Lumbar Spinal Stenosis

Lumbar spinal stenosis is a result of aging and everyday wear and tear on the spine. Though these changes happen to all of us, not everyone will experience the symptoms of lumbar spinal stenosis (LSS). Features of LSS include persistent, progressive low back pain with or without radiation, numbness or weakness in the buttocks and legs, and symptoms that improve with resting, lying down or bending forward. Unfortunately, many patients with symptoms of spinal stenosis often suffer for a long period of time before seeking medical advice and, even then, can often be misdiagnosed and treated inappropriately. As such, many older people with LSS have had to give up active lifestyles despite conservative treatment with rest, medication, and physical therapy.

What Happens in Lumbar Stenosis?

In the normal spinal canal, the nerve roots are contained in the thecal sac and exit between each vertebra (foramina). The central spinal canal and the foramen contain the thecal sac and nerve roots respectively.

Figure 1

The canal and foramen are formed (Figure 1) by bony structures (vertebral body, facets, pedicles) as well as soft tissue structures (ligamentum flavum, facet capsules, intervertebral disc annulus). As we age, degenerative changes occur in our spine causing narrowing of the central spinal canal area, and/or the area where the nerve roots exit the spinal canal (foramina). One of these degenerative changes is the formation of extra bony growths called osteophytes. Additionally, the large connective "band" (ligamentum flavum) which runs along the inside the spinal canal can become coarse and thickened also causing narrowing of the central canal space.