What is the assessment and diagnosis for a patient presenting with right lower back pain radiating to the right leg and a history of sciatica?

Assessment and Diagnosis for Right Lower Back Pain Radiating to Right Leg with History of Sciatica

This patient most likely has lumbar radiculopathy due to disc herniation at L4/L5 or L5/S1, and your assessment should focus on confirming the specific nerve root involved through targeted neurological examination and straight-leg raise testing. 1

Clinical Assessment Approach

History Taking

Your focused history should determine:

• Pain distribution pattern: Confirm the pain follows a typical lumbar nerve root distribution down the leg below the knee into the foot and toes 2, 3
• Duration and severity: Document if symptoms are acute (< 4 weeks), subacute (4-12 weeks), or chronic (> 12 weeks) 1
• Red flag symptoms to rule out serious pathology 1:
  • Urinary retention or fecal incontinence (cauda equina syndrome - 90% sensitive for urinary retention) 1
  • Progressive motor weakness at multiple levels
  • History of cancer, unexplained weight loss, age > 50 years, or failure to improve after 1 month (cancer risk factors) 1
  • Fever, IV drug use, or recent infection (vertebral infection) 1
  • History of osteoporosis or steroid use (compression fracture risk) 1

Physical Examination

Perform a focused neurological examination targeting specific nerve roots 1:

• L4 nerve root: Test knee extension strength and patellar reflexes
• L5 nerve root: Test great toe and foot dorsiflexion strength (most commonly affected with L4/L5 herniation) 1
• S1 nerve root: Test foot plantarflexion and ankle reflexes (most commonly affected with L5/S1 herniation) 1
• Sensory distribution: Map the dermatomal pattern of sensory symptoms 1

Straight-leg raise testing 1:

• Positive test = reproduction of sciatic pain between 30-70 degrees of leg elevation
• Sensitivity: 91% but specificity only 26% for herniated disc 1
• Crossed straight-leg raise (raising the unaffected leg reproduces pain in the affected leg): More specific (88%) but less sensitive (29%) 1

Psychosocial assessment is critical as these factors predict outcomes more strongly than physical findings 1:

• Depression, passive coping strategies, job dissatisfaction, higher disability levels, disputed compensation claims, or somatization 1

Diagnosis

Your working diagnosis should be: Lumbar radiculopathy (sciatica) secondary to probable disc herniation at L4/L5 or L5/S1 1, 2

More than 90% of symptomatic lumbar disc herniations causing radiculopathy occur at these two levels 1. The typical history of back and leg pain in a lumbar nerve root distribution has fairly high sensitivity for herniated disc, though specificity is uncertain 1.

Diagnostic Classification

Place this patient in the category of "back pain potentially associated with radiculopathy" rather than nonspecific low back pain 1. This classification guides subsequent management decisions.

Imaging Decisions

Do NOT order routine imaging initially 1. The natural history of lumbar disc herniation with radiculopathy shows improvement within the first 4 weeks with noninvasive management in most patients 1.

Order MRI (preferred) or CT only if 1:

• Symptoms persist beyond 6-8 weeks of conservative treatment AND
• The patient is a potential candidate for surgery or epidural steroid injection 1
• OR if red flags suggest serious underlying pathology (cancer, infection, cauda equina syndrome) 1

MRI is preferred over CT because it visualizes soft tissues better and avoids ionizing radiation 1.

Common Pitfalls

• Don't assume the level of disc herniation matches the radicular symptoms: Rare cases exist where L2/3 herniation causes L5 radiculopathy 4
• Don't confuse radicular pain with referred pain: True radiculopathy extends below the knee into the foot, while referred pain from the lower back typically doesn't 3
• Don't order imaging in the first 6-8 weeks unless red flags are present - it doesn't improve outcomes and leads to unnecessary interventions 1
• Don't overlook psychosocial factors: They are stronger predictors of chronic disability than physical findings 1

Follow-up Timing

Reevaluate patients with persistent, unimproved symptoms after 1 month, as most acute low back pain improves substantially within this timeframe 1. However, given this patient has radiculopathy, earlier or more frequent reevaluation may be appropriate if symptoms are severe 1.