Accuracy of straight leg raise and slump tests in detecting lumbar disc herniation: a pilot study.

Abstract

OBJECTIVE To determine the accuracy of the Straight Leg Raise (SLR) and slump tests in detecting Lumbar Disc Herniation (LDH). DESIGN Cross-sectional diagnostic accuracy study. SETTING Two referral hospitals in Kigali, Rwanda: King Faisal Hospital and Centre Hospitalier Universitaire de Kigali. SUBJECTS All patients aged 18 to 70 who had an MRI and who were experiencing pain in the low back, leg or low back and leg. INTERVENTIONS Closed Magnetic Resonance Imaging (MRI) investigations for each patient as witnessed by a radiologist who read the image were recorded by the first researcher and blinded to other researchers. The SLR and slump tests were performed three times on each patient by independent testers who were blinded to the result of the first test. The test order was randomized for each subject and the two tests were separated by one day wash-out period. MAIN OUTCOME MEASURES Data were analyzed using a 2x2 table to ascertain diagnostic statistics including sensitivity and specificity with 95% confidence intervals. RESULTS Thirty three from a possible 37 patients mean age 41.58 ± 10 years completed all of the tests. The sensitivity of SLR was greater (0.875; CI: 0.690-0.957) than that of the slump tests (0.800; CI: 0.6087-0.911) (p = 0.01) in detecting LDH. The specificity for SLR was 0.429 (CI: 0.158-0.750) and for slump was 0.714 (CI: 0.359-0.918). Substantial agreement (K = 0.774) was obtained between the SLR and MRI. CONCLUSION The SLR was more accurate in detecting LDH. Further validation of this pilot finding is required by studying a larger sample.