Low back pain is common, but the evaluation must quickly separate benign mechanical pain from serious pathology and then identify the most likely pain generator. This page provides a structured approach you can use in clinic: red flags → targeted history → examination → neurological assessment → special tests.
Step 1: Screen for Red Flags First
Before detailed testing, identify features that change urgency, investigations, and referral pathways.
Red Flags to Act On
- Major trauma
- Suspected tumor / malignancy
- Suspected infection
- Suspected fracture
- Neurological deficits
- Autonomic symptoms (e.g., bladder/bowel concerns)
- Motor deficit
- Sensory deficit
- Severe, disproportionate, or rapidly escalating pain
Clinical implication: Any red flag should shift your evaluation toward urgent imaging, labs, specialist input, or emergency referral, depending on the scenario.
Step 2: Clarify the Likely Cause and Pain Generator
A high-yield back pain evaluation aims to answer:
- Is this potentially serious?
- Is it radicular, stenotic, SI joint–mediated, myofascial, or mechanical?
- What is the most probable pain generator?
Common Pain Generator Buckets
- Disc / annulus / endplate-related pain
- Facet joint–mediated pain
- Nerve root irritation / radiculopathy
- Central canal or foraminal stenosis
- Sacroiliac joint pain
- Myofascial pain (including piriformis-related patterns)
Step 3: Focused General History (Targeted, Not Exhaustive)
Use history to localize the likely source and decide what to test on examination.
Key History Domains
- Pain profile: onset, duration, progression, severity
- Pattern: axial vs leg-dominant pain; unilateral vs bilateral; dermatomal vs non-dermatomal
- Aggravating/relieving factors: posture, walking tolerance, sitting, bending, coughing/sneezing
- Functional limitations: standing time, walking distance, sleep disturbance
- Neurological symptoms: numbness, tingling, weakness, gait issues
- Systemic clues: fever, weight loss, night pain, immunosuppression, cancer history
- Trauma / osteoporosis risk: falls, elderly, steroid exposure
- Prior treatments and response: medications, physiotherapy, injections, surgery
Step 4: Physical Examination Workflow
A consistent sequence improves accuracy and reduces missed findings.
A. Inspection
Look for:
- Postural asymmetry, scoliosis, pelvic tilt
- Antalgic posture
- Guarding and movement avoidance
- Gait abnormalities
B. Palpation
Assess:
- Midline tenderness (consider bony pathology)
- Paraspinal muscle spasm / trigger points
- Localized tenderness over SI region, facets, gluteal region
C. Range of Motion (ROM)
Evaluate:
- Flexion, extension, lateral bending, rotation
- Pain provocation patterns (e.g., extension intolerance may suggest facet/stenosis patterns)
Step 5: Neurological Examination (Non-Negotiable)
A neurological screen should be standard in back pain assessment when leg symptoms or red flags exist.
Core Components
- Motor testing: key myotomes (hip flexion, knee extension, ankle dorsiflexion, great toe extension, plantarflexion)
- Sensory testing: dermatomal assessment
- Reflexes: knee and ankle reflexes
- Autonomic screening (when indicated): bladder/bowel red flag questions and perineal symptoms
Tip: Document clearly. Even subtle objective deficits may change urgency and imaging decisions.
Step 6: Special Tests (Use a Purpose-Driven Selection)
Special tests are most valuable when chosen based on the suspected condition, rather than performed as a routine “battery.”
Special Tests You Should Know
1) Tests for Lumbar Nerve Root Irritation (Radicular Pattern)
Straight Leg Raise (SLR) / Lasègue Test
- Used when leg pain suggests nerve root irritation.
- A positive test supports radicular involvement, especially when symptoms reproduce in a typical distribution.
Practical note: Always interpret with history + neuro exam; an isolated “positive SLR” without supportive clinical context can mislead.
2) Tests for Spinal Canal Stenosis
Use when symptoms suggest stenosis patterns such as:
- Leg symptoms with walking/standing
- Symptom relief with sitting or flexion posture
- Reduced walking tolerance
Exam strategy: combine posture-based provocation (often extension) with functional history.
3) Tests for Sacroiliac (SI) Joint Pain
SI joint pain is best supported by a cluster of provocation tests rather than one test alone.
SI Joint Provocation Tests
- Distraction test
- Thigh thrust test
- Gaenslen’s test
- Compression test
- FABER test
- Sacral thrust
Clinical approach: If multiple SI provocation tests reproduce the patient’s familiar pain, SI joint involvement becomes more likely and can guide confirmatory pathways and targeted interventions.
4) Tests for Piriformis / Deep Gluteal Myofascial Pain Patterns
Consider when pain is buttock-dominant, worsens with hip movements, sitting intolerance, or presents with pseudo-sciatic distribution without clear neuro deficits.
Piriformis / Deep Gluteal Tests
- Freiberg’s maneuver
- FAIR test (lateral position)
- Beatty test
Interpretation note: These tests help identify a deep gluteal source, but should be correlated with tenderness, movement provocation, and exclusion of true radiculopathy.
A Simple, Clinic-Ready Back Pain Evaluation Checklist
- Red flags present? If yes → urgent pathway
- History pattern suggests: radicular / stenosis / SIJ / myofascial / mechanical
- Perform inspection → palpation → ROM
- Do neurological exam (motor/sensory/reflexes; autonomic if needed)
- Use condition-specific special tests
- Document objective findings + most likely pain generator
- Plan: conservative care vs imaging vs referral vs targeted interventions
Frequently Asked Questions
What are the most important red flags in back pain?
Major trauma, suspected tumor/infection/fracture, objective neurological deficits (motor/sensory/autonomic), and severe disproportionate pain are key red flags that change urgency.
Do I need to do special tests for every back pain patient?
No. Special tests should be selected based on the suspected condition from history and exam, not performed as a routine bundle.
Is one SI joint test enough to diagnose SI joint pain?
Typically no. SI joint pain assessment is stronger when multiple provocation tests reproduce familiar pain.
When should I prioritize a neurological examination?
Any time there is leg pain, numbness/tingling, weakness, gait disturbance, or concern for progressive symptoms—plus whenever red flags are suspected.
Author: Gautam Das
