The term LSS encompasses a number of conditions that decrease the total area of the central spinal canal, lateral recess, or intervertebral foramen. Although there may be visual evidence of narrowing of these osseous structures on x-ray, MRI or CT scans, symptomatic LSS is characterized by neurogenic claudication and/or radiculopathy . Interestingly, the severity of bony narrowing measured on MRI or CT does not correlate with the severity of patient symptoms, including the hallmark symptom of the clinical syndrome: significant leg pain that typically worsens with ambulation.