Associations between patient report of symptoms and anatomic impairment visible on lumbar magnetic resonance imaging

Study Design. A cross-sectional study comparing the relationship of symptom s with anatomic impairment visible on lumbar magnetic resonance imaging in 408 symptomatic subjects. Objective. To determine how various anatomic impairments, including the mag nitude and location of nerve compression visible on lumbar magnetic resonan ce imaging, are associated with patient reports of pain, weakness, and dyse sthesia. Summary and Background Data. Anatomic impairments of the intervertebral dis c, radicular canal, and associated soft tissues are prevalent in people wit h and those without low back pain or lower extremity radiculopathy. This ha s led to confusion in differentiating between symptom generators and benign variation visible on lumbar magnetic resonance imaging. Recent literature has suggested that the presence of nerve compression is an important findin g in the prediction of symptoms. However, the threshold for meaningful nerv e compression has not been described. Methods. In this study, 408 participants undergoing a diagnostic workup for low back pain, radiculopathy, and/ or completed a survey and pain drawing. Participants underwent standardized lumbar magnetic resonance imaging usin g a 1.5-T scanner. Two classification systems describing the spatial distri bution of symptoms were developed. An additional system to quantify the mag nitude of nerve and thecal sac compression was created. All systems were as sessed for reliability, after which comparisons among variables were perfor med using X-2 as well as simple and multiple logistic regression analysis. Results. The reliability coefficients for categorizing patients on the basi s of pain drawing ranged from 0.75 to 0.88. The S1-S2 segmental distributio n was the most commonly reported location of symptoms, followed by L4-L5, T he most common magnetic resonance imaging diagnosis was "unremarkable," fol lowed by "disc impairment without nerve compression." Disc extrusion was pr esent in 10.8% of participants. The reliability of classifying nerve compre ssion visible on magnetic resonance imaging ranged from 0.27 to 1. Nerve co mpression was present in 37% of participants, and 18% had severe nerve comp ression. There were no significant associations between segmental distribut ion of symptoms and the presence of anatomic impairment. However, according to a collapsed classification scale, severe nerve compression and disc ext rusion were predictive of pain distal to the knee (odds ratios, 2.72 and 3. 34). The self-report of weakness was associated mildly with severe nerve co mpression and disc extrusion, but not with other findings. Magnetic resonan ce imaging findings did not predict self-reports of dysesthesia. Conclusions. The presence of disc extrusion and/or ipsilateral, severe nerv e compression at one or multiple sites is strongly associated with distal l eg pain. Mild to moderate nerve compression, disc degeneration or bulging, and central spinal stenosis are not significantly associated with specific pain patterns. Although segmental distributions of pain can be determined r eliably from pain drawings, this finding alone is of little use in predicti ng lumbar impairment. The self-report of lower extremity weakness or dysest hesia is not significantly related to any specific lumbar impairments.