What is Lumbar Spinal Stenosis?
The narrowing is due to wear and tear of the facet joints and ligaments, which thicken and bulge into the spinal canal (Fig 1) causing nerve compression. In some patients, the compression is worsened further by a slipped vertebrae (degenerative spondylolisthesis), which can also cause back pain (Fig 2).
What are the symptoms?
The symptoms include pain, numbness, tingling and/or weakness in one or both legs, typically brought on by standing or walking. The symptoms tend to be improved by sitting, leaning forwards, stooping or crouching.
The leg pain gradually worsens over six to 18 months until it limits walking to less than 200 metres or standing less than ten minutes. Patients may find that their ability to tolerate the symptoms in a bent or sitting position, for example when cycling or leaning forwards on a shopping trolley, is much better than activities which require standing or walking upright. Some patients experience leg pain at night when lying flat on their back and are able to relieve the pain by sleeping on their side and pulling the knees up towards the chest.
What investigations are required?
Spinal stenosis is best diagnosed with a spinal Magnetic Resonance Imaging (MRI) scan which shows spinal structures in great detail (Fig 1).
What are the treatment options and prognosis?
Some patients with mild stenosis may remain stable with fluctuating, tolerable symptoms for several months. In most cases, however, the spinal stenosis tends to worsen over time with a gradual deterioration in the symptoms leading to reduced mobility and overall quality of life. Patients with advanced spinal stenosis seldom improve without surgical treatment, which provides the only long-term solution. The operation commonly performed for this condition is a Lumbar Decompression, which has a success rate of 80 – 90% in curing the leg pain and restoring mobility.