Accuracy of Straight Leg Raising Test in the Clinical Diagnosis of Lumbar Disc Herniation

Open Access

Abstract

Background: Low back pain is a common reason for medical consultation, though only 1–3% of cases result from lumbar disc herniation. Despite MRI being the diagnostic gold standard, its high cost and limited availability in Bangladesh restrict routine use. The straight leg raising (SLR) test is a simple clinical tool for suspected lumbar disc herniation, but its diagnostic accuracy varies widely across studies. Therefore, this study aimed to evaluate the diagnostic accuracy of the SLR test in the clinical diagnosis of lumbar disc herniation. Methods & Materials: This cross-sectional observational study was carried out in the Department of Neurosurgery, Bangabandhu Sheikh Mujib Medical University, Dhaka, from October 2016 to April 2018. Ninety patients with low back pain and unilateral or bilateral sciatica were included. Following clinical evaluation, the straight leg raising (SLR) test was performed in the supine position, with pain below 70° considered positive. MRI of the lumbosacral spine served as the reference standard. Data were analyzed using SPSS version 23, and sensitivity, specificity, predictive values, accuracy, Fisher’s exact test, and ROC analysis were calculated, with p < 0.05 considered statistically significant. Results: The mean age was 40 ± 11.1 years, with male predominance (2.2:1). Disc herniation most commonly involved the L4–L5 level (54.9%). The SLR test demonstrated sensitivity 87.8%, specificity 75.0%, positive predictive value 97.3%, negative predictive value 37.5%, and overall accuracy 86.7%. A significant association was found between SLR results and MRI findings (p < 0.05). Conclusion: The SLR test is a reliable clinical tool for diagnosing lumbar disc herniation, while MRI may be reserved for confirmation, especially when surgery is planned.