Sciatica

Definition

Sciatica refers to pain, weakness, numbness, or tingling in the leg. It is caused by injury to or compression of the sciatic nerve. Sciatica is a symptom of another medical problem, not a medical condition on its own.

Causes, incidence, and risk factors

Sciatica occurs when there is pressure or damage to the sciatic nerve. This nerve starts in the spine and runs down the back of each leg. This nerve controls the muscles of the back of the knee and lower leg and provides sensation to the back of the thigh, part of the lower leg, and the sole of the foot.

Common causes of sciatica include:

• Piriformis syndrome (a pain disorder involving the narrow piriformis muscle in the buttocks)
• Slipped disk
• Degenerative disk disease
• Spinal stenosis
• Pelvic injury or fracture
• Tumors

Symptoms

Sciatica pain can vary widely. It may feel like a mild tingling, dull ache, or a burning sensation. In some cases, the pain is severe enough to make a person unable to move.

The pain most often occurs on one side. Some people have sharp pain in one part of the leg or hip and numbness in other parts. The sensations may also be felt on the back of the calf or on the sole of the foot. The affected leg may feel weak.

The pain often starts slowly. Sciatica pain may get worse:

• After standing or sitting
• At night
• When sneezing, coughing, or laughing
• When bending backwards or walking more than a few yards, especially if caused by spinal stenosis

Signs and tests

Sciatica might be revealed by a neuromuscular examination of the legs by a physician. There may be weakness of knee bending or foot movement, or difficulty bending the foot inward or down. Reflexes may be abnormal, with weak or absent ankle-jerk reflex. Pain down the leg can be reproduced by lifting the leg straight up off the examining table.

Tests are guided by the suspected cause of the dysfunction, as suggested by the history, symptoms, and pattern of symptom development. They may include various blood tests, x-rays, MRIs, or other tests and procedures.

Treatment

Because sciatica is a symptom of another medical condition, the underlying cause should be identified and treated.

In some cases, no treatment is required and recovery occurs on its own.

Conservative treatment is best in many cases. Your doctor may recommend the following steps to calm your symptoms and reduce inflammation.

• Apply heat or ice to the painful area. Try ice for the first 48 - 72 hours, then use heat after that.
• Take over-the-counter pain relievers such as ibuprofen (Advil, Motrin IB) or acetaminophen (Tylenol).
• While sleeping, try lying in a curled-up, fetal position with a pillow between your legs. If you usually sleep on your back, place a pillow or rolled towel under your knees to relieve pressure.

If at-home measures do not help, your doctor may recommend injections to reduce inflammation around the nerve. Other medicines may be prescribed to help reduce the stabbing pains associated with sciatica.

Physical therapy exercises may also be recommended. Additional treatments depend on the condition that is causing the sciatica.

Nerve pain is very difficult to treat. If you have ongoing problems with pain, you may want to see a neurologist or a pain specialist to ensure that you have access to the widest range of treatment options.

Expectations (prognosis)

If the cause of the sciatic nerve dysfunction can be identified and successfully treated, full recovery is possible. The extent of disability varies from no disability to partial or complete loss of movement or sensation. Nerve pain may be severe and persist for a prolonged period of time.

Complications

• Partial or complete loss of leg movement
• Partial or complete loss of sensation in the leg
• Recurrent or unnoticed injury to the leg
• Side effects of medications

Calling your health care provider

Call your doctor right away if you have:

• Unexplained fever with back pain
• Back pain after a severe blow or fall
• Redness or swelling on the back or spine
• Pain traveling down your legs below the knee
• Weakness or numbness in your buttocks, thigh, leg, or pelvis
• Burning with urination or blood in your urine
• Pain that is worse when you lie down, or awakens you at night
• Severe pain and you cannot get comfortable
• Loss of control of urine or stool (incontinence)

Also call if:

1. You have been losing weight unintentionally
2. You use steroids or intravenous drugs
3. You have had back pain before but this episode is different and feels worse
4. This episode of back pain has lasted longer than 4 weeks

If any of these symptoms are present, your doctor will carefully check for any sign of infection (such as meningitis, abscess, or urinary tract infection), ruptured disk, spinal stenosis, hernia, cancer, kidney stone, twisted testicle, or other serious problem.

Prevention

Prevention varies depending on the cause of the nerve damage. Avoid prolonged sitting or lying with pressure on the buttocks.

References

Clarke JA, van Tulder MW, Blomberg SE, et al. Traction for low-back pain with or without sciatica. Cochrane Database Syst Rev. 2007;(2):CD003010.

Chou R, Qaseem A, et al. Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society. Ann Intern Med. 2007;147(7):478-491.