Spinal stenosis is a narrowing of the spinal canal.
The spinal canal contains the nerves that leave the spinal cord. A combination of arthritis in the spine or bulging (herniation) of the discs or (in rarer cases) spondylolisthesis (where a vertebra slips forward or backward) or spinal tumours can cause this narrowing. Sometimes spinal decompression is performed to release nerves trapped by this narrowing.
Initially your consultant may recommend anti-inflammatory medication for pain. If you have pain down your leg that is caused by pressure on one of the nerves in your lower back (sciatica), your surgeon may recommend a steroid injection in your spine.