spinal cord compression
Meaning of spinal cord compression: Timing matters more than the size of the squeeze, since what a person can still do when treatment starts largely predicts what remains.
Definition of spinal cord compression
Spinal cord compression is pressure on the spinal cord from something taking up space inside the bony canal that houses it: a tumor, a collapsed vertebra, a bulging disc, a collection of blood or pus, or overgrown bone. The squeezed cord stops carrying signals properly, so weakness, numbness and loss of bladder or bowel control develop below the affected level.
What causes it?
| Cause | How the pressure arises |
|---|---|
| Cancer spread to bone | A deposit grows into the canal, or a weakened vertebra collapses into it |
| Injury | A fracture drives bone fragments inward |
| Disc herniation | The soft center of a disc bulges backward |
| Infection | An abscess collects in the space around the cord |
| Degenerative narrowing | Thickened ligament and bony spurs close the canal slowly |
| Bleeding | Blood gathers quickly, often where clotting is already impaired |
Speed of onset follows the cause. A fracture or a bleed compresses within minutes, a tumor over days or weeks, degenerative narrowing over years. A cord squeezed slowly adapts and tolerates remarkable distortion, which is why an alarming scan sometimes accompanies mild symptoms while sudden compression of the same degree causes complete loss of function.
What does it do?
Everything below the compressed level is affected, because signals in both directions pass through that point. Back pain usually comes first and often precedes anything else by weeks, worse lying flat or on coughing. Then weakness in the legs, a heavy or clumsy walk, and a band of numbness at the level itself. Bladder and bowel control fail late in most cases, which is why their loss is read as an ominous sign rather than an early one. Paralysis below the level is the end point if the pressure continues.
How does it differ from cauda equina syndrome?
The cord itself ends near the first or second lumbar vertebra, and below that the canal holds a bundle of nerve roots rather than cord. Pressure there gives a different pattern: numbness across the area that would contact a saddle, loss of bladder sensation, and weakness following individual root territories rather than everything below one line. Both are urgent, but the anatomy differs and so does the examination.
Why does timing matter so much?
Nerve tissue tolerates pressure poorly. Compression squeezes the small vessels feeding the cord as well as the cord itself, and the swelling that follows raises the pressure further. Function lost for any length of time frequently does not return once the pressure is relieved, while function still present when treatment begins is usually kept. Walking ability at the point of treatment is the strongest single predictor of walking ability afterward. A compression fracture narrowing the canal can also shift further, so the situation is rarely static.
Also known as
Used in a sentence
Urgent imaging was arranged for suspected spinal cord compression at the thoracic level.
Good to know
Loss of bladder and bowel control is usually a late feature rather than an early one, and the degree of function present when treatment starts is the strongest predictor of what is retained.
Word origin
Where “spinal cord compression” comes from
Spinal comes from the Latin spina, meaning a thorn and then the backbone; compression from comprimere, to press together.