The Many Causes of Sciatica
Sciatica is defined as pain caused by compression of the sciatic nerve anywhere along its course. The pain is described as burning, lancinating or stabbing and travels from the buttock, down the back of the leg and past the knee. There may also be associated muscle weakness, numbness, tingling or prickling down the leg and into the foot. It has been estimated that approximately 40% of New Zealanders will experience sciatica at some point in their lives.
The sciatic nerve is the largest nerve in the body, at a whopping 2cm thick and supplies the back of the leg, part of the adductor muscles, and the muscles of the lower leg and foot. It typically originates from the L4 to S3 spinal nerves, travels underneath the piriformis muscle, down the back of the leg and splits into two nerves at the back of the knee. Because this nerve is so large and supplies so much of the leg a diagnosis of “sciatica” is not very helpful in telling us exactly what is wrong.
Four of the most common causes of sciatic nerve compression are protruding disk, narrowing of the spinal canal, bony spurs where the nerve roots exit the spine and tightness of the piriformis muscle. Each one of these causes would require a different clinical approach to treatment. Recognising which cause is responsible is paramount to successful self help.
A herniated disk may cause an increase in pain with an increase in abdominal pressure caused when coughing or going to the toilet. Diagnosis is most likely via MRI. Musculoskeletal therapy, maintaining core stability, reducing muscular tightness in the lower back and specific exercises may reduce symptoms significantly. Surgery may be required in extreme cases.
Narrowing of spinal canal and bony spurs are most commonly degenerative in cause and diagnosed via X-ray. Specialist referral and surgical treatment may be required depending on the severity although musculoskeletal therapy and exercise has a valuable role to play.
Piriformis tightness is usually functional in cause can be relieved by specific stretches, massage and addressing any pelvic imbalances.
So, as you can see, sciatica is a “catch all” description that covers many causes of leg pain and may cause significant disability. If you are suffering from back or leg pain don’t suffer needlessly, consult your health care professional who will be able to effectively diagnose the cause of your sciatica and offer effective treatment and advice.