This handy article is being
reblogged from Dr. Lienka Botha and Partners and was originally taken from www.uptodate.com. It helps us understand how imaging can help in the management of lower back pain.
What do imaging tests do?
Imaging tests create pictures of the
inside of the body. Some do this in more detail than others. In the case of low
back pain, doctors do imaging tests to try to see the structures inside the
back.
The most commonly used imaging tests
are:
■X-rays
X-rays are good at showing bones and
large internal structures. But they are not good at showing problems with “soft
tissues.” (Soft tissues include muscles and the rubbery discs found between each
of the bones in the spine.) An X-ray can show if you have bones that are broken
or out of place, or certain types of tumors or infections. X-rays are usually
done if back pain is caused by a serious injury, such as a bad fall.
■CT scans
CT scans are a special kind of
X-ray. They show more detail than X-rays, but also expose you to more radiation
and cost more. CT scans can show all the problems that X-rays show, plus some
problems with soft tissues.
■MRIs
MRIs are created using powerful
magnets. They show more detail about soft tissues than CT scans, and they do
not involve radiation. Experts think these tests are often better than CT scans
when low back pain is not improving and a test is needed. But some people can’t
have MRIs because they have devices implanted in their body that would be
affected by the magnet. Plus, MRIs are expensive and people often have to wait
to get them.
Do I need imaging if I have low back
pain?
Probably not. When people have
severe back pain, they often jump to conclusions and assume something is
terribly wrong with their back. The truth is, most cases of back pain—even
severe pain—are not caused by anything serious. Low back pain usually goes away
on its own or with simple treatment.
If you see the doctor or nurse
because of low back pain, do not ask for or expect to get an imaging test right
away, unless you have 1 of the “red flags” described below. Most people do not
need an imaging test in the first 4 to 6 weeks of low back pain. In most cases,
it does not make sense to order the test sooner, because the treatment for most
causes of low back pain during those first few weeks is the same no matter what
an imaging test might show. Even without an imaging test, your treating
physician can learn a lot about your pain by talking with you and doing an
exam.
How can the doctor tell what is
wrong without an imaging test?
If you have low back pain, your
doctor or nurse will do an exam and ask questions, such as:
■Do you have pain in just your back,
or does it spread to your buttocks or down your leg?
■Is the pain the same on both sides,
or does it affect 1 side more than the other?
■Do you have numbness, tingling, or
weakness anywhere?
■Does the pain get better when you
lean forward?
The results of the exam and your
answer to these and other questions will give your treating physician a good
idea of what is going on with your back. If you have certain “red flag” warning
symptoms (discussed below), he/she will know that there might be something
serious going on and order an imaging test.
Who should have imaging tests?
People who have had pain for 4 to 6
weeks or longer often should have imaging tests to search for the cause. People
with certain warning symptoms or traits called “red flags” should have imaging
tests done right away. This includes people who:
■Had a serious accident or injury
recently (such as a car crash or a bad fall)
■Had a less serious accident and are
older than 50
■Have back pain along with unexplained
fever or weight loss
■Take medicines called “immune
suppressants” or medicines called “steroids”
■Have a history of cancer (except
for skin cancer that isn’t melanoma)
■Use drugs that you inject, such as
heroin
■Have osteoporosis, a condition that
weakens bones
■Are older than 70
■Have leg weakness or problems
controlling their bowels or bladder
■Have a problem called “foot drop,”
which is when you cannot seem to hold your foot up, for example, while walking
Why not have imaging tests just to check?
People tend to think of imaging
tests as harmless, but they are not harmless. The X-rays doctors use to try to
diagnose back pain give as much radiation to your pelvic organs (ovaries or
testicles) as you would get from having a chest X-ray every day for more than a
year. CT scans expose you to even more radiation. Radiation is dangerous,
especially for young women who might want to have children, because it can
damage their reproductive system.
MRIs do not expose you to radiation
but they still have risks. People who have MRIs (or other imaging tests) are
much more likely to have surgery and other invasive treatments than people who
do not have imaging tests. That’s true even for people who do not need surgery.
That’s because “abnormal” findings on imaging tests of the back are very
common, even in people without back pain. Abnormal findings don’t always mean
that treatment is needed.
If your doctor does not think you
need an imaging test for low back pain, trust him or her, or ask why. Back pain
can be scary but doctors and nurses see many people with symptoms like yours
who improve with time and do not need an imaging test.
