Lateral spinal stenosis generally results in symptoms that are directly related to compression of the nerve roots at the level of the stenosis. Both pain and muscular weakness may result from hypertrophy of the facet joints, spondylosis deformity, bulging of the disc annulus, or herniation of the nucleus pulposus. Although large central disc herniations occur, most extruded disc fragments migrate laterally, and some disc fragments move to a position that is superior or inferior to the interspace.

Many patients with lumbar spinal stenosis (LSS) show symptomatic and functional improvement or no changes over time. In one study, 90% of 169 untreated patients with suspected lateral recess stenosis improved symptomatically after 2 years. A 4-year study of 32 patients treated conservatively for moderate stenosis reported unchanged symptoms in 70% of patients, improvements in 15%, and worsening in 15%. Walking capacity improved in 37% of patients, remained unchanged in 33% and worsened in 30%.

The natural history of LSS is not well understood. A slow progression appears to occur in all affected individuals. Even with significant narrowing, such persons are very unlikely to develop an acute cauda equina syndrome in the absence of significant disk herniation. A slow progression of dysfunction in the lumbar spine often leads to a feeling of heaviness in the legs that is only relieved by periods of rest. Infrequently, a facet joint synovial cyst leads to severe canal stenosis and the development of subacute radiculopathy, often characterized by pain and mild weakness. This may develop as a result of trauma or arthritic changes in the facet joint.