Infections
An epidural abscess is a series of pus that occurs between the membrane of your spinal cord and the bones of your spine. In most cases, it may result in swelling that exerts a force on your nerves. The exertion of force on your nerves may lead to sciatica.
Wear and tear
Spinal stenosis occurs when the spaces in your spine become smaller. It is caused by wear and tears on your spine. Since spinal stenosis involves the narrowing of the spine, it can compress your nerve, which can also result in sciatica.