Discogenic Back Pain and Annular Tears

What it is

Between each pair of bones in your lower back sits a disc. Think of it as a small jelly doughnut: a soft center (the nucleus) wrapped in a tough outer ring (the annulus). The ring is made of many layers of fibers, like the rings of a tree, and it holds the center in place while you bend, twist, and lift.

An annular tear is a crack in that outer ring. It can come from a single lift or twist, but more often it is the result of years of ordinary loading on a disc that has slowly lost some of its water and spring. When the crack reaches the outer layers, where the ring has nerve endings, the disc itself becomes a source of pain. That is what "discogenic" means: pain from the disc.

This is different from a herniated disc. In a herniation, the soft center pushes out through the ring and presses on a nerve, which is what causes sciatica. In an annular tear, the center stays mostly inside. The problem is the ring itself, and the pain is mainly in the back rather than the leg.

Discogenic pain is one of the most common causes of long-lasting low back pain. Depending on the study, it accounts for roughly one in four to two in five cases.

What it feels like

People with a painful disc describe a very consistent pattern, and I listen for it:

• A deep, central ache. The pain sits in the middle of the low back, or just to one side, and feels deep rather than on the surface. Many people cannot put a finger on one spot; they press the flat of their hand over the whole area instead.
• Sitting is the enemy. Sitting puts more pressure inside the disc than standing does, especially slumped sitting. A car ride, a movie, or a long meeting brings the ache on, and standing up afterward is slow and stiff. Most people with disc pain would rather stand or walk than sit.
• Bending forward and lifting hurt. Leaning over the sink, picking something up off the floor, putting on shoes, and carrying groceries all load the front of the disc and open the crack at the back. Coughing and sneezing can send a jolt through it.
• Mornings are worse. Discs soak up water overnight while you lie down, so they are at their fullest and stiffest first thing in the morning. The first bend of the day is often the hardest.
• Flares. The pain is not steady. It runs in flares that last days to a few weeks, set off by a long drive, a lifting day, or sometimes nothing you can name, and then settles back down to a lower level or goes away. Between flares you may feel almost normal.
• Standing and walking usually help. Gentle movement, walking, and lying down tend to ease it. This is the reverse of facet joint pain, which is usually worse with standing and arching back and better with sitting.

Why a torn disc can cause leg pain without a herniation

This surprises many people, so I explain it carefully. The soft center of the disc is normally sealed off from the rest of the body. When a tear lets a little of that material leak toward the back of the ring, the body treats it as something that does not belong there and sets up a strong local inflammation. The nerve root that runs down to your leg passes right behind the disc, so that inflammation can irritate it.

The result is leg pain, tingling, or a burning sensation that feels like sciatica, even though nothing is pressing on the nerve. Some doctors call this a chemical radiculitis. On an MRI, there is no herniation squeezing the nerve; there is just an irritated disc next to an irritated nerve.

The important word is temporary. Because the leg symptoms come from inflammation rather than pressure, they usually fade over a few weeks as the inflammation calms, often faster than the back ache itself. They also tend to be milder and less sharply defined than true sciatica: more of a vague ache or tingle down the thigh than a hot wire from the buttock to the foot, and without weakness. When leg pain is severe, follows one strip of skin, comes with numbness or weakness, or is still there after six weeks, I think about a true lumbar radiculopathy instead and look harder for a herniation or narrowing.

How we diagnose it

Your story does most of the work. The pattern above, sitting intolerance, pain with bending and lifting, a deep central ache, and flares, points strongly at the disc. On exam, I check how you move, which positions reproduce your pain, and whether your nerves are working normally.

An MRI shows what the disc looks like. A painful disc is often darker than its neighbors, because it has lost water, and sometimes there is a small bright spot at the back of the ring where the tear is, which radiologists call a high-intensity zone. I use the MRI to confirm the story and to rule out a herniation or other cause, but I am careful not to over-read it: tears and worn discs are very common on scans of people who have no pain at all. The picture has to match your symptoms.

A test called discography, which injects the disc under X-ray to see whether it reproduces your exact pain, is rarely needed. I use it only when the answer would change a surgical decision.

How we treat it

Almost everyone with discogenic pain gets better without surgery, and I want to be honest about the timeline: the tear itself heals slowly, because the disc has almost no blood supply, but the pain settles much sooner than that as the inflammation quiets. Most flares ease within six to twelve weeks. The treatment is designed to get you through a flare and to make the next one less likely.

• Keep moving. Bed rest makes disc pain worse, not better. Walking is the best medicine there is for a sore disc.
• Manage sitting during a flare. Break up sitting every twenty to thirty minutes. Sit tall with a small rolled towel or lumbar roll behind the small of your back. In the car, adjust the seat so your knees are not above your hips.
• Protect the first hour of the morning. Avoid heavy bending and lifting right after you get up.
• An extension-based program. Exercises that gently arch the back take pressure off the back of the disc and often "centralize" the pain, pulling it out of the leg and into the back, which is a good sign. I have written out a starting program in my extension-based home program for low back pain. Bring it to your therapist.
• Core strength for the long run. Once a flare settles, the muscles of the trunk take over some of the load that the disc has been carrying. My core program for low back pain is the maintenance plan.
• Medicines. An anti-inflammatory for a limited time, with food, if your stomach and kidneys allow it. Heat for the muscle spasm that comes with a flare.
• Injections. An epidural steroid injection can calm the inflammation around the nerve and is most useful when leg symptoms are the bigger problem. It helps the back ache itself less reliably.

Surgery has a small role here. Operations for back pain from a disc alone, without a nerve being pinched, give far less predictable results than operations for leg pain from a pinched nerve. Fusion is reserved for only when it is truly needed, and a tear in a disc is almost never that reason: a fused level stops moving and shifts extra load onto its neighbors, which can speed their wear. I bring surgery into the conversation only when a well-defined problem has not responded to a full, patient trial of everything above.

The science: for the curious

Only the outer third of the annulus has nerve endings, which is why a small tear deep inside the disc is painless and a tear that reaches the outer layers is not. The soft center contains chemicals that, when they leak into the outer ring or beyond it, trigger inflammation and make those nerve endings more sensitive. Those same chemicals, reaching the nerve root behind the disc, are the explanation for leg pain without a herniation, and the reason that pain tends to fade as the chemicals are cleared.

The disc heals poorly because almost no blood reaches it; nutrition seeps in from the bone above and below. A tear often closes with scar rather than new disc tissue, and the disc may stay a little darker on MRI for good. That does not mean it will keep hurting. Annular tears show up on the scans of about one in five people in their twenties who have no back pain at all, and about one in three pain-free people in their eighties. The scan describes wear; your symptoms describe the problem. I treat the problem.

When to call

Call if the pain is spreading below the knee and not settling, if you notice new numbness or weakness in the leg or foot, if the leg symptoms are still present after six weeks of a proper program, if you have a fever with back pain, or if you are losing weight without trying. New trouble controlling your bladder or bowels, or numbness in the groin and inner thighs, is an emergency: go to the nearest emergency room or call 911.

Learn more

OrthoInfo, Low Back Pain: orthoinfo.aaos.org (opens in a new tab)

OrthoInfo, Herniated Disk in the Lower Back: orthoinfo.aaos.org (opens in a new tab)

My guides to facet joint pain, the other common source of mechanical back pain, to lumbar radiculopathy, and to degenerative disc disease, and my extension-based home program for low back pain.

This handout is general education about a common condition and does not replace the personalized advice we discuss in clinic. If anything here does not match what we talked about, what we talked about wins: please ask me.