Nerve root sedimentation sign for spinal stenosis assessed

(HealthDay)—The nerve root sedimentation sign (SedSign), seen on magnetic resonance images, can differentiate lumbar spinal stenosis (LSS) from asymptomatic controls, according to a study published in the Nov. 15 issue of Spine.

Christy C. Tomkins-Lane, Ph.D., from Mount Royal University in Calgary, Canada, and colleagues examined the sensitivity and specificity of the SedSign in a retrospective study involving three blinded raters who independently reviewed magnetic resonance images from 67 subjects with clinically diagnosed LSS confirmed on imaging by a spine specialist; 31 people with low back pain (LBP) but no LSS; four people with severe vascular claudication; and 46 asymptomatic participants.

The researchers found that inter-rater reliability ranged from 0.62 to 0.69 and intrarater reliability for the sign ranged from κ = 0.87 to 0.97. Sensitivity and specificity ranged from 42 to 66 percent and 49 to 78 percent, respectively. Inclusion of images with only a smallest cross-sectional area of the dural sac <80 mm² improved sensitivity to a range of 60 to 96 percent. SedSign could differentiate between LSS and asymptomatic controls (P = 0.004) but was not able to differentiate between LSS and LBP or between LSS and vascular claudication.

"The sign seems most sensitive in defining severe LSS cases and yet may not add any specific diagnostic information beyond the traditional history, physical examination and imaging studies that are standard in LSS diagnosis," the authors write.

Relevant financial activities outside the submitted work included expert testimony and payment for lectures.

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