Sciatic pain or sciatica is a very severe pain that radiates (spreads) from the lower back, down the back of the thigh and leg and can reach the foot. On many occasions the pain does not have this complete distribution, but reaches up to the knee or only in the buttock; on other occasions it manifests itself without pain, but with tingling (paresthesia), or in both ways. The distribution of the pain is very important, since it helps to know the origin and cause of the pain.
Sciatic pain is usually accompanied by low back pain, although sometimes low back pain is prior to sciatic pain and improves when sciatica appears. On many occasions there are previous episodes of low back pain (lumbar pain or lumbago).
Causes of sciatica
It is caused by irritation of the sciatic nerve, either by direct compression or by inflammation of the sciatic nerve, the nerve trunk or its roots. The most frequent cause is an entrapment of a nerve root at its exit from the spinal canal, either by a degeneration of the vertebrae (vertebral spondylosis) or by a degeneration of the intervertebral disc (disc herniation).
In most cases, the pain disappears spontaneously within four to six weeks. If after this time there has been no improvement, surgical intervention should be considered.
In case of loss of strength or sphincter disturbance, treatment should be more rapid. In the case of loss of sphincters, it should be urgent.
Diagnosis of sciatica
The main diagnostic method is magnetic resonance imaging. The most important thing is to know the type of pain, its distribution and the clinical examination obtained.
In turn, simple radiographs of the lumbar spine are useful in the case of suspected transitional anomalies and to clarify the presence of vertebral instability.
Neurophysiological analysis is not essential, although it may be useful for previously operated patients, in case of diagnostic doubts or to establish radicular damage prior to surgery.