Lumbar Radiculopathy: Causes, Diagnosis, and Treatment

Introduction

Lumbar radiculopathy, commonly referred to as radicular nerve pain or sciatica, results from irritation or compression of spinal nerve roots in the lumbar spine. This condition can cause pain, numbness, and weakness radiating along the affected nerve distribution. It is a frequent cause of lower back and leg pain and can significantly impact a patient’s quality of life.

Commonly Affected Levels and Pain Distribution

Lumbar radiculopathy most frequently affects the following nerve roots:

• L4 Nerve Root (L3-L4 Disc Herniation): Pain radiates from the lower back to the anterior thigh and medial knee. Patients may experience quadriceps weakness and diminished patellar reflex.

• L5 Nerve Root (L4-L5 Disc Herniation): Pain extends from the lower back to the lateral thigh, anterior shin, and dorsum of the foot, often affecting the great toe. Weakness in foot dorsiflexion and toe extension may be noted.

• S1 Nerve Root (L5-S1 Disc Herniation): Pain follows the posterior thigh, calf, and lateral foot. Weakness in ankle plantarflexion (difficulty standing on tiptoes) and diminished Achilles reflex are common findings.

Differential Diagnoses

Several conditions can mimic lumbar radiculopathy and should be considered:

• Spinal Stenosis: Often presents with bilateral leg pain and neurogenic claudication rather than unilateral radicular symptoms.

• Peripheral Neuropathy: Diffuse rather than dermatomal distribution of symptoms.

• Piriformis Syndrome: Sciatic nerve compression at the piriformis muscle, leading to gluteal and leg pain.

• Hip Pathology (e.g., osteoarthritis, labral tears): Can cause referred pain to the thigh and mimic radicular symptoms.

• Sacroiliac Joint Dysfunction: Pain localized to the sacroiliac joint and posterior thigh, often without neurological deficits.

Treatment Options

Management of lumbar radiculopathy follows a stepwise approach, ranging from conservative care to surgical intervention when necessary.

1. Conservative Treatment

• Activity Modification: Avoiding activities that exacerbate symptoms while maintaining mobility.

• Medications:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and inflammation.

  • Neuropathic agents (gabapentinoids, tricyclic antidepressants) for nerve pain modulation.

  • Short courses of oral corticosteroids in acute exacerbations.

• Physical Therapy:

  • Strengthening exercises for core and paraspinal muscles.

  • Stretching techniques to alleviate nerve tension.

  • Manual therapy and ergonomic education.

2. Minimally Invasive Interventions

• Epidural Steroid Injections (ESIs):

  • Corticosteroid injections near the affected nerve root to reduce inflammation and provide temporary pain relief.

  • Particularly beneficial for acute radicular pain unresponsive to conservative measures.

• Selective Nerve Root Blocks:

  • Targeted injection of local anaesthetic and corticosteroids around a specific nerve root for diagnostic and therapeutic purposes.

3. Surgical Intervention

Surgery is considered when conservative and minimally invasive treatments fail, particularly in cases of significant neurological deficits or severe, persistent pain.

Indications for Surgery:

• Progressive or severe motor weakness (e.g., foot drop due to L5 nerve root compression).

• Intractable pain despite 6-12 weeks of conservative treatment.

• Cauda equina syndrome (surgical emergency) presenting with:

  • Bowel and/or bladder dysfunction.

  • Saddle anaesthesia.

  • Bilateral lower limb weakness.

Surgical Options:

• Microdiscectomy:

  • Removal of herniated disc material compressing the nerve root.

  • Preferred for single-level disc herniations causing severe radicular pain.

• Laminectomy:

  • Decompression of the spinal canal in cases of stenosis with nerve root compression.

• Spinal Fusion:

  • Indicated for instability due to spondylolisthesis or recurrent disc herniation.

Conclusion

Lumbar radiculopathy is a common yet potentially debilitating condition resulting from nerve root compression in the lumbar spine. A thorough understanding of pain distribution, differential diagnoses, and treatment modalities is essential for optimal management. Conservative treatments are effective in most cases, but minimally invasive procedures and surgical intervention may be required for persistent or severe symptoms.

References

1. Deyo RA, et al. (2014). "Managing Low Back Pain and Sciatica: Evidence-Based Approaches." New England Journal of Medicine, 371(16), 1552-1563.

2. Ropper AH, et al. (2015). "Lumbar Radiculopathy and Sciatica." New England Journal of Medicine, 372(14), 1240-1248.

3. Kreiner DS, et al. (2020). "Guidelines for the Management of Lumbar Disc Herniation with Radiculopathy." Spine Journal, 20(1), 135-148.

4. Gibson JN, et al. (2007). "Surgical Versus Non-Surgical Treatment for Lumbar Disc Herniation: A Meta-Analysis." Spine (Phila Pa 1976), 32(4), 816-823.