Degenerative Disc Disease and Sciatica

The term "Degenerative Disc Disease" (DDD) sounds alarming, but it is actually a misnomer. It is not a disease at all, but rather the medical term for the natural, expected wear-and-tear process that happens to spinal discs as we age. While everyone experiences some degree of disc degeneration, for some, this process causes significant lower back pain and can trigger sciatica.

What Happens During Disc Degeneration?

When you are young, your spinal discs are plump, flexible, and filled with fluid—mostly water. This high water content allows them to act as effective shock absorbers between the bony vertebrae of your spine.

As part of the normal aging process, several changes occur:

• Loss of Hydration: The discs gradually lose their water content. They become thinner, flatter, and less capable of absorbing shock.
• Micro-Tears: The tough outer layer of the disc (the annulus) accumulates tiny tears from daily movement and stress.
• Loss of Disc Height: As the discs flatten out, the distance between the vertebrae shrinks.

How DDD Causes Sciatica

Degenerative disc disease creates a chain reaction in the spine that can ultimately compress the sciatic nerve. This happens in a few ways:

1. Foraminal Narrowing: The sciatic nerve roots exit the spine through small bony openings called foramina. When a disc loses its height and flattens out, the space between the vertebrae collapses. This physically shrinks the size of the foramina, pinching the exiting nerve root.
2. Increased Risk of Herniation: Because degenerated discs are weaker and have micro-tears in their outer walls, they are much more susceptible to bulging or fully herniating, which directly compresses the nerve.
3. Bone Spurs: The loss of disc cushioning causes the vertebrae to rub together. The body attempts to stabilize this abnormal movement by growing new bone (bone spurs), which can intrude into the spinal canal and compress nerves.

Symptoms of Sciatica Caused by DDD

In addition to the standard radiating leg pain of sciatica, patients with underlying DDD often experience:

• A low-grade, continuous ache in the lower back that occasionally flares up into severe pain.
• Pain that worsens when sitting, bending, or lifting, and improves slightly when walking or changing positions frequently.
• Stiffness in the lower back, especially in the morning upon waking.