MRI findings of disc protrusion , nerve root displacement or compression , disc degeneration , and high intensity zone are all associated with LBP , but individually , none of these abnormalities provides a strong indication that LBP is attributable to underlying pathology .
This limits their value in refining epidemiological case definitions for LBP
OBJECTIVE to assess how confidently  low back pain ( LBP ) can be attributed to abnormalities on magnetic resonance imaging ( MRI ) , and thereby explore the potential value of MRI abnormalities in refining case definition for mechanical LBP in epidemiological research .
SUMMARY OF BACKGROUND DATA most epidemiological studies of mechanical LBP have defined cases only by reported symptoms , but it is possible that the potency of causes differs depending on whether there is demonstrable underlying spinal pathology .
Magnetic resonance imaging of the lumbar spine in people without back pain.
BACKGROUND The relation between abnormalities in the lumbar spine and low back pain is controversial . We examined the prevalence of abnormal findings on magnetic resonance imaging ( MRI ) scans of the lumbar spine in people without back pain . METHODS We performed MRI examinations on 98 asymptomatic people . The scans were read independently by two neuroradiologists who did not know the clinical status of the subjects . To reduce the possibility of bias in interpreting the studies , abnormal  MRI scans from 27 people with back pain were mixed r and omly with the scans from the asymptomatic people . We used the following st and ardized terms to classify the five intervertebral disks in the lumbosacral spine : normal , bulge ( circumferential symmetric extension of the disk beyond the interspace ) , protrusion ( focal or asymmetric extension of the disk beyond the interspace ) , and extrusion ( more extreme extension of the disk beyond the interspace ) . Nonintervertebral disk abnormalities , such as facet arthropathy , were also documented . RESULTS Thirty-six percent of the 98 asymptomatic subjects had normal disks at all levels . With the results of the two readings averaged , 52 percent of the subjects had a bulge at at least one level , 27 percent had a protrusion , and 1 percent had an extrusion . Thirty-eight percent had an abnormality of more than one intervertebral disk . The prevalence of bulges , but not of protrusions , increased with age . The most common nonintervertebral disk abnormalities were Schmorl 's nodes ( herniation of the disk into the vertebral-body end plate ) , found in 19 percent of the subjects ; annular defects ( disruption of the outer fibrous ring of the disk ) , in 14 percent ; and facet arthropathy ( degenerative disease of the posterior articular processes of the vertebrae ) , in 8 percent . The findings were similar in men and women . CONCLUSIONS On MRI examination of the lumbar spine , many people without back pain have disk bulges or protrusions but not extrusions . Given the high prevalence of these findings and of back pain , the discovery by MRI of bulges or protrusions in people with low back pain may frequently be coincidental
MRI findings of disc protrusion , nerve root displacement or compression , disc degeneration , and high intensity zone are all associated with LBP , but individually , none of these abnormalities provides a strong indication that LBP is attributable to underlying pathology .
This limits their value in refining epidemiological case definitions for LBP
OBJECTIVE to assess how confidently  low back pain ( LBP ) can be attributed to abnormalities on magnetic resonance imaging ( MRI ) , and thereby explore the potential value of MRI abnormalities in refining case definition for mechanical LBP in epidemiological research .
SUMMARY OF BACKGROUND DATA most epidemiological studies of mechanical LBP have defined cases only by reported symptoms , but it is possible that the potency of causes differs depending on whether there is demonstrable underlying spinal pathology .