Why Do Herniated Discs Cause Pain in Some People but Not Others?
A herniated disc sounds like something that should always hurt. After all, when the soft cushioning between your vertebrae ruptures and the inner material pushes out, it seems logical that pain would follow. Yet medical imaging studies have revealed a puzzling truth: many people walk around with herniated discs and feel absolutely nothing. In this article, we dive deeper into the fascinating reasons why some individuals with documented disc herniations experience debilitating pain while others remain completely free of symptoms and what this means for how we understand and treat back pain.
The Surprising Prevalence of Silent Herniations
Herniated discs are far more common than most people realize, and many exist without causing any symptoms whatsoever. Multiple studies using MRI scans on people without back pain have found that approximately 30 to 40 percent of adults have at least one herniated disc, with this number increasing significantly with age. By age 60, more than half of asymptomatic individuals show evidence of disc herniations on imaging.
This discovery has fundamentally challenged the traditional assumption that finding a herniated disc, also known as a slipped disc or ruptured disc, on an MRI automatically explains a patient’s pain. The presence of a herniation does not necessarily mean it is the source of discomfort, and conversely, the absence of visible damage does not mean pain is not real or significant.
The Role of Nerve Compression
The key difference between painful and painless herniations often comes down to whether the protruding disc material compresses or irritates a nerve root. When a herniated disc pushes into the spinal canal or through the space where nerve roots exit the spine, it can create pressure on these delicate neural structures. This compression can trigger inflammation, sending pain signals down the affected nerve pathway—a condition known as radiculopathy, or more commonly, sciatica when it affects the sciatic nerve in the lower back.
However, not all herniations involve nerve compression. Some discs herniate in directions that do not impinge on neural tissue. A disc might bulge posteriorly into the spinal canal without actually touching the spinal cord or nerve roots, especially if the spinal canal is spacious enough to accommodate the protrusion. Others may herniate laterally or anteriorly, away from vulnerable nerve structures entirely.
Individual Anatomical Differences
Each person’s spinal anatomy is unique, and these variations play a crucial role in determining whether a herniation causes pain. The size of the spinal canal varies considerably among individuals. People born with naturally wider spinal canals have more room to accommodate disc material without nerve compression, making them less likely to experience symptoms even when herniations occur.
The position and trajectory of nerve roots also differ from person to person. Some individuals have nerve roots that exit the spine at angles that make them less vulnerable to compression from a herniated disc. Additionally, the size and direction of the herniation itself matter tremendously. A small contained herniation that does not breach the outer layers of the disc may cause no symptoms, while a large extrusion that migrates up or down the spine can create significant problems.
The Inflammation Factor
Pain from herniated discs is not solely about mechanical compression. Inflammation plays an equally important role. When disc material herniates, the body’s immune system recognizes it as foreign material and launches an inflammatory response. This inflammation can irritate nearby nerve roots even without direct physical compression, causing pain, numbness, and weakness.
Some people appear to have different inflammatory responses to herniated discs. Genetic factors, overall health status, and immune system variations may explain why one person develops severe inflammatory reactions while another experiences minimal inflammation from a similar herniation. Over time, the body may also reabsorb some herniated disc material, particularly larger extrusions, which can lead to natural pain resolution even without intervention.
The Mind-Body Connection
The experience of pain is never purely physical. Psychological and neurological factors significantly influence how the brain interprets and processes pain signals. Two people with identical herniations might report vastly different pain levels based on factors like stress, anxiety, previous pain experiences, and pain processing sensitivity.
Central sensitization, where the nervous system becomes amplified and reactive, can make some individuals more prone to experiencing pain from relatively minor tissue damage. Conversely, others may have higher pain thresholds or different neural wiring that makes them less sensitive to potentially painful stimuli. Fear and catastrophic thinking about back pain can also amplify pain perception, while positive expectations and active coping strategies can reduce it.
The Stability and Compensation Factor
The spine functions as an integrated system where muscles, ligaments, and other structures work together to maintain stability and distribute forces. People with strong core musculature and good movement patterns may compensate effectively for a herniated disc, preventing it from causing symptoms. Their bodies essentially work around the problem, stabilizing the affected segment and preventing excessive motion that might aggravate nerve structures.
Additionally, some herniations may occur in segments of the spine that are naturally less mobile or less load-bearing, reducing their likelihood of producing symptoms during daily activities. The body’s remarkable ability to adapt and compensate for structural issues often goes unrecognized but plays a vital role in determining whether anatomical findings translate into clinical symptoms.
What This Means for Treatment
Understanding that herniated discs can exist without pain has profound implications for treatment approaches. It suggests that aggressive interventions based solely on imaging findings may not always be necessary or beneficial. Many people with herniated discs that do cause pain experience relief with conservative treatment, including physical therapy, anti-inflammatory medications, and time for natural healing to occur.
This knowledge also reinforces the importance of treating the person, not just the image. Clinical symptoms, functional limitations, and quality of life should guide treatment decisions more than imaging findings alone. A herniated disc seen on MRI does not automatically require surgery, especially when we know that similar findings exist in countless people who feel perfectly fine.
If you have a herniated disc that is not responding to conservative treatment, a discectomy or less invasive microdiscectomy may be discussed and potentially recommended. Although this is generally a very successful procedure, having a large hole in the outer ring of the disc more than doubles the risk of needing another operation. A new treatment, Barricaid, is a bone-anchored device designed to close this hole, and 95 percent of Barricaid patients did not undergo a reoperation due to reherniation in a 2-year study timeframe. This treatment is done immediately following the discectomy—during the same operation—and does not require any additional incisions or time in the hospital.
If you have any questions about the Barricaid treatment, ask your doctor or contact us today.
For full benefit/risk information, please visit: https://www.barricaid.com/instructions.
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