Lumbar spinal stenosis (LSS) implies spinal canal narrowing with possible subsequent neural compression. Although the disorder often results from acquired degenerative changes (spondylosis), spinal stenosis may also be congenital in nature. In some cases, the patient has acquired degenerative changes that augment a congenitally narrow canal. The canal components that contribute to acquired stenosis include the facets (hypertrophy, arthropathy), ligamentum flavum (hypertrophy), posterior longitudinal ligament (ossification of posterior longitudinal ligament [OPLL]), vertebral body (bone spurs), intervertebral disk, and epidural fat. Congenital stenosis may predispose an individual with mild degenerative changes to become symptomatic earlier in life.