The first symptoms of stenosis include bouts of low back pain. After a few months or years, this may progress to claudication. The pain may be radicular, following the classic neurologic pathways. This occurs as the spinal nerves or spinal cord become increasingly trapped in a smaller space within the canal. Determining whether pain in the elderly is caused by lack of blood supply or stenosis is difficult; testing can usually differentiate between them, but patients can have both vascular disease in the legs and spinal stenosis.