Lumbar stenosis is a degenerative condition. It can occur organically.
Spinal stenosis is not caused by an injury.
Spinal stenosis refers to narrowing within the spinal canal, which can be mild, moderate, or severe. The classification is based on advanced imaging studies that measure the diameter of the spinal canal.
Pain from spinal stenosis co-occuring with pain after an accident has a damages component. The clinical physician will treat the disease and treat pain. Parsing out causation does not have the same meaning to the treater that it does to an Expert Witness.
A degenerative disease, per se, is not caused directly by an accident. It can be made worse, or damage accelerated by spinal trauma.