Lumbar spinal stenosis is a common problem in the aging adult population. Degenerative changes in the spine cause narrowing of the spinal canal. This leaves less room for the spinal cord and spinal nerve roots. In the lumbar spine, pressure on the nerve roots can cause very debilitating symptoms.
At the bottom of the spinal column the nerve roots converge together in what's called the cauda equina. This literally means "horse's tail" because that's what the bundle of nerves looks like. Stenosis causing blockage of the nerves in this area can cause bladder changes and severe muscle atrophy and weakness.
The treatment of LSS remains a hotly debated topic in medical circles. Studies have not been able to show one treatment works best for all patients. It's more of a trial-and-error basis at this point. What works for one person may not work for another.
Encourage your mother to keep going back to her doctor and/or physical therapist. There's a good chance they will be able to find the right combination that works for her. Surgery works best for some patients. Anyone with motor and bladder problems from the cauda equina is a good candidate for surgery before permanent damage occurs.