Slipped Disc (Disc Herniation)

Disc herniation, commonly referred to as a slipped disc, is a prevalent condition that affects many individuals, causing significant discomfort and disability. This article delves into the intricate details of disc herniation, exploring its pathophysiology, clinical presentation, diagnostic techniques, surgical interventions, and the crucial role of the orthopaedic spine surgeon in managing this condition.

Key Takeaways

• Disc herniation occurs when the intervertebral disc’s inner gel-like core protrudes through its outer ring, often due to wear and tear or sudden strain, leading to nerve compression and pain.
• Accurate diagnosis of disc herniation involves a combination of history taking, physical examination and advanced imaging techniques such as MRI scans to differentiate it from other conditions with similar symptoms.
• Surgical intervention may be necessary for severe cases of disc herniation where there is neurological impact, followed by comprehensive postoperative care and rehabilitation to ensure optimal recovery.

Pathophysiology of Disc Herniation

Biomechanics of the Intervertebral Disc

The intervertebral disc is a flat, circular structure situated between each spinal bone. It consists of a central gel-like matrix known as the nucleus pulposus, encapsulated by outer layers of fibrous tissues called the annulus fibrosus. This structure serves to cushion impact and distribute load across the joint. Over time, intervertebral discs lose water, reducing their functional capacity to resist axial loading. This desiccation process leads to a decrease in the water content of the nucleus pulposus and weakening of the annulus fibrosus, which may result in the disc bulging or herniating into the spinal canal.

Mechanisms Leading to Herniation

A herniated disc, also known as a slipped or prolapsed disc, occurs when the gelatinous nucleus pulposus squeezes through the annulus fibrosus and bulges into the spinal canal. This can happen due to injury or weakness in the disc structure. The herniation may cause nerve irritation or compression, leading to pain, numbness, or weakness in the back and legs. Direct compression of the spinal nerve root or chemical irritation from chemical irritants leaking from the disc material are common mechanisms by which herniated discs affect nerve roots.

Impact on Neural Structures

When a disc herniates, it can compress or irritate the spinal nerve roots, leading to symptoms such as back pain, sciatica (pain radiating down the leg), numbness of the legs, and weakness of the feet or ankle movements.

Clinical Presentation and Diagnosis

Common Symptoms of Disc Herniation

Patients with disc herniation often present with a variety of symptoms depending on the location and severity of the herniation. Pain is a predominant symptom and can be localized to the lumbar or cervical spine. In cases where the herniation occurs in the cervical spine, the pain may extend to the shoulder and arm, often described as sharp or burning. Additionally, patients may experience numbness, tingling, and weakness in the neck, shoulders, arms, and hands. These symptoms are indicative of nerve root compression, which is more likely to occur with a herniated disc compared to a bulging disc.

Diagnostic Imaging Techniques

Accurate diagnosis of disc herniation relies heavily on imaging techniques. Magnetic Resonance Imaging (MRI) is the gold standard for visualizing soft tissue structures, including the intervertebral discs and neural elements. MRI provides detailed images that can reveal the extent of disc herniation and its impact on adjacent neural structures. In some cases, discography may be performed to confirm if a specific disc is causing pain by injecting saline with contrast into the disc and observing the response. This is called a discogram.

Differential Diagnosis

The differential diagnosis for disc herniation includes a range of conditions that can mimic its symptoms. It is crucial to differentiate between discogenic pain and other potential causes such as spinal stenosis, spondylolisthesis, and peripheral neuropathy. A thorough clinical evaluation, combined with imaging studies, helps in ruling out these conditions.

Surgical Interventions for Herniated Discs

Surgical interventions for herniated discs are considered when conservative treatments fail to alleviate symptoms. Surgery is often reserved for severe cases where pain and neurological deficits significantly impair daily activities. Various surgical techniques are employed to remove or repair the herniated disc material, aiming to relieve pressure on the affected nerve roots and spinal cord.

The surgery can be done via various approaches:

1. Mini open approach (McCulloch retractors)
2. Tubular approach
3. Endoscopic approach (biportal or uniportal)

All of these approaches involve minimal tissue dissection and most patient go home the next day after surgery.

Post Op Care after a discectomy

The first 2 weeks after surgery, the wound will be healing so avoid bending the back or lifting heavy loads. Walking and sitting is as per normal but maintain a straight spine and avoid slouching.

After the wounds are healed at 2 weeks, a referral to a physiotherapist is recommended to being gentle mobilisation and core strengthening so that good posture is maintained to reduce the risk of a recurrent disc prolapse and to maintain the health of the remaining discs.