Spinal Disc Herniation

Spinal disc herniation, also known as slipped disc, bulging disc, ruptured disc, herniated disc, prolapsed disc, or herniated nucleus pulposus, is an injury to the intervertebral disc between two spinal vertebrae. This condition is typically caused by excessive strain or trauma to the spine and can lead to back pain, sensory changes, and physical disability.

Signs and Symptoms

Symptoms of a herniated disc can vary based on the location and severity of the herniation. They might include:

• Localised or radiating pain: Continuous pain in the neck, back, or areas served by affected nerves.
• Sensory changes: Numbness, tingling, or paresthesia.
• Motor disturbances: Muscular weakness, paralysis, and changes in reflexes.
• Sciatica: If the lumbar region is affected, symptoms may include pain radiating down the leg due to sciatic nerve involvement.

In severe cases, particularly with large herniations, both sides of the body may be affected, potentially leading to cauda equina syndrome, characterised by loss of bowel and bladder control and sexual dysfunction.

Causes

Disc herniation often results from a combination of trauma, excessive strain, and age-related degeneration. Specific factors include:

• Increased internal pressure: Activities like lifting or bending can increase disc pressure, causing the nucleus pulposus to press against the annulus fibrosus, leading to rupture.
• Degenerative changes: Ageing and degenerative disc disease result in the nucleus becoming fibrous and stiff, increasing stress on the annulus and leading to fissures.
• Genetic mutations: Mutations in genes related to the extracellular matrix can contribute to lumbar disc herniation.
• Occupational and athletic activities: Repetitive strain or sudden impacts, especially in contact sports, can also cause disc herniations.

Pathophysiology

Most spinal disc herniations occur in the lumbar (95%) and cervical regions, with the thoracic region being less commonly affected. Herniations typically occur postero-laterally due to the thinner annulus fibrosus and lack of reinforcement by ligaments. In the cervical spine, a herniation impinging on the nerve exiting between two vertebrae can cause symptoms in the corresponding areas served by that nerve.

Diagnosis

Physical Examination

A diagnosis is made based on patient history, symptoms, and physical exams, often including tests to rule out other conditions with similar symptoms.

Imaging

• X-rays: Useful for excluding other conditions but limited in soft tissue imaging.
• CT Scan: Effective for viewing bony structures but less so for nerve roots.
• MRI: The gold standard for diagnosing disc herniation, offering detailed images of soft tissues, including the discs and nerves.

Treatment

Non-Surgical

Most cases are treated conservatively, focusing on:

• Medication: NSAIDs for pain relief.
• Physical Therapy: Exercises to strengthen the core and improve posture.
• Lifestyle Modifications: Weight control and education on proper body mechanics.

Surgery

Surgery is considered when conservative treatments fail or in cases of severe symptoms such as significant leg weakness, bladder issues, or cauda equina syndrome. Surgical options include discectomy, microdiscectomy, and endoscopic procedures.

Epidemiology

Lumbar disc herniation is the most common form, occurring 15 times more often than cervical disc herniation. It is a prevalent cause of low back pain and sciatica, particularly in individuals in their thirties and forties. The risk decreases with age as the nucleus pulposus dehydrates.

Prevention

Prevention strategies include education on proper lifting techniques, maintaining good posture, and engaging in exercises to strengthen the back. Weight management and avoiding excessive strain are also very important.

Future treatments may include innovative approaches like stem cell therapy to address disc degeneration and promote regeneration.

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Self-assessment MCQs (single best answer)

What is another term for spinal disc herniation?

Which region of the spine is most commonly affected by disc herniation?

Which imaging technique is considered the gold standard for diagnosing disc herniation?

What is a common symptom of lumbar disc herniation that involves pain radiating down the leg?

What is the primary cause of spinal disc herniation?

Which type of treatment is generally considered first for managing disc herniation?

Which of the following is NOT a typical symptom of a herniated disc?

What condition can result from a severe herniated disc pressing on the lower spinal cord, causing loss of bowel and bladder control?

Which lifestyle modification can help prevent spinal disc herniation?

What typically happens to the nucleus pulposus of the disc as a person ages?