My father has been diagnosed with lumbar spinal stenosis. He complains of pain when walking and bends forward to relieve the pain. What is happening to cause these symptoms?

Stenosis means a closing or narrowing of a space. In the spine, there is an opening from the neck to the base of the spine. The spinal cord passes through this canal. As we age, changes in the spine cause this space to get smaller.

Narrowing of the space puts pressure on the spinal cord and spinal nerves as they exit the cord. This causes pain, numbness, and weakness in the low back and legs. Bending forward opens the space. Extending the spine backwards narrows it even more.

At the same time, there can be a decrease in blood flow to the nerves and spinal cord. Other soft tissue in the area also gets pinched. Both of these factors add to the painful symptoms.