Wecome to HCM
Your mother is having chronic low back pain
for almost 1 year,radiating to left lower leg ,she may be suffering from radiculopathy
that means nerve roots are compressed by degeneratve changes in back bone or disc is degenrated and prolapse and causes pain.
You visit a Orthopedic surgeon or Neurologist
after examination a MRI spine will give exact cause of pain and then if compression is more or neurological deficit is there surgical decompression may be required.
as she is 50 years perimenopausal hot fluses are due to hormonal changes which also may be cause for osteoporosis
and back pain for that agynaecological examination with a abdominal ultrasound
examination is helpful.
Go for complete medical check her problem once diagnosed can be treated
good luck to her.