What is the Difference Between a Disc Herniation and a Disc Extrusion?

disc herniation vs disc extrusion

What is the Difference Between a Disc Herniation and a Disc Extrusion?

Spine Anatomy

The discs provide shock absorption between the vertebral bones and allow for the motion of the spine. The spine is a repeating sequence of vertebral bones, separated by discs in the front of the spine and a pair of facet joints in the back of the spine. Because the discs are located in the front of the spine, disc pain classically worsens while sitting and improves while standing. Disc pain can be felt in the low back or can refer pain into the buttock region and even into the back of the thighs. This referred disc pain can be felt on one side or both. The typical evolution of disc pain over time is that the flare-up episodes begin to occur more frequently, last longer, and the associated pain becomes more intense than previously. Over time the situation can progress to constant daily lumbar (low back) disc pain with superimposed flare-ups. This process erodes quality of life by interfering with activities and function. The result is frustration, which can lead to desperation.

How Disc Abnormalities Occur

The center of the disc is called the nucleus pulposus and has a gel-like consistency. The disc’s outer ring, called the annulus fibrosus, has a sturdier but still flexible structure. Due to injury or degeneration, cracks (fissures) start to develop in the discs from the inside out. These cracks are called fissures and often correlate on an MRI with a high-intensity zone (HIZ) visible in the disc annulus. Sometimes MRI reports call these disc abnormalities “annular fissures” or “annular rents”. Because the disc lacks an adequate blood supply, these disc annulus fissures cannot heal spontaneously. As a result, disc annulus fissures extend in length and become more numerous with additional branching complexity over time. The discs themselves can become painful because of this process.

Disc Herniation vs. Disc Extrusion

If a disc fissure is large enough, the nucleus pulposus material in the center of the disc can escape outside the disc. The distinction between a herniation and an extrusion depends on the shape of the nucleus pulposus material that has escaped. If the width of the material at its tip is narrower than at its base, then it is referred to as a herniation. If the width of the material at its tip is wider than at its base, then it is referred to as an extrusion. Therefore, having a disc herniation may not feel different than having a disc extrusion. An effort is being made for all Radiologists (doctors who specialize in interpreting MRIs, x-rays, etc.) to use standardized vocabulary in their MRI reports, especially when it comes to spine MRIs. The difference between a herniation and an extrusion allows the Radiologist to communicate the appearance of the disc abnormality. Although these terms are sometimes used interchangeably, they have different meanings regarding how discs appear on an MRI, even though they may not feel different to a person with disc abnormality. An effort is being made to avoid terms like “slipped disc” and “ruptured disc.”

When nucleus pulposus material has escaped from the center of the disc, it ends up in a location where only spinal nerves should be. The result is inflammation of nerve tissue but also compression on the nerves caused by the displaced disc material. The disc fissures that allow herniations and extrusions to occur will never repair on their own because the disc lacks a blood supply sufficient for healing. Disc fissures cannot be surgically sewn for the same lack of blood supply. If left untreated, the center of the disc (nucleus pulposus) decreases in volume, causing the disc to decrease in height and eventually collapse. This process is called Degenerative Disc Disease. On MRI, these discs appear dark and flat compared to normal discs.

Learn About Discseel® for Disc Herniation and Disc Extrusions

The only way to solve this problem is to seal the disc fissures, ideally before the disc collapses. Because this cannot be accomplished surgically, an ideal non-surgical alternative is Discseel®. This new non-surgical procedure injects the healing protein fibrin into each tear to immediately seal the disc. Over the following months, the fibrin promotes disc tissue growth, sealing and healing previously torn discs. Several other injection procedures attempt to treat disc pain (stem cells, PRP, etc.), but they are all limited because they cannot immediately seal the disc tears, and these products end up leaking back out of the disc, which minimizes their benefit. Learn more about Discseel® at RegenerativeSpineAndJoint.com and discover how your low back disc herniations and disc extrusions can be successfully treated non-surgically.

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I’m Boris Terebuh MD, Ohio’s first and most experienced Discseel® provider. I am also the Founder & Medical Director of the Regenerative Spine & Joint Center