Aging Begins at 30

Squeezing the Spinal Cord

Two retired university professors and friends of mine have spinal stenosis, that is narrowing of the canal inside the spine that contains the spinal cord and its nerves. Spinal stenosis is usually found in people aged 60 and older and six times as often in men as in women. It was first described in 1955 and became more evident when CT scans of the spine began to be used.

I noticed they both leaned forward to ease their pain when they walked. Elmer told me, "Every time I walk 200 yards or more I get numbness - no it's really pain - in my buttocks, thighs, and legs. It's mainly on the left but sometimes it's both sides. It doesn't stop when I stop. I have to sit or lie down and, if it's really bad, I need to go into the fetal position before it goes away. I used to have chronic aching low back pain but this is different." I realized by his description he had pseudo claudication, an old term for what is now more commonly called spinal stenosis. The real claudication (named after the limping Roman Emperor Claudius), is leg pain that stops when you stop and is due to poor blood supply to the leg.

I know from experience that these patients can ride a stationary or mobile bicycle, they can walk behind a shopping cart or lawn mower, and up a hill or stairs, but going downwards really brings on the pain. The normally oval spinal canal enlarges slightly by bending forward and narrows with standing and leaning back. You can see it on a CT or an MRI scan of the spine when the oval is changed to a 3-lobed trefoil-leaf pattern of narrowing in the presence of spinal stenosis. This is usually enough for diagnosis, however one may have to add x-ray contrast dye to show obstruction to passage of the dye. Older people, because of arthritis, can have very deformed spinal canals without obstruction. Sometimes people have to be re-examined at 3-6 month intervals until the clinical impression is confirmed. The block is most often at belt level in the middle and lower lumbar spine.

There is not much to find on physical examination, but some leg nerves may show electrical evidence of degeneration. The pulses in the feet will be normal. If the pain was due to blocked blood vessels, the pulses would be gone.

Patients need to alter their lifestyle. They need to strengthen the long muscles of the back and eliminate their pelvic tilt. They may need aspirin or non-steroidal anti-inflammatory drugs like naproxen or sulindac. Steroid injections into the spipne joints or on to the covering of the cord can help too.

If palliative measures fail, the affected area of spinal canal can be surgically enlarged by cutting away the arches at the back of the spine (called laminectomy) and freeing up the nerve roots from scarring and bony pinching. This is a serious operation and is delayed as long as possible. About 80% of patients are much better and can walk 1-2 miles without discomfort after operation.

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See related Patient Topics Bones, Joints and Muscles or Spinal Stenosis.

See related Provider Topics or Bones, Joints and Muscles.

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