Herniated Disks

Herniated disks are most common in the lumbar spine--the part of your backbone between the bottom of your ribs and your hips. Disks are the soft "cushions" between the bones of the spine. The disks in the spine let you move your backbone.

When a disk between two bones in the spine presses on the nerves around the backbone, it's called a herniated disk. Also called a ruptured or slipped disk or a herniated nucleus pulposus, a herniated disk occurs when all or part of the nucleus pulposus-the soft, gelatinous, central portion of an intervertebral disk - is forced through the disk's weakened or torn outer ring (anulus fibrosus).

When this happens, the extruded disk may impinge on spinal nerve roots as they exit from the spinal canal or on the spinal cord itself, resulting in back pain and other signs of nerve root irritation. Herniated disks usually occur in adults (mostly men) under age 45.

Causes

Herniated disks may result from severe trauma or strain or may be related to intervertebral joint degeneration. In older patients, whose disks have begun to degenerate, minor trauma may cause herniation. About 90% of herniated disks occur in the lumbar and lumbosacral regions, 8% occur in the cervical area, and 1 % to 2 % occur in the thoracic area.

Patients with a congenitally small lumbar spinal canal or with osteophyte formation along the vertebrae may be more susceptible to nerve root compression with a herniated disk and more likely to have neurologic symptoms.

Signs and symptoms

The most common symptoms are:

• back pain
• pain, numbness, tingling or weakness of the leg.

The pain and numbness of the leg occurs when the herniated disc presses on the nerves in the spine.

Diagnosis

To diagnose a herniated disk, give the doctor your complete medical history. Tell him or her if you have neck/back pain with gradually increasing arm/leg pain. Tell the doctor if you were injured. The doctor will physically examine you. This can determine which nerve roots are affected (and how seriously). A simple X-ray may show evidence of disk or degenerative spine changes. MRI (magnetic resonance imaging) or CT (computed tomography) scans (imaging tests to confirm which disk is injured) or an EMG (a test that measures nerve impulses to the muscles) may be recommended if pain continues.

Treatment

Treatment measures are initially conservative and consist of several weeks of bed rest (possibly with pelvic traction), heat applications, an exercise program, and medication. If neurologic impairment progresses rapidly, surgery may be necessary.

Drug therapy

Aspirin reduces inflammation and edema at the site of injury; rarely, corticosteroids such as dexamethasone may be prescribed for the same purpose. Muscle relaxants, especially diazepam or methocarbamol, also may be beneficial.

Herniated Disk Surgery

A herniated disk that fails to respond to conservative treatment may necessitate surgery. The most common procedure, laminectomy, involves excision of a portion of the lamina and removal of the protruding disk.

If laminectomy doesn't alleviate pain and disability, a spinal fusion may be necessary to overcome segmental instability. Laminectomy and spinal fusion are sometimes performed concurrently to stabilize the spine.

Other treatments

Chemonucleolysis-injection of the enzyme chymopapain into the herniated disk to dissolve the nucleus pulposusis a possible alternative to laminectomy. Microdiskectomy can also be used to remove fragments of the nucleus pulposus.

Prevention

Proper exercises to strengthen the lower back and abdominal muscles are key in preventing excess stress and compressive forces on lumbar disks. Good posture will help prevent problems on cervical, thoracic, and lumbar disks. A good flexibility program is critical for prevention of muscle and spasm that can cause an increase in compressive forces on disks at any level. Proper lifting of heavy objects is important for all muscles and levels of the individual disks. Good posture in sitting, standing, and lying down is helpful for the spine. Losing weight, if needed, can prevent weakness and unnecessary stress on the disks caused by obesity . Choosing proper footwear may also be helpful to reduce the impact forces to the lumbar disks while walking on hard surfaces. Wearing special back support devices may be helpful if heavy lifting is required with