injections because it's going to prove to them that there is nerve damage in the people who clearly have it," Haig says.

Facts about EMG, Charcot-Marie-Tooth Disorder and spinal stenosis:

� Electromyography, or EMG, was developed in the first part of the 20th century and first applied widely after World War II.

� EMG measures electrical impulses in nerves and muscle, to reveal problems in function caused by disease or physical factors.

� Charcot-Marie-Tooth Disorder affects about 150,000 Americans. It was discovered in 1886 by three physicians, Jean-Marie-Charcot, Pierre Marie and Howard Henry Tooth. According to the Charcot-Marie-Tooth Association, CMT patients slowly lose normal use of their feet/legs and hands/arms as nerves to the extremities degenerate. The muscles in the extremities become weakened because of the loss of stimulation by the affected nerves.

� Spinal stenosis - a narrowing of spaces in the spine that results in pressure on the spinal cord or nerve roots - is most common in men and women older than 50. It also may occur in younger people, however.

For more information, visit the following web sites:

U-M PM&R: Back pain
med.umich.edu/pmr/spine/infobook.htm#backpain

U-M Health Topics A-Z: EMG
med.umich.edu/1libr/tests/teste06.htm

NIAMS: Questions and answers about spinal stenosis
http://www.niams.nih.gov/hi/topics/spinalstenosis/spinal_sten.htm

Medline Plus: EMG
nlm.nih.gov/medlineplus/ency/article/003929.htm

NINDS:
Charcot-Marie-Tooth disorder

Charcot-Marie-Tooth Association
http://www.charcot-marie-tooth.org/site/content

University of Michigan Health System
2901 Hubbard St., Ste. 2400
Ann Arbor, MI 48109-2435
United States
Phone 734-764-2220
Fax 734-615-2169
med.umich.edu/opm/newspage/reporter.htm

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