ISSN: 1391 - 0531
Sunday, December 17, 2006
Vol. 41 - No 29


By Esther Williams

Troubled by recurring back pain? Does the pain begin at the lower back, travel to the buttocks and shoot down to below the knee and then to the calf, ankle, foot or toes? These back pain symptoms could signal nerve irritation. You may just be suffering from sciatica.

"Sciatica is defined as pain, numbness or tingling sensation down the leg as a result of irritation of the sciatic nerve," explains Consultant Rheumatologist, Dr. Lalith Wijayaratne.

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The largest nerve in the human body is the sciatic nerve formed by nerves coming out of the spinal cord in the lower back region. It is responsible for sending critical nerve impulses between the brain and the leg.

The vertebral column is one of the most vital parts of the body, giving an erect posture, determining our height and supporting our trunks and making all our trunk movements possible. It comprises many pieces of bone piled on top of each other separated by inter-vertebral discs that cushion the bones. These discs resembling carrom board pieces in shape are tough and fibrous on the outside and soft as toothpaste on the inside, their two-fold purpose being flexibility (between bones of the spine) and acting as shock absorbers.


Causes for sciatica

Pressures beyond what the spine can handle caused by bending, lifting or injury can crack the outer layer of a disc causing the soft centre (nucleus pulposus) to leak out, also referred to as disc prolapse. Such a prolapse can press the sensitive nerves and cause a severe reaction such as swelling and irritation. This is the commonest cause for sciatica that occurs both in men and women of ages 20-45 though commoner in men. Sciatica can also occur among those above 50 for the following reasons: When total water content in the body reduces during the natural process of aging, the discs also get dried up disabling their ability to act as shock absorber. Normal wear and tear during old age can also cause the disc to become dry and less shock absorbent resulting in Lumbar Spondulosis; It is also common as you age for bones to grow new pieces or for there to be a general narrowing of the spinal cord leading to canal stenosis, both of which add to the pressure of nerves resulting in a prolapse. Finally, on rare occasions a tumour or cancerous growth can bring about similar results. Disc prolapses can occur suddenly or gradually depending on the cause. Symptoms according to Dr. Wijayaratne include pain, numbness and tingling in the legs and feet, normally on one side. The condition can also cause weakness in the calf, ankle, foot, toe and difficulty in walking. When symptoms get worse, one may experience discomfort in sitting or standing for long.

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Patients discover that while lying flat can provide some relief, bending and picking things from the floor, can cause excruciating pain.


Early and accurate diagnosis is vital for successful treatment. Dr. Wijayaratne specifies a process that includes recording the history of the patient and examining nerves on both spine and leg. If a patient does not respond to anti-inflammatory drugs and pain killers, a special X-ray or an MRI (Magnetic Resonance Imaging) scan may be required. While an X-ray only reveals bones and joints, MRI is an imaging technique that uses magnetic fields and pulses of radio wave energy to show soft structures - tissues, nerves, discs and ligaments of the spine and muscles. Doctors recommend an MRI only if they need further information or when faced with uncertain circumstances.


"Fortunately, many can have complete recovery," Dr. Wijayaratne assures. Initial treatment comprises advice on back discipline (to relieve spine of load), anti- inflammatory drugs to bring down swelling and painkillers. Occasionally the doctor may advise using ice or fomenting the area of pain. If severe pain persists, the patient may be advised bed rest.

To enable healing of the tear in the disc, patients may be asked to control laughing, sneezing and coughing as those actions can strain the discs. However, treatment is not complete without exercise to the back covering two main aspects: Stretching of muscles and ligaments and strengthening of back and stomach muscles to support and stabilize the spine. For acute sciatica, management may include injecting the spine with steroids (epidural injections) to shrink swollen tissues that cause pressure on nerves. This is done right at the onset if pain does not respond to injections and drugs. Surgery is indicated rarely for complications that may cause blocking of passage of urine or faeces. However, as "recurrence is common, patients would have to adhere to posture discipline," Dr. Wijayaratne warns.

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Copyright 2006 Wijeya Newspapers Ltd.Colombo. Sri Lanka.