Although in clinical practice the most common site for a disc herniation is the lumbar spine, the cervical spine is affected frequently. The thoracic spine although not as common, is nevertheless affected tool.
Disks are soft, rubbery pads found between the hard bones (vertebrae) that make up the spinal column. In the middle of the spinal column is the spinal canal; a hollow space that contains the spinal cord and other nerve roots. The disks between the vertebrae allow the back to flex or bend. Disks also act as shock absorbers.
The outer edge of the disk is a ring of gristle-like cartilage called the annulus. The center of the disk is a gel-like substance called the nucleus. A disk herniates or ruptures when part of the center nucleus pushes the outer edge of the disk into the spinal canal, and puts pressure on the nerves.
What Causes a Disc to Herniate?
As the aging process takes a toll on our bodies, the discs are also affected. The capacity of the nucleus to retain water is decreased, causing a redistribution of the stress loads to the annulus. Eventually the annulus weakens allowing the gel to come through. Other factors involve are: wear and tear, excessive weight, bad posture, improper lifting and sudden increase in pressure (trauma, heavy lifting, etc).
The fibrous outer ring may tear. As the disk material pinches and puts pressure on the nerve roots, pain results. Sometimes fragments of the disk enter the spinal canal where they can damage the nerves that control bowel and urinary functions.
Because of the multiple causes of neck and low back pain, disc herniations are just one of the potential causes. The most common symptom of a herniated disk in the lower extremity is sciatica, a sharp, often shooting pain that extends from the buttocks down the back of one leg. In the cervical spine it can cause arm pain and if severe enough leg pain. Other symptoms include:
- Weakness (arm or leg)
- Tingling (a “pins-and-needles” sensation) or numbness in one or more extremity
- Loss of bladder or bowel control (If you also have weakness in both legs, you could have a serious problem. Seek immediate attention.)
- A burning pain centered in the back and neck
Your medical history is key to a proper diagnosis. You may have a history of back pain with gradually increasing leg pain. Often a specific injury causes a disk to herniate. A physical examination can usually determine which nerve roots are affected (and how seriously). A simple x-ray may show evidence of disk or degenerative spine changes.
Conservative treatment usually works. Most back pain will resolve gradually with simple measures. Bed rest (48 hours) and over-the-counter pain relievers may be all that’s needed. Muscle relaxants, analgesic and anti-inflammatory medications are also helpful. You can also apply cold compresses or ice for no more than 20 minutes at a time, several times a day. After any spasms settle, you can switch to gentle heat applications.
Any physical activity should be slow and controlled so that symptoms do not return. Take short walks and avoid sitting for long periods. Exercises, such as those described in the Specific neck and low back exercises, may also be helpful in strengthening neck, back and abdominal muscles. Learning to stand, sit, and lift properly is essential to avoiding future episodes of pain.
Pain Management Interventions
MRI or CT scans (imaging tests to confirm which disk is injured) or an EMG (a test that measures the electrical activity of muscle contractions to show nerve or muscle damage) may be recommended if pain continues. Provocative discography, under certain circumstances, remains an excellent diagnostic tool when the above tests are inconclusive in determining the specific pain source.
Most patients improve with conservative therapy. When the pain persists, in spite of aggressive physical therapy and medication management, pain management interventions (by a specialist in spine therapeutic and diagnostics) are indicated. Procedures such as epidural steroid injections (cervical, lumbar and thoracic) are frequently perform in order to decrease the inflammatory changes in the nerve root. Most patients tend to respond favorably to these interventions and no further treatment, besides a maintenance exercise program is recommended.
Less than 20% of the patients fail to respond to conservative therapy and pain management interventions. These patients are considered candidates for surgical intervention. Emergency surgery is indicated when there is sudden loss of bladder or bowel function, significant neurologic deficits and intractable severe pain not responding to interventions.
Minimally Invasive Interventions such as percutaneous disc decompression via Nucleoplasty, Dekompressor, Laser or Endoscopic discectomy are performed with increase frequency. These procedures are indicated in-patient with small disc herniations, mild to moderated loss of disc space and no significant neurological deficits.
Surgery may be required if a disk fragment lodges in spinal canal and presses on a nerve, causing a loss of function. The traditional surgical treatment is called a Laminectomy and involves removing a portion of the vertebral bone. The surgery is performed under general anesthesia with an overnight hospital stay.