In lumbar stenosis, the spinal nerve roots in the lower back are compressed, or choked, and this can produce symptoms of sciatica -- tingling, weakness or numbness that radiates from the low back and into the buttocks and legs - especially with activity.
Spinal stenosis pain in the neck (cervical spinal stenosis) can be far more dangerous by compressing the spinal cord. Spinal cord stenosis may lead to serious symptoms, including major body weakness or even paralysis. Such severe spinal stenosis symptoms are virtually impossible in the lumbar spine, however, as the spinal cord is not present in the lumbar spine.
In rare cases, lumbar stenosis can go no further than to produce severe persistent disabling pain and even weakness in the legs. Most cases of stenosis in the lumbar spine, however, have pain that radiates into the leg(s) with walking, and that pain will be relieved with sitting. This is called claudication, which can also be caused by circulatory problems to the legs.
Source : spin-health.com