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 .
The Diagnostic Accuracy of Magnetic Resonance Imaging, Work Perception, and Psychosocial Factors in Identifying Symptomatic Disc Herniations
Study Design This was a prospect i ve study of patients ( study group ) with symptomatic disc herniations and asymptomatic volunteers ( control group ) matched for age , sex , and work-related risk factors . Objective To determine the prevalence of disc herniation in a matched group of asymptomatic volunteers and to access the diagnostic accuracy of magnetic resonance imaging , work perception , and psychosocial factors in identifying symptomatic disc herniations . Summary of Background Data Disc herniations have been reported to occur in 20–36 % of asymptomatic volunteers . A valid comparison of asymptomatic individuals and patients with disc herniations has not been performed . Methods Forty-six patients with low back pain and sciatica severe enough to require a disceclomy were compared with 46 age- , sex- , and risk factor-matched ( heavy lifting , twisting and bending , vibration , and sedentary activity ) asymptomatic voluteers .  Both groups had a complete clinical and magnetic resonance imaging examination and completed a question naire to assess differences in the psychosocial and work perception profiles . The prevalence and the severity of morphologic alterations ( disc herniation , disc degeneration , and neural compromise ) was analyzed by two independent radiologists in a blinded fashion . Differences between both groups regarding MRI findings , work perception ( occupational mental stress , intensity of concentration , job satisfaction , and job-related resignation ) and psychosocial factors ( anxiety , depression , self-control , social support , and marital status ) were compared using multivariate techniques . Stepwise discriminate analysis was used to identify the best discriminating variables within the magnetic resonance image , work perception , and psychosocial categories in terms of the diagnostic accuracy to predict group membership ( study [ pain ] or control [ no pain ] group ) . Results Matched controls had significantly more risk factors than a group of normal individuals . The present study has presented evidence that an age- , gender- , and occupational risk factors-matched group of asymptomatic patients shows a high incidence rate of disc herniations ( 76 % ) . Although significantly less than the symptomatic group incidence of 96 % , this represents a much higher prevalence rate than generally expected and reported in other studies of unmatched asymptomatic volunteers . Patients had more severe disc herniations ( disc extrusions ) than asymptomatic volunteers ( 35 % vs. 13 % ) . There was no significant differences regarding disc degeneration between both groups ( 96 % vs. 85 % ) . The only substantial morphologic difference between both groups was the presence of a neural compromise ( 83 % vs. 22 % ) , which was highly significant ( P < 0.0001 ) . There were significant differences between both groups regarding work perception ( occupational  mental stress , intensity of concentration , job satisfaction , and resignation ; P<0.027 ) and psychosocial factors ( anxiety , depression , self-control , marital status ; P<0.0001 ) . The best single predictor of a group membership was the extent of neural compromise . A combination of this factor with occupational mental stress , depression , and marital status was the best predictive model . With this model , the false-negative rate ( potential overtreatment of disc morphology ) was reduced by more than half compared with morphologic factors ( nerve root compression ) alone ( 22 % vs. 11 % ) . Conclusions . In an age- , sex- , and risk factormatched group of asymptomatic individuals , disc herniation had a substatially higher prevalence ( 76 % ) than previously reported in an unmatched group . Individuals with minor disc herniations ( i.e. , protrusion , contained discs ) are at a very high risk that their magnetic resonance images are not a causal explanation of pain because a high rate of asymptomatic subjects ( 63 % ) had comparable morphologic findings . The only highly significant difference between the study group and control group regarding morphologic findings was the criteria of a nerve root compromise . Work perception and psychosocial factors were helpful in discriminating between symptomatic and asymptomatic disc herniations
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 .