Sciatica – What is it?

Sciatica is a term often used to describe any pain down the leg. However, there are numerous causes of leg pain and Sciatica is a specific diagnosis. The sciatic nerve exits the spine at the lower back level, runs through the buttock muscles and travels down the back of the leg, passes the back of the knee and ends at the back of the foot. Irritation of this nerve at any point along its path may cause leg pain, however true sciatica is caused by nerve root irritation as it exits the spine (termed radiculopathy). The most common cause of sciatic nerve root irritation, seen in those with true Sciatica, is a disc herniation. A disc herniation (also known as disc bulge) occurs when the inner ‘jelly substance’ of the disc is ‘pushed out’ of its normal boundaries and out through the outer fibrous ring. Nerve roots are closely situated to the discs and vertebrae so can easily become irritated during a disc herniation. Nerve roots can become irritated due to the inflammation and increased blood flow from the disc injury. However, nerve roots can also become irritated if the ‘jelly substance’ during the disc herniation compresses a nerve root.  A herniated disc may result from an acute incident, or more commonly, it occurs gradually over time with repetitive strain to the spine.

Symptoms of sciatica include pain down the leg, weakness of the muscles of the affected leg, altered sensation (such as pins and needles, numbness). The pain is often described as a ‘shooting’ pain and may disturb sleep. Movements that aggravate sciatica are movements that increase the pressure on the disc herniation such as bending forward, sitting for long periods, driving, lifting.

If you are experiencing any leg pain, please visit your physiotherapist. Your physiotherapist will first conduct an assessment to identify whether your leg pain is in fact sciatica or whether you are experiencing another cause of leg pain. Other causes of leg pain include facet joint pathology and piriformis syndrome. Facet joint pathology such as stiff and irritated facet joints as well as osteophytes (bone spurs seen in those with low back arthritis) can cause nerve irritation and leg pain. Piriformis syndrome is used to describe the compression of the sciatic nerve as it passes through the piriformis muscle (a muscle deep in the buttock). In a small percentage of people, the sciatic nerve passes in the middle of the piriformis muscle (instead of just below it) so if this muscle gets tight or spasms up, the sciatic nerve can get compressed resulting in leg pain. Physiotherapy can be very beneficial for the treatment of sciatica, as well as the other causes listed above. Treatment of sciatica may include soft tissue massage to any muscle spasm, joint mobilisation to restore full movement, posture advice and a home exercise program consisting of specific stretches and strengthening exercises to restore full strength and prevent further recurrences.

By Jessica Norton

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