Pathophysiology, clinical presentation, natural history, and review of the SPORT trials

Lumbar spinal stenosis is a combination of intervertebral disk degeneration (leading to loss of normal disk height), facet joint hypertrophy, ligamentum flavum hypertrophy/infolding, and osteophyte formation that results in narrowing of the spinal canal and compression of the lumbo-sacral nerve roots. This mechanical compression presents in patients as neurogenic claudication and resultant back and leg pain. Spinal stenosis is most commonly seen in the elderly population secondary to the normal aging of the lumbar spine. However, some patients may be predisposed to its effects due to congenitally narrowed canal secondary to short pedicles. The literature describes a variable natural history with a general worsening over time. Recently, more has been learned about the natural history of lumbar spinal stenosis with the addition of the Spine Patient Outcomes Research Trial (SPORT) to the literature.