Home / Conditions / Slipped disc
The soft centre of a spinal disc pushing out and pressing on a nerve. The pain is often worse in the leg or arm than in the back — and most slipped discs settle without an operation.
Between each pair of vertebrae sits a disc: a tough outer ring around a soft, gel-like centre. A slipped disc — more accurately a herniated or prolapsed disc — is when that centre pushes through a weak point in the ring. The disc itself does not slip anywhere; the name has simply stuck.
The ring has to tear before the centre can escape, which is why a herniation is often the next stage of an annular tear. What makes a herniated disc painful is usually not the disc but what it presses on: the nerve root leaving the spine at that level.
In the lower back, that nerve runs down the leg, and the result is sciatica. In the neck, it runs down the arm — cervical radiculopathy, sometimes called sciatica of the neck. There is more on the commonest lower back level under L4–L5 herniated disc.
On the left, the lower spine from the side: soft disc material has pushed out backwards and is pressing on a nerve root on its way down. On the right, the same problem from above — the tough outer ring, the soft centre, and the piece that has broken through towards the nerve.
What the picture cannot show is where you feel it. The nerve being pressed runs on down the leg, so the pain is often felt in the calf or foot rather than at the disc.
MRI reports use these words for different amounts of disc material beyond its normal edge. They sound like a scale of severity. They are not quite that.
| Bulge | Protrusion | Extrusion | |
|---|---|---|---|
| What it is | The disc spreads evenly beyond its edge, like a tyre under load | The centre pushes out in one spot, with a broad base | The centre breaks through, wider at its tip than its neck. A piece that has separated is called sequestrated |
| In people with no pain | Very common, more so with age | Common | Much less common |
| Presses on a nerve | Rarely on its own | Sometimes | More often |
| Shrinks on its own | Uncommonly | Sometimes | Most likely of the three |
Two things follow. A bulge on a scan is often not the cause of anything. And the larger, extruded herniations — the ones that look worst — are the ones the body most often reabsorbs. What matters is whether the level and side on the scan match your symptoms and your examination.
In the lower back:
In the neck:
Leg pain worse than back pain is one of the clearer signs a disc is pressing on a nerve. Back pain on its own, without anything running down a limb, has many other causes — see lower back pain.
Most slipped discs can be assessed in the ordinary course of things. These cannot:
The first three can mean cauda equina syndrome, where a large disc compresses the nerves serving the bladder, bowel and legs. It needs emergency surgery, and the outcome depends on how quickly it is treated.
Call us on +65 8849 0677. We will see you the same day and arrange imaging if it is needed.
If we are closed, go to an emergency department — we are shut on Sundays and after 1pm on Saturdays. For the first three symptoms, go straight to an emergency department whether we are open or not.
Call +65 8849 0677An MRI is not always needed straight away. Without warning signs, most people are treated for the first several weeks on the basis of the examination. A scan becomes the question when symptoms are not settling, or when an injection or surgery is being considered.
Most people improve without an operation, usually within six to twelve weeks. Treatment is stepped, and most people never go past the first two tiers.
Bed rest slows recovery; walking and normal activity within comfort help it. Anti-inflammatories ease the inflammation around the nerve, and medicines aimed at nerve pain help the leg or arm symptoms. Heavy lifting and repeated deep bending are best avoided early on.
Once the worst has settled: movement that centralises the pain, trunk strengthening, and a graded return to lifting and sport.
A steroid injection placed around the affected nerve root can calm the inflammation enough for the leg or arm pain to ease while the disc settles. Relief varies and is often temporary, but it can be enough. Dr Tung performs CT-guided nerve root blocks with radiologists, and cervical epidural injections.
Considered for weakness that is significant or getting worse, for cauda equina syndrome, or for leg or arm pain that has not settled after a proper course of treatment — usually at least six weeks.
Surgery brings leg pain down faster. A year or two on, many people treated without it are doing similarly well, so where there is no weakness the choice is often about how long you are willing to wait.
For a slipped disc, either is appropriate. Both spine surgeons treat it, from injections to discectomy; they simply come at it from different training.
Leg or arm pain, numbness and weakness, and how badly the root is compressed.
A neurosurgeon trains on the nervous system first. Dr Mathew Tung performs discectomy using keyhole microsurgery, CT-guided nerve root blocks, and cervical and lumbar disc replacement.
The disc itself, the load on it, and the spine around it.
An orthopaedic spine surgeon trains on the musculoskeletal system first. Dr Lim Heng Hing treats slipped discs with endoscopic spine surgery, and uses intradiscal therapy for chronic disc pain.
You do not need to pick correctly. Either is a sound first appointment, and having both surgeons in one clinic means the answer is not shaped by whichever one you happened to book.
More on how the two differ: neuro spine and orthopaedic spine surgery.
Yes. Slipped disc, herniated disc and prolapsed disc all describe the same thing. The disc does not actually slip; its soft centre pushes out through the outer ring.
Often, yes. The body can reabsorb herniated disc material over weeks to months, and larger extruded pieces are the most likely to shrink. Most people improve without surgery.
Not necessarily. Disc bulges are common in people with no pain at all, and more so with age. Back pain without anything running down a leg often has another source, which the examination helps to find.
Only briefly, if at all. Staying as active as the pain allows, and walking in particular, is linked with faster recovery than bed rest.
Most people do not. Surgery is for weakness that is significant or getting worse, for cauda equina syndrome, or for pain that has not settled after a proper course of treatment.
No. Bring any MRI reports and images, and note where the pain goes — which toes or fingers — and whether anything feels weak.
Annular tear · Sciatica · Lower back pain · Spinal stenosis · Cervical radiculopathy · Sciatica of the neck · Foot drop · L4–L5 herniated disc
If you have an MRI already, bring the images as well as the report. The level on the scan has to match the level in your leg or arm.
