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I.
Title
Imaging of Adults with Low Back Pain in the Primary Care Setting
II.
Authors –Marla Sammer, MD1
Jeffrey G. Jarvik, MD MPH2
From the Departments of Radiology1,2 Neurosurgery2, Health Services2, and the
Center for Cost and Outcomes Research2, University of Washington, Seattle,
Washington
Grant Support: Supported in part by Grant # 1 P60 AR48093 from the National Institute
for Arthritis, Musculoskeletal, and Skin Diseases
Correspondence (including reprint requests) to:
Jeffrey G. Jarvik, MD, MPH
Dept. of Radiology, University of Washington
Box 357115, 1959 NE Pacific St.
Seattle, WA 98195
Telephone: (206) 543-3320; fax (206) 543-6317; email: jarvikj@u.washington.edu
KEY POINTS
Issues
1. Lumbar spine imaging issues:
Issue 1: What is the role of imaging in patients suspected of having a herniated
disc?
Issue 2: What is the role of imaging in patients with back pain suspected of
having metastatic disease?
Issue 3: What is the role of imaging in patients with back pain suspected of
having infection?
Issue 4: What is the role of imaging in patients with back pain suspected of
having compression fractures?
Issue 5: What is the role of imaging in patients with back pain suspected of
having ankylosing spondylitis?
Issue 6: What is the role of imaging in patients with back pain suspected of
having spinal stenosis?
Issue 7: What are patients’ perceptions on the role of imaging in low back pain?
Issue 8: What is the role of vertebroplasty for patients with painful osteoporotic
compression fractures?
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IV. Key points
• The natural history of low back pain is typically benign; in the absence of “red flags”,
imaging can safely be limited to a minority of patients with low back pain
in the primary care setting. (Strong evidence)
X.
•
Low back pain imaging is often performed to rule-out a serious etiology,
especially metastases. While the first line study is plain radiographs, MR is more
sensitive. However, initial imaging with MR has not yet proven cost-effective.
(Moderate evidence)
•
Many incidental findings are discovered when imaging the lumbar spine,
including disc dessication, anular tears, bulging discs and herniated discs. Their
eventual correlation with back pain is not known. However, while disc bulges
and protrusions are common in asymptomatic individuals, extrusions are not.
(Strong evidence)
•
Imaging can diagnose surgically treatable causes of radiculopathy (herniated discs
and spinal stenosis). However, these are typically not the causes of low back pain
and are often incidental findings in asymptomatic individuals; furthermore, the
long-term efficacy of corrective surgery for these conditions has not been
established. (Moderate evidence)
•
Vertebroplasty is a promising but largely unproven therapy for patients with
painful osteoporotic compression fractures. Controlled trials need to be performed
to determine its ultimate efficacy (Insufficient evidence)
Discussion of Issues
Issue 1: What is the role of imaging in patients suspected of having a herniated disc?
Summary:
Radiculopathy is a common and well-accepted indication for imaging, however it is not
an urgent indication, and with four to eight weeks of conservative care, most patients
improve. Urgent MR and consultation are needed if the patient has signs or symptoms of
possible cauda equina syndrome (bilateral radiculopathy, saddle anesthesia, or urinary
retention). Current literature suggests that MR is slightly more sensitive than CT in its
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ability to detect a herniated disc. Plain radiography has no role in diagnosing herniated
discs, though it does, like the other modalities, show degenerative changes which are
sometimes associated with herniated discs. Finally, all three methods commonly reveal
findings in asymptomatic subjects.
Issue 2: What is the role of imaging in patients with low back pain suspected of
having metastatic disease?
Summary:
Both radionuclide studies and MR are sensitive and specific studies for detecting
metastases. We did not identify studies supporting the use of CT for detecting bony
spinal metastases, however CT does depict cortical bone well. Plain films are the least
sensitive imaging modality for detecting metastases. Nevertheless, current
recommendations still advocate using plain films as the initial imaging in selected
patients.
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Issue 3: What is the role of imaging in patients with back pain suspected of having
infection?
Summary:
When infection is suspected, MR is the imaging modality of choice. Its
sensitivity and specificity are superior to the alternatives, and the images obtained
provide the anatomical information needed for surgical planning.
Issue 4: What is the role of imaging in patients with low back pain suspected of
having compression fractures?
Summary:
There are no good estimates on which imaging modality is best for compression
fracture imaging. When differentiation between metastatic and osteoporotic collapse is
sought, MR is currently the method of choice.
Issue 5: What is the role of imaging in patients with back pain suspected of having
ankylosing spondylitis?
Summary
There are only a few studies which attempt to determine which imaging modality
is best for diagnosing ankylosing spondylitis. Plain radiographs and bone scans with
SPECT both have relatively high specificity; specificity on CT and MR is currently not
available. Plain radiographs appear to be adequate for initial imaging in a patient
suspected of having AS.
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Issue 6: What is the role of imaging in patients with back pain suspected of having
spinal stenosis?
Summary
Both CT and MR can be used to diagnosis central stenosis. On MR, the
radiologists’ general impression, rather than a millimeter measurement, is valid.
Issue 7: What are patients’ perceptions of the role of imaging in low back pain?
Summary
The majority of patients with low back pain think imaging is an important part of
their care. However, in patients who are imaged, results of satisfaction with care are
conflicting, and overall, not significantly higher in those who were imaged. Additionally,
when plain radiographs are obtained, outcome is not significantly altered (and in some
cases, is worse). But when MR or CT is used early in the work-up of low back pain,
there is a very slight improvement in patient outcome.
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Issue 8: What is the role of vertebroplasty for patients with painful osteoporotic compression
fractures?
Summary
Percutaneous vertebroplasty, first described by Galibert, Deramond et al in
1987, is the injection of polymethylmethacrylate (PMMA) into a painful vertebra, with
the intention of stabilizing it, relieving pain and restoring function. Rarely, serious
complications from bone cement leaks can occur. What is unknown is if vertebroplasty
increases the rate of adjacent vertebral fractures. Uncontrolled studies indicate that
vertebroplasty is a promising therapy for patients with painful osteoporotic compression
fractures, but confirmation by controlled trials is needed.
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