Anatomy, Causes, and Treatments of Vertebral Disc Herniation — Part 1

By Alexander Germanis

The body is a paradox of strength and fragility. Muscles and tendons, working in tandem with bone can carry several times the lifter’s weight; and yet the right amount of pressure or the wrong twist or strain can damage, tear or break those same anatomical elements as if they were nothing. Like an egg—when placed on end, the shell’s shape is considered one of the most architecturally strong in nature, able to support a significant amount of weight. But if the egg rolls off center, the structural integrity is compromised and a catastrophic collapse results.

Along the center of the back, the spinal column supports the entire skeletal structure, provides the pedestal for the command center that is the head and both houses and supports the central nervous system. Aligned between each vertebra or bone of the spine sits a mostly fluid cushion called an intervertebral disc.

This disc is “anatomically like an egg,” explains Dr. Ramsin Benyamin, founder of Millennium Pain Center in Bloomington. “It has a shell, it has a white, and it has a yolk.”

The “yolk,” or nucleus pulposus, is a gelatinous ball comprised mostly of proteoglycans—a type of protein—and collagen. Surrounding this are layers of water-filled fibrous collagen of a stronger type than what resides in the nucleus. These layers comprise the annulus fibrosus or “white.” The exterior layers of fibrous lamellae surround the outer edge of the disc with plates of cartilage capping the ends of the disc that are in direct contact with vertebrae.

Although the disc may visibly resemble a somewhat compressed egg, Dr. Benyamin says, “Functionally it works like a waterbed. It acts like a cushion so the vertebrae are not touching each other; they are separated. It acts like a shock absorber.”

But in order for the waterbed to properly provide cushion, “you need water,” the doctor points out. “The same with a disc. Seventy-five percent of a disc is water. If a disc is damaged, whether by a disc rupture or surgically,” it’s like sitting on a waterbed that has a hole in it. “You’re going to start losing water from the disc, and that’s how a disc becomes degenerate.”

The resultant conditions of the disc and the waterbed are similar. Neither of them performs the duty for which they were designed. “If a waterbed doesn’t have enough water in it, when you sit on it, it’s going to herniate from the sides,” the doctor says, “and it’s not going to absorb shock anymore.”

“When there’s a disc herniation,” Dr. Benyamin continues, “a lot of times the yolk (nucleus) pushes the white and the shell (the layers of annulus fibrosus),” sometimes even protruding or essentially partially escaping the protective confines of the annulus fibrosus. “That’s called a disc herniation or protrusion,” the doctor adds.

With so much weight, pressure, and even torque exerting their respective forces upon such seemingly delicate structures, there is, naturally, a chance the intervertebral disc will again resemble an egg under too much pressure.

“You lift heavy weights, you fall, you’re in an accident—when you put too much pressure [on the egg], the outer shell cannot hold the inside of the egg anymore,” Dr. Benyamin explains. “That’s when the inner parts of the disc protrude. And, when they protrude the first thing that they come in contact with is a nerve—one of the spinal nerves—and that’s when you develop pain down your leg, commonly known as sciatica.”

Protecting those paradoxically strong but fragile discs in our backs is not always possible, particularly as we age. But there is help. As medicine becomes more adept at treating the result of herniation, it becomes better at preventing its recurrence.

For more information on intervertebral disc herniation, sciatica, and the methods used to treat them, please pick up next month’s copy of Healthy Cells Magazine to read “Walking on Eggshells, Part 2.”

Millennium Pain Center, located at 1015 S. Mercer Ave. in Bloomington, provides the most advanced and comprehensive pain management for a wide variety of conditions. For more information, you may contact them at 309-662-4321 or online at www.millenniumpaincenter.com.

Photo credit: Kondor83/iStock