The spinal column is made up of bones called vertebrae that are stacked on top of each other to protect the nerves of the spinal cord. In between the stacked vertebrae are small rubbery discs that provide cushioning to keep the spine flexible and act as shock absorbers. The spinal discs are made up of a tough, outer shell (capsule) surrounding a jelly-like material (nucleus). When a disc becomes damaged by moving out of place or has a crack in the outer shell and leaks the soft jelly-like material, it becomes a herniated disc, also called a slipped disc or ruptured disc.

Symptoms

When spinal discs are damaged by injury, disease or the normal wear and tear associated with aging, they may bulge out of place (herniate) or break open (rupture). A herniated disc alone may not cause discomfort. Pain occurs when pressure is put on the nerve roots or spinal cord. Depending on the location of the herniated disc, symptoms will occur in the area of the body affected by the nerve.

Some symptoms may include:
Pain
Numbness
Weakness
Tingling ("pins and needles" sensation)

Symptoms may vary greatly, depending on the position of the herniated disc. A herniated disc in the neck may cause symptoms in the shoulders, arms or chest. A herniated disc in the lower back may cause sciatica, with leg pain and other nerve-related symptoms. A herniated disc in the lower back may be felt in the buttock and down the back of the leg to the ankle or foot. There may be low back pain, but usually not as severe as leg pain. Other symptoms of a herniated disc may include severe deep muscle pain and muscle spasms. Low back pain that does not involve numbness, tingling and/or weakness, or pain in a leg is not usually due to disc herniation pressing on the nerve root. In a similar manner, neck pain that doesn’t cause symptoms in the arm and hand is not usually from disc herniation.

Weakness in both legs and the loss of bladder and/or bowel control are symptoms of a specific and severe type of nerve root compression called cauda equina syndrome. This is a serious problem that requires immediate medical help.


Causes and Risk Factors

Degeneration of the disc (disc disease), aging or injury to the spine are common causes of herniated discs. Disc disease may result from tiny tears or cracks in the outer capsule of the disc.

Disc disease may develop as part of the normal aging process. Herniated discs can affect people of all ages, but they are most common in people between 35 and 45 years old who perform heavy manual labor or drive motor vehicles for long periods of time.

Injury to the spine can occur from sudden heavy strain or increased pressure to the lower back. Repeated activities such as poor lifting habits, prolonged exposure to vibration or sports-related injuries may stress the lower back.

Diagnosis

The doctor will take a medical history and conduct a physical exam to determine if a herniated disc is causing a patient’s symptoms.

Diagnostic tests may be ordered, such as a magnetic resonance imaging (MRI) scan to confirm the location and seriousness of a herniated disc or to look for another condition, such as an infection or tumor. An MRI provides detailed images of the soft tissues of the spine, including the muscles, tendons, ligaments and discs. Computed tomography (CT) scans also may be ordered to provide detailed images of bony structures of the spine. A myelogram, using dye to show the bones, nerves and spinal cord, can be examined for abnormalities in the spine.

Electromyography (EMG) can be used to diagnose diseases that damage muscle tissue, nerves or the points where nerve and muscle join. This test is useful in determining if there has been prolonged pressure on a nerve root.

X-rays will not show a herniated disc. However, they will be taken if the doctor suspects a more serious underlying condition (such as a tumor, infection or severe nerve damage), or if leg pain and other symptoms do not improve after two to four weeks of nonsurgical treatment. Other tests, such as blood tests, may also be ordered to rule out other conditions.


Treatments

The goals of treatment for herniated discs are to relieve symptoms and prevent further injury. Rest followed by a gradual increase in activity and medication to control pain and inflammation are examples of common nonsurgical treatments.

Patients with low back pain that does not include leg symptoms and neck pain without arm or hand involvement are not considered candidates for surgery. Even when a herniated disc is causing nerve root compression, surgery is usually not the best course of action.

Improvement is seen in more than 70 percent of patients within three months, and more than 90 percent of patients with a herniated disc will improve in six months without surgery. For this reason, nonsurgical treatment is usually tried before surgery is considered.

In some cases, herniated discs heal by a process called resorption. During resorption, the body absorbs parts (fragments or tissue) from a herniated disc that has ruptured.

A doctor or physical therapist may recommend exercises to reduce pain and strengthen the muscles that support the back to avoid further injury. Surgery may be considered for people who have progressive nerve damage or severe weakness or numbness, or for those whose nerve root pain has not been relieved by other methods.