Discogenic Back Pain - A Detailed Review

Introduction

Back pain is a common ailment affecting millions worldwide, significantly impacting their quality of life. It is estimated that most individuals, around 80 percent of all populations, will experience low back pain at some point.

What Is Discogenic Back Pain?

Discogenic back pain, as the name suggests, originates in the intervertebral discs. Discogenic back pain is a type of pain that emerges as a result of various factors connected to the later stages of intervertebral disc (IVD) degeneration. The pain can be caused by issues like instability in the spine, damage to the endplates of the vertebrae, the growth of nerves into the affected area, heightened sensitivity of nerves, and inflammation.

Discogenic pain commonly affects the lower back region of the lumbar spine. The lumbar spine comprises the five vertebrae in the spinal column's lower part, typically labeled L1 to L5. These intervertebral discs are more susceptible to degeneration and damage, leading to lumbar discogenic pain.

In people with discogenic low back pain, the production of certain substances called proinflammatory mediators or cytokines often increases. These substances are typically made in the inner part of the disc (nucleus pulposus) and are considered a significant factor in causing discogenic low back pain.

What Causes Discogenic Back Pain?

The intervertebral disc between vertebrae consists of three key components: the central gel-like nucleus pulposus, the outer annulus fibrosus, and the upper and lower cartilage endplates. These components are essential for disc function. Discogenic pain is a type of lower back pain that happens when the intervertebral discs are harmed either chemically or mechanically. This damage can occur due to injuries or simply as the discs age.

Common causes of discogenic back pain include:

Intervertebral Disc Degeneration (IVD): Degeneration of the intervertebral disc is a primary factor contributing to discogenic low back pain. Disc degeneration can occur due to various factors, including genetic predisposition, mechanical load, and nutritional influences. Discs are typically poorly innervated, but in degenerated discs, nerve fibers increase, including nociceptive and sympathetic fibers, potentially contributing to low back pain.

Other factors contributing to IVD include:

• Morphological changes like disc prolapse, herniation, spondylosis, spondylolisthesis, Modic changes, and Schmorl nodes.

• High mechanical stress on the spine.

• Damage from oxidative stress.

• Systemic metabolic disorders like diabetes and obesity.

• Genetic variations can influence susceptibility to discogenic pain.

• Alterations in the central nervous system.

Who Gets Discogenic Low Back Pain?

Discogenic low back pain can happen to lots of different people, but it is usually seen more often in certain groups.

Here are some factors that can affect who gets discogenic low back pain:

• Older adults.

• People with jobs that place excessive mechanical stress on the spine.

• Individuals are genetically predisposed to disc degeneration.

• People encounter traumatic events like accidents or sports injuries.

• Obese individuals.

• People with less physical activity and poor posture.

• Persons who smoke.

What Does Discogenic Back Pain Feel Like?

Discogenic back pain can vary from person to person, but it is usually described as a deep, aching discomfort in the lower back. The pain is often localized and may not radiate down the leg, as with some other types of back pain.

People with discogenic back pain might feel:

• Dull, constant aching pain can be described as a persistent, non-sharp ache in the lower back.

• Activities that stress the intervertebral discs, such as bending or sitting for extended periods, can worsen the pain.

• Resting or changing positions may reduce some discomfort associated with discogenic back pain.

• The lower back may feel stiff, making it difficult to move comfortably.

How Is Discogenic Back Pain Diagnosed?

Diagnosing discogenic back pain involves understanding the role of intervertebral discs in causing pain. The various tools used for diagnosis of the condition include:

• Clinical Examination: A thorough examination and patient history are essential to diagnose back pain. Red flags indicating possible serious conditions must be considered and ruled out. Nonorganic signs, such as signs of psychological distress, should be noted.

• Pain Diagrams or Questionnaires: Patients may be asked to fill out pain diagrams or questionnaires to help pinpoint the location and characteristics of their pain.

• Serum Biomarkers: Emerging as a diagnostic tool for back pain, serum biomarkers offer objective measurements. These markers can indicate the biological processes involved in discogenic pain or the presence of systemic disorders like osteoporosis. Candidates include various cytokines and proteins like C-reactive proteins and collagen types.

• Discogram Evaluation: Discography is a procedure that involves injecting a contrast medium into the disc and is used to characterize disc pathology.

• MRI: Magnetic resonance imaging (MRI) is widely used for diagnosing disc degeneration. Specific MRI findings, like high-intensity zones (HIZ) and type 1 modic changes, can indicate disc-related pain.

How Is Discogenic Back Pain Treated?

Conservative Management:

• Non-operative management includes various approaches, such as oral analgesics (pain medications), physiotherapy, psychotherapy, and acupuncture or dry needling.

• Oral pharmaceutical management may involve medications like Acetaminophen, NSAIDs (non-steroidal anti-inflammatory drugs), muscle relaxants, Tramadol, steroids, and opioids. However, long-term opioid use is discouraged due to potential dependence.

Invasive Treatments:

• Fusion surgeries aim to remove the painful disc and stabilize the spine to prevent further pain. However, these surgeries are invasive and can lead to complications and adjacent segment disorders.

• Total disc replacement is a surgical option with a lower risk of complications compared to fusion. It is more suitable for spinal levels where maintaining mobility is crucial.

• Minimally invasive tubular decompressive surgeries can be effective for specific cases with localized lesions and disc herniation.

Minimally Invasive Treatments:

• Thermal intradiscal techniques use radiofrequency probes to treat painful lesions within the disc. These methods aim to eliminate inflammatory tissue and nerve fibers, but their outcomes have been relatively poor.

• Electrostimulation, such as spinal cord stimulation, can be used for chronic neuropathic pain. However, it comes with a relatively high rate of adverse events.

• Epidural injection therapy with steroids and anesthetics is widely used for lumbar radiculopathy and low back pain.

Regenerative Medicine:

Regenerative therapies show promise in early-stage disc degeneration, including mesenchymal stem cell (MSC) therapy, platelet-rich plasma (PRP), and chondrocyte transplantation. These treatments have demonstrated some positive results, but larger-scale trials are needed to confirm their safety and efficacy.

Newer Repair Techniques:

• Researchers have created materials and devices to seal the outer part of spinal discs (annulus) and replace the inner part (nucleus pulposus) after surgery to prevent the disc from herniating again. Some of these devices are used in patients, but more research is needed to ensure they work well.

• Another approach is to grow new spinal disc tissue in the lab (whole IVD tissue engineering) and use it to replace damaged discs.

Conclusion

Discogenic back pain is a debilitating condition that affects many individuals. Effective management involves understanding the condition, seeking appropriate diagnosis and treatment, and adopting self-care measures. Regular exercise, maintaining a healthy weight, practicing good posture, using lumbar support, and staying hydrated are essential steps that can be done to reduce symptoms and prevent recurrence.