Acute lumbar disc prolapse

Pathogenesis:

• The central nucleus pulposus may extrude into a fissure in the surrounding annulus fibrosis and cause acute pain and muscle spasm
• These events are usually self-limiting
• A disc prolapse occurs when the extrusion extends beyond the limits of the fibrous annulus fibrosis
• The weakest part of the annulus is posterolaterally – where the disc may impinge on emerging spinal nerve roots in the root canal

Clinical features:

• The episode starts dramatically during lifting, twisting or bending
• Produces a typical combination of:
• Lower back pain
• Muscle spasm
• Severe lancinating pains, paraesthesia, numbness and neurological signs in one leg (rarely both)

• The back pain is:
• Diffuse
• Usually unilateral
• Radiates into the buttock

• The muscle spasm leads to a scoliosis, which reduces when lying down

Treatment:

• Advise bedrest:
• Lying flat for a lower disc
• Semi-reclining for a high lumbar disc
• Analgesia
• Muscle relaxants
• Physiotherapy
• If the neurological signs are severe and the pain persists and is severe for >6-10 weeks:
• Microdiscectomy
• Hemilaminectomy