Laboratory Studies
Laboratory tests generally are not helpful in the diagnosis of lumbar disc disease.
Indications for screening laboratory examinations include pain of a nonmechanical nature, atypical pain pattern, persistent symptoms, and age greater than than 50 years.
Laboratory may include the following to rule out other disease:
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Complete blood count (CBC) with differential
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Erythrocyte sedimentation rate (ESR)
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Alkaline and acid phosphatase level
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Serum calcium level
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Serum protein electrophoresis
Imaging Studies
Radiographic studies are very helpful in the diagnosis of lumbar disc disease, [8] but several important caveats should be taken into account with the use of these tests. [9] The American College of Radiology Appropriateness Criteria does not recommend imaging studies for uncomplicated acute low back pain. [10]
Most patients with pain from lumbar disc disease have resolution of their symptoms with conservative treatment.
For an otherwise healthy individual, unless the patient is immobilized completely by the pain and requires admission or the pain has been present for more than 6 weeks, diagnostic studies are not recommended. Elderly patients or those with a history of cancer or chronic infection (including tuberculosis), trauma, or osteoporosis should have imaging studies performed as part of their routine workup during initial presentation.
MRI is the imaging modality of choice in evaluating patients with lumbar disk disease. [6, 10] Studies have shown that as many as 60% of people without back symptoms have disk bulges and protrusions on MRI. [11] Therefore, these findings may not correlate with the patient's symptoms. [12]
In a study of 283 patients with sciatica with confirmed disc herniation, MRI assessment of nerve root compression and extrusion of a herniated disc was associated with less leg pain at 1-year follow-up. However, according to the study, MRI findings seemed not to be helpful in determining which patients would do better with early surgery versus prolonged conservative care. [12]
CT scanning is useful for diagnosing disc disease but is less sensitive than MRI. CT scanning of the abdomen can help evaluate and rule out other etiologies of pain, such as aortic aneurysm, ureteral calculi, and intra-abdominal causes. Combining CT scan with myelography can increase the sensitivity of the modality for spinal cord pathology.
Myelography may provide a definitive diagnosis on its own, but this is an invasive test requiring a lumbar puncture and the use of contrast material.
Plain films of the lumbar spine are generally not helpful in the diagnosis of lumbar disc disease, except to rule out other diseases and to evaluate for possible skeletal etiology as the cause of the patient's symptoms. They should be performed in patients who are elderly or in those with a history of cancer or chronic infection (including tuberculosis), trauma, or osteoporosis.
Technetium-99m-labeled phosphorus indicates active mineralization of bone. A bone scan is indicated to rule out tumors, trauma, or infection.
