Hello, I have gone through your query and understand your concern. As you have spinal stenosis, it think it could be the cause for your weakness in left leg. You have lumbar canal stenosis. that is why you have symptoms pertaining to lower limbs. Now the bone spurs or the disc may compress the nerves in the spinal cord supplying the left lower limb. That is why you have weakness in left leg. As you have weakness, it could be treated only by removing the part of the bone or spine compressing the nerve. Thus you may need surgery to remove the bone spurs or dicc. It can be done by a procedure called laminectomy and spinal fusion. After surgery, your doctor may give a brace like that one you are having for right leg. He may advice physical therapy and other stretching exercises to maintain good quality of life. Hope this helps. Please write back for further queries. Wishing you good health.