Lumbar spinal stenosis is present when the spinal cord becomes compressed in the spinal canal. This usually happens in older adults. The lower back or lumbar spine is made of a stack of 5 block-like bones called vertebrae. These bones surround and protect the spinal cord which runs down a tube-like canal in the center of the spine. They are separated by five oval cushions called discs. One or more discs may bulge into the spinal canal and cause lumbar stenosis.
If the discs become thin or worn degenerative disc disease is present. Extra calcium grows around the spinal joints and the edges of the spine resulting in calcium deposits or ‘bone spurs’. This calcium buildup is similar to that seen in the knuckles in people with osteoarthritis in their fingers. The calcium deposits may narrow the spinal canal, and be another cause a pinching or compressing of the spinal cord. Lumbar spinal stenosis causes the buttocks and thigh muscles to ache or feel weak with walking, sometimes extending into the lower legs. It is generally much better after a short period of rest. Often leaning forward or on a shopping cart is helpful.
It is not unusual for people with lumbar spinal stenosis to have very little back pain, but only experience pain in the upper legs and hips after walking or standing too long. Often there is concern about blocked arteries, but if poor blood circulation is to blame, usually the pain starts in the calves rather than the upper leg muscles with walking.
X-rays of the lumbar spine may suggest spinal stenosis is present, or show misalignment of the spine, but x-rays are only two dimensional pictures of the back, and in order to ‘look down the barrel’ and see the spinal canal in detail, 3D views are necessary. These views are shown by CT or MRI scans. A myelogram (a procedure when dye injected into the spinal canal) is sometimes is necessary.
Mild or moderate spinal stenosis symptoms may be managed by improving the muscular strength and endurance in the legs and remaining active. Steroid or cortisone injections (epidural injections) may provide temporary relief, but do not correct the situation. Sometimes a small spacer called an X-stop is inserted between the vertebrae. Generally surgery is reserved for leg and hip pain that is very limiting, and begins within 10-15 minutes of walking. One of the most successful types of surgery for lumbar stenosis is called a laminectomy. The best approach is the one that is individualized and provides the most relief, with the fewest side effects.