Procedures · Interventional pain

Epidural steroid injections

Anti-inflammatory medication placed into the space immediately around an irritated nerve, under live X-ray guidance, through a needle. No incision and nothing to recover from. For most people it is the first thing tried after physical therapy and medication, and for a great many of them it is the only thing needed — which is why it sits in front of almost every surgical pathway on this site.

Why you are here

Seven different problems, one injection

They do not feel alike and they are not the same diagnosis. What they have in common is an inflamed nerve inside a space a needle can reach.

Lumbar transforaminal epidural steroid injectionThe animation shows the lumbar transforaminal route, which is the commonest. 1:52.

What it does

It treats the inflammation, and it tells us where the problem is

Both halves matter, and the second is the one people are rarely told about.

What it does
Steroid placed against an inflamed nerve root settles the chemical irritation that is doing most of the hurting. Pain eases over a few days to a couple of weeks, and the window that opens is what makes physical therapy possible for people who could not tolerate it before.
What it does not do
It does not remove a disc fragment, widen a canal or change anything on your MRI. Nothing about it makes the anatomy different. Where the compression is mechanical and severe, an injection buys time rather than a cure — and it is honest to say so beforehand.
What it tells us
A targeted injection at one level that takes the leg pain away is strong evidence that that level is the one responsible. Where an MRI shows changes at three levels and the symptoms could belong to any of them, this is often the cleanest way to find out — and it is why the injection sits in front of surgery rather than being an alternative to it.
How many
Usually up to about three in a year, spaced out, and only repeated if the previous one genuinely helped. Repeating an injection that did nothing is not a plan; it is a reason to re-examine the diagnosis.
Three routes

The needle reaches the same space three different ways

Which one is used depends on where the inflammation is, on what has been done to your spine before, and on what the live X-ray shows on the day.

Transforaminal
Through the tunnel the nerve root leaves by, so the medication lands directly on that one root. The most precise of the three, and the one with the most diagnostic value, because it implicates a single level.
Interlaminar
Between the bony plates at the back, into the epidural space itself. Spreads more widely than a transforaminal injection, which is what you want when the crowding involves several roots rather than one.
Caudal
Through the natural opening at the very bottom of the sacrum, below the levels of interest. Useful when scarring from previous surgery makes the space above difficult to enter safely.
On the day

What to expect

Setting
Outpatient, under live X-ray
Anaesthetic
Local, often with light sedation
Time in the room
About 15–30 minutes
Home
The same day, with a driver
Back to work
Usually the next day
When it works
Days to about two weeks

These are general ranges from the interventional pain literature and from routine practice, not a guarantee for any individual case. Blood thinners have to be discussed before booking, and an injection is deferred if there is any active infection. If you develop a fever, worsening weakness, or new trouble controlling your bladder or bowels after an injection, that is not something to wait on — call the office, or go to the emergency department.

What happens after depends on the answer, not on the plan

A good and lasting response means the inflammation was the problem and it has been treated. A good but short response tells us the level is right and the compression is mechanical, which is the conversation about whether an operation is worth it. No response at all is also information: it sends the search somewhere else, most often to the facet joints, to the vertebral body itself, or to the sacroiliac joint — each of which has a different treatment and its own page here.