Spinal stenosis is a narrowing of the space that houses the spinal column. The condition may be caused by anatomical changed in the vertebrae and discs that protect the spinal cord, or by changes to other nearby structures that change and encroach into the canal that protects the spinal cord. In a healthy spinal cord, the spinal cord itself travels from the brain to the first or second lumbar vertebrae though the intervertebral foramina of each vertebral bone. When the whole process is healthy, there is enough room for the spinal cord to travel through safely, and there is no impingement on the canal laterally. A number of degenerative changes can cause a narrowing in the spinal column.
When everything is working right and there is no damage to any of the working sections around the spinal column, the spinal cord remains free to send and receive messages, and for us to feel and respond to our environment. When everything is working right, there is just enough space for the spinal cord and nerve roots that emanate from it to function without interruption. When any type of pathological changes do occur, the spinal cord and nerve root may become pinched, and we would feel that pinch in the form of pain or some type of sensory dysfunction (e.g. numbness, tingling). If the pinch gets serious enough, someone could experience severe back pain or even loss of strength in the limbs. Patients who experience this problem should act quickly to treat this problem. Treatments for spinal stenosis may include behavior modification, epidural injections, exercises, foraminotomy, and laminectomy. Laminectomy and foraminotomy are surgical procedures that are usually measures of last resort. Most surgical procedures for back pain conditions are only considered after other more conservative treatments (such as physical therapy) have failed.
When the spinal structure is sound, the spinal cord travels through the intervertebral foramina and the nerve roots exit the spine and extend to other areas of the body. If the nerve root that extends to the left foot has been impacted, then a person may experience the symptom of numbness/burning in their left foot. Space is pretty tight in this area around the spinal cord, and any degeneration/inflammation in the area can cause an impingement into it. Pathological changes could come from the vertebral bone itself if the lamina (the vertebra's bony plate) thickens. Tendons or ligaments may become displaced or enlarged. Bone spurs (osteophytes) may grow on the vertebral bones towards the spinal canal, further narrowing this narrow corridor for the chord and nerve roots to travel. A herniated disk may bulge and move into the canal. Paget's disease is a rare disease that causes bones to grow to an abnormal width (larger).
Common symptoms of spinal stenosis include back pain that is made worse by strenuous exercise or unusual bends forwards or backwards from what they would normally do for everyday activities. Patients who are affected are more deliberate in their movements so as not to aggravate their movements and avoid bending too far forward or backwards from the waist.