Herniated Disc (Disk)

Picture of herniated disc between L4 and L5

The vertebrae are the bony building blocks of the spine. Between each of the largest parts (bodies) of the vertebrae are the discs. Ligaments are situated around the spine and discs. The spine has seven vertebrae in the neck (cervical vertebrae), 12 vertebrae in the mid-back (thoracic vertebrae), and five vertebrae in the low back (lumbar vertebrae). In addition, in the mid-buttock, beneath the fifth lumbar vertebra, is the sacrum, followed by the tailbone (coccyx).

The bony spine is designed so that vertebrae "stacked" together can provide a movable support structure while also protecting the spinal cord (nervous tissue that extends down the spinal column from the brain) from injury. Each vertebra has a spinous process, which is a bony prominence behind the spinal cord that shields the cord's nerve tissue. The vertebrae also have a strong bony "body" in front of the spinal cord to provide a platform suitable for weight-bearing.

The discs are pads that serve as "cushions" between the vertebral bodies that serve to minimize the impact of movement on the spinal column. Each disc is designed like a jelly donut with a central softer component (nucleus pulposus). Ligaments are strong fibrous soft tissues that firmly attach bones to bones. Ligaments attach each of the vertebrae and surround each of the discs. When ligaments are injured as the disc degenerates, localized pain in the area affected can result.

A herniated disc is not the same as a bulging disc. Although these terms are often confused with each other, there are few key differences between the two conditions.

Herniated disc

A herniated disc occurs when tears or ruptures in the outside of the annulus allow some soft material of the nucleus pulposus to exit the disc. The nucleus softens and spurts out through a tear in the annulus, meaning it is “non-contained.” It can extrude into the spinal canal, foramen, on either side of the disc or, in some rare cases, in multiple places (called multifocal extruded discs). This can compress a nerve root or the spinal cord. Typically, a disc that herniates is in the final stages of degeneration.

Bulging disc

A bulging disc occurs when the nucleus breaks through the annulus. This means that the disc protrudes outward, into the spinal canal, and can compress a nerve root. Bulging discs are considered to be “contained,” meaning that the disc is intact and has not broken open.

Cross-section picture of herniated disc between L4 and L5

As described above, each disc of the spine is designed much like a jelly donut. As the disc degenerates from age or injury, the softer central portion can rupture (herniate) through the surrounding outer ring (annulus fibrosus). This abnormal rupture of the central portion of the disc is referred to as disc herniation. This is commonly referred to as a "slipped disc."

The most common location for a herniated disc to occur is the disc at the level between the fourth and fifth lumbar vertebrae in the low back. This area is constantly absorbing the impact of bearing the weight of the upper body. This is especially important when we are standing or sitting. The lower back is also critically involved in our body's movements throughout the day, as we twist the torso in rotating side to side and as we hinge the back in flexion and extension while bending or lifting.

Risk factors for a herniated disc include degeneration of the spine and heavy lifting or bending of the spine.

The symptoms of a herniated disc depend on the exact level of the spine where the disc herniation occurs and whether or not nerve tissue is irritated. A disc herniation may not cause any symptoms. However, disc herniation can cause local pain at the level of the spine affected.

• If the disc herniation is large enough, the disc tissue can press on the adjacent spinal nerves that exit the spine at the level of the disc herniation. This can cause shooting pain in the distribution of that nerve and usually occurs on one side of the body and is referred to as sciatica. For example, a disc herniation at the level between the fourth and fifth lumbar vertebrae of the low back can cause shooting pain down the buttock into the back of the thigh and down the leg. Sometimes this is associated with numbness, weakness, and tingling in the leg. The pain often is worsened upon standing and decreases with lying down. This is often referred to as a "pinched nerve."
• If the disc herniation occurs in the cervical spine, the pain may shoot down one arm and cause a stiff neck or muscle spasm in the neck.
• If the disc herniation is extremely large, it can press on spinal nerves on both sides of the body. This can result in severe pain down one or both lower extremities. There can be marked muscle weakness of the lower extremities and even incontinence of the bowel and bladder. This complication is medically referred to as cauda equina syndrome.

The doctor will suspect a herniated disc when the symptoms described above are present. The neurologic examination can reveal abnormal reflexes. Often pain can be elicited when the straight leg is raised when lying or sitting. This is referred to as a "positive straight leg raising test." There can be an abnormal sensation in the foot or leg.

A variety of blood tests are frequently done to determine if there are signs of inflammation or infection.

Plain film X-rays can indicate "wear and tear" (degeneration) of the spine. They do not, however, demonstrate the status of discs. To determine whether or not a disc is herniated, an MRI scan or CT scan is performed for diagnosis. Sometimes a CT myelogram is used to further define the structures affected by a herniated disc. A CT myelogram is a CT that is performed after contrast dye is injected into the spinal canal. This allows for better visualization of the discs in certain cases. An electromyogram (EMG) can be used to document precisely which nerves are being irritated by a disc herniation.

Many different healthcare providers treat herniated discs. Usually, patients will see their primary care provider initially, who may be a general practitioner or specialist in internal medicine or family practice. Other physicians who frequently see patients with herniated discs include emergency-medicine physicians, pain management specialists, orthopedists, neurosurgeons, rheumatologists, and neurologists.

Picture of the stapled incision after surgery

Occasionally, disc herniation is incidentally detected when a test such as an MRI is performed for other reasons. If no symptoms are present, no particular treatment is necessary.

How do you fix a herniated disc?

Depending on the severity of symptoms, treatments for a herniated disc include physical therapy, muscle-relaxant medications, pain medications, anti-inflammation medications, local injection of cortisone (epidural injections), and surgical operations. In any case, all people with disc herniation should rest and avoid reinjuring the disc. Sometimes, even people with relatively severe pain early on can respond to conservative measures, including physical therapy with an exercise regimen, epidural cortisone injection, and/or oral cortisone medication (such as methylprednisolone or prednisone), without the need for surgical intervention.

There are now a variety of surgical approaches to treat disc herniation. Each type of operation is customized to the individual situation and depends a great deal on the condition of the spine around the disc affected. Surgical options include microdiscectomy using small surgical instruments and open surgical repair (either from a posterior or anterior approach). An urgent operation can be necessary when cauda equina syndrome is present (reviewed above).

How bad does a herniated disc have to be for surgery?

If you are not sure if your herniated disc requires surgery, here are five variables that assist doctors in deciding on appropriate treatment.

1. Persistent discomfort that did not respond to conservative care even after four to eight weeks
2. Lower limb weakness influencing mobility, whether standing or walking
3. Daily tasks are becoming difficult due to severe discomfort
4. Extreme numbness or tingling in the upper or lower limbs
5. Inability to control bladder or bowel movements

Home remedies for disc herniation can be very effective in relieving pain. These include over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen sodium (Aleve), as well as the application of heat and ice. Alternating heat and ice is very effective for pain relief for many people.

Activity modification is also important, which includes avoidance of activities that aggravate pain and may worsen nerve impingement. Bed rest and complete inactivity are unnecessary; they hinder recovery and are not advised.

Exercising is not advised for new symptoms of a herniated disc. On the other hand, building and maintaining strength in the back muscles and abdominal muscles is very important to prevent and treat chronic back problems. Exercises such as walking, physical therapy, and yoga have been proven to be very beneficial for those with chronic back pain.

Simple stretching can be very beneficial for symptoms of a herniated disc. Stretching should be started slowly and carefully. Stretching generally involves stretching the back in a backward bending position, called extension.

The outlook for a herniated disc depends on the severity and accompanying symptoms. While it is often possible to have a full recovery with conservative treatment measures, sometimes surgical intervention is necessary because of persistent symptoms.

A herniated disc can only be prevented by avoiding injury to the spine.