I pictured a bulge in a tyre wall

THE 30-SECOND VERSION

About two thirds of herniated discs shrink away on their own, without surgery. And the worse ones shrink most reliably of all. It takes months, not days.

THE MYTH

A herniated disc is not a permanent thing

First, the words, because they mislead. Nothing slips. A disc is firmly attached top and bottom. What happens is that some of the soft material inside pushes out through a weak spot in the tough outer ring, the way jam comes out of the side of a doughnut when you squeeze it.

Now the number. Researchers pooled 31 studies covering 2,233 people whose herniated discs were managed without surgery, and scanned them again later. Around two thirds of those herniations had shrunk on their own. Not managed. Not operated on. Simply gone, or well on the way.

The body appears to treat the escaped material as something that does not belong there, and sets about clearing it away, much as it would clear a splinter. The fragment also dries out and loses volume over time. Between the two, it goes.

And here is the part that runs backwards

A separate review sorted herniations by how bad they looked and found something nobody would predict. A mild bulge shrank on its own only about 13 percent of the time. A moderate protrusion, around 41 percent. A full extrusion, 70 percent. And the worst kind of all, where a fragment has broken free entirely, shrank in 96 percent of cases.

Read that again, because I had to. The more alarming the picture on the scan, the better the odds it clears up by itself. The thinking is that material which has broken fully out is most exposed to the blood supply, and so gets cleared away fastest. A small bulge still tucked inside is left alone precisely because it is still tucked in.

What this does not mean

It does not mean quickly. Large herniations in these studies cleared somewhere between three and twenty-one months. That is a long stretch to be uncomfortable, and nobody should be told to simply wait it out alone.

It does not mean surgery is never right. Some people need it, and some need it urgently. If you have severe or worsening weakness in a leg, or any numbness between the legs or trouble controlling your bladder or bowel, that is an emergency and none of these averages apply to you.

And remember what we found in August. What a scan shows and what a person feels do not always match. Some people improve long before the picture does. So this is not a promise about your pain. It is a correction about your disc.

Where the week lands

On Monday we trained the back to hold steady. On Tuesday we found that discs swell overnight and the first hour costs more. On Wednesday the famous lifting rule did not survive inspection. Yesterday the biggest trigger turned out to be a wandering mind. And today, the thing I had pictured as a ruined tyre is in most cases a splinter the body is quietly working its way out. That is not a bad week’s reading.