Lumbar Disc Herniation
The intervertebral disc is the shock absorbing cushion located between each vertebral body. Discs consist of an outer fibrous ring called the annulus fibrosis, with an inner gel-like substance called the nucleus pulposus. Disc herniation occurs when the outer annulus fibres begin to crack and break open allowing the inner nucleus pulposus to begin to leak out. There are four stages of disc herniation:
- Disc degeneration: weakening of the disc.
- Prolapse or bulging disc herniation: a change in position or shape of the disc (disc bulge) causing some impingement into the spinal canal.
- Extrusion: when the inner nucleus pulposus breaks through the outer annulus fibrosis but remains within the disc.
- Sequestration: when the inner nucleus pulposus breaks through the outer annulus fibrosis and lies outside the disc within the spinal canal.
Disc herniation most commonly affects the lumbar or lower back region. Symptoms of lumbar disc herniation include back pain, leg and/or foot pain, muscle weakness, numbness or tingling, and loss of bowel or bladder control. Risk factors for the development of lumbar disc herniation include age, improper lifting techniques, obesity, repetitive trauma to the spine, prolonged sitting posture (desk work or driving), sedentary lifestyle and smoking.