Determination of Sensitivity and Specificity of Straight Leg Raise Test Via Transforaminal Nerve Root Block

Marmara University88 enrolled

Overview

This study aims to evaluate the diagnostic accuracy of the straight leg raise test in patients with suspected lumbosacral radicular pain. Lumbosacral radicular pain is often caused by lumbar disc herniation and may radiate from the lower back or buttock to the leg. Although the straight leg raise test is commonly used in clinical practice, its diagnostic performance has been reported to vary. In this study, diagnostic transforaminal epidural steroid injection or selective nerve root block will be used as the reference standard. The sensitivity, specificity, likelihood ratios, and area under the curve of the straight leg raise test will be calculated. The findings may help guide clinicians in determining when the straight leg raise test is sufficient and when further diagnostic confirmation may be needed.

Low back pain is one of the leading causes of disability worldwide. Lumbosacral radicular pain is commonly caused by lumbar disc herniation and is characterized by pain radiating from the lower back or buttock to the leg in a dermatomal distribution. The straight leg raise test is a simple and widely used physical examination test for evaluating suspected lumbar radiculopathy; however, its diagnostic accuracy varies across studies. This study aims to evaluate the diagnostic performance of the straight leg raise test in patients with suspected lumbosacral radicular pain. Diagnostic transforaminal epidural steroid injection or selective nerve root block will be used as the reference standard. Only technically selective injections performed without sedation and with a low volume of short-acting local anesthetic will be included in the analysis. The study will assess the sensitivity, specificity, likelihood ratios, and area under the curve of the straight leg raise test. The results may help clarify when the straight leg raise test is reliable on its own and when additional diagnostic confirmation may be needed for clinical decision-making.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Lumbosacral Radicular Pain

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age between 18 and 65 years. * Preliminary diagnosis of lumbar radicular pain based on medical history, physical examination, and lumbar magnetic resonance imaging. * Patients scheduled to undergo transforaminal epidural injection targeting the L4, L5, or S1 nerve root. Exclusion Criteria: * Inability to access clinical or procedural records in the hospital system. * Absence of available radiological records related to the target level, if required. * Inability to provide reliable NRS or straight leg raise test assessment due to cognitive impairment or language barrier. * Coagulopathy, defined as INR \> 1.5 or platelet count \< 80,000/mm³, or inability to discontinue anticoagulant or antiplatelet therapy when required. * Local or systemic infection, or skin lesion at the planned injection site. * Pregnancy or breastfeeding. * Known severe hypersensitivity to iodinated contrast material or local anesthetics. * Progressive neurological deficit or cauda equina syndrome. * Bilateral or nearly bilateral pain with both sides being prominent and equivalent, or need for therapeutic injection at more than one level during the same session. * Epidural injection with local anesthetic and/or steroid at the same level within the last 6 weeks. * Active polyneuropathy or other diffuse neuropathies. * Active radicular pain originating from nerve roots other than L4, L5, or S1. * Requirement for mandatory sedation.

Outcomes

Primary Outcomes

Diagnostic Performance of the Straight Leg Raise Test

The diagnostic performance of the straight leg raise test will be evaluated in patients with suspected lumbosacral radicular pain using diagnostic transforaminal epidural steroid injection as the reference standard.

Time frame: Before and 1 hour after diagnostic transforaminal epidural steroid injection.

Secondary Outcomes

Change in Pain Intensity Assessed by Visual Analog Scale

Pain intensity will be assessed using the Visual Analog Scale, which ranges from 0 to 10, with higher scores indicating greater pain intensity. Pain intensity will be measured before and 1 hour after diagnostic transforaminal epidural steroid injection. The change in Visual Analog Scale score after the diagnostic intervention will be evaluated in patients with suspected lumbosacral radicular pain.

Time frame: Before and 1 hour after diagnostic transforaminal epidural steroid injection.

DN-4 Quastionnaire

The DN-4 (Douleur Neuropathique en 4 Questions) is a brief and reliable screening questionnaire used to determine whether a patient's pain is of neuropathic origin. It consists of a total of 10 items. Its name, DN-4, derives from the fact that it includes 4 main sections. Seven of the questions relate to patient-reported sensory symptoms, while three are based on clinical examination findings. Each "yes" response scores 1 point, yielding a total score ranging from 0 to 10. A score above 4 indicates a high likelihood of neuropathic pain.

Time frame: Before diagnostic transforaminal epidural steroid injection

Intervertebral Disc Degeneration Assessed by Pfirrmann Grading Scale

Intervertebral disc degeneration will be evaluated using the Pfirrmann grading scale on lumbar magnetic resonance imaging. The Pfirrmann grading scale ranges from grade I to grade V, with higher grades indicating more severe intervertebral disc degeneration. Pfirrmann grades will be evaluated in relation to clinical findings, straight leg raise test results, pain intensity, and response to the diagnostic intervention in patients with suspected lumbosacral radicular pain.

Time frame: Using available lumbar magnetic resonance imaging obtained before or after the diagnostic intervention, up to November 1, 2026

Diagnostic Performance of the Bragard Test

The diagnostic performance of the Bragard test will be evaluated in patients with suspected lumbosacral radicular pain. The Bragard test will be assessed before and 1 hour after diagnostic transforaminal epidural steroid injection, using the response to the diagnostic intervention as the reference standard.

Time frame: Before and 1 hour after diagnostic transforaminal epidural steroid injection

Nerve Root Compression Grade on Lumbar Magnetic Resonance Imaging

The degree of nerve root compression will be evaluated on lumbar magnetic resonance imaging in patients with suspected lumbosacral radicular pain. Nerve root compression grade will be assessed in relation to straight leg raise test results, Bragard test results, pain intensity, and response to diagnostic transforaminal epidural steroid injection.

Time frame: Using available lumbar magnetic resonance imaging during the study period, up to November 1, 2026