Lower Back Pain: Prolapsed Disc

Key points

• A prolapsed lumbar disc usually produces clear dermatomal leg pain associated with neurological deficits
• Leg pain is usually worse than back pain, and often worse when sitting
• L3 nerve root compression: sensory loss over the anterior thigh, weak quadriceps, reduced knee reflex, positive femoral stretch test
• L4 nerve root compression: sensory loss over the anterior aspect of the knee, weak quadriceps, reduced knee reflex, positive femoral stretch test
• L5 nerve root compression: sensory loss over the dorsum of the foot, weakness in foot and big toe dorsiflexion, reflexes generally intact
• S1 nerve root compression: sensory loss over the posterolateral leg and lateral foot, weakness in plantar flexion, reduced ankle reflex, positive sciatic nerve stretch test
• Management is similar to other musculoskeletal lower back pain: analgesia, physiotherapy, exercises; refer for MRI if symptoms persist