Lumbar spinal stenosis
This is also a very common condition related to the ageing process in the spine. The facet joints and ligament can enlarge and press on the spinal nerves as they pass this area. In some people, this can result in a constant sciatica. In others, they may be painfree when sitting down but, as soon as they try to stand or walk they develop gradually worsening pain and aching in the legs which requires them to sit down frequently (claudication).
Some people have one or two episodes then the pain resolves whilst other people find that modifying activities provides enough relief for them to carry on with fairly normal activities. However, some people have worsening pain and are very limited by their symptoms and are suitable for an operation. A decompression operation often provides excellent relief of the pain.