When something protrudes centrally toward the interior portion of the vertebra, where the spinal canal lies, the canal may narrow, placing pressure on the spinal cord (spinal stenosis). The spinal canal is the open channel in the stacked vertebral bones through which spinal cord travels. The spinal cord is comprised of nerves exiting the brain and communicating to rest of the body. For example, the brain commands the leg to move via the spinal cord. An arthritic extra bone growth/osteophyte/bone spur may intrude into the canal and place pressure on the spinal cord, but disks, cysts, or an inflamed ligament may also produce this narrowed canal/spinal cord pressure (spinal stenosis).
Spinal stenosis peaks later in life. The back pain it causes is usually more mild or dull. Only occasionally does spinal cord irritation cause low back pain. Most symptoms/complications arise from spinal cord tail irritation. As with sciatica, nerve-type leg or foot pain (burning, electric, sharp-shooting, numb/tingling), usually down both legs, occurs with or without leg weakness. If the motor nerves commanding the legs to move are damaged, weakness may ensue, possibly leading to disuse/atrophy. Classically, walking and prolonged standing cause leg weakness, numbness and fatigue. Older people with this condition often lean over shopping carts while walking to relieve the spinal pressure and improve mobility. Rest fails to immediately resolve these pains, and somewhat long breaks are needed during longer walks. Conventional treatment includes exercise and medication, but surgery is definitive and necessary if bowel or bladder dysfunction develop.