Sciatica or referred pain · St. Louis
Not everything that runs down a leg is sciatica.
“Sciatica” has become the word people use for any pain that travels below the buttock. Several different problems produce that pattern, and they respond to completely different treatments. Telling them apart takes a physical examination, not a guess.
What is sciatica, really?
Sciatica describes pain along the path of the sciatic nerve. It comes from irritation or compression of a lumbar nerve root — most often L5 or S1. It is a symptom of radiculopathy (a pinched or irritated nerve root), not a diagnosis in itself. The correct clinical question is never “is this sciatica?” but “which structure is producing leg pain, and at what level?”
That distinction is not nitpicking. True radicular pain gets better with treatment aimed at a nerve root. Facet or sacroiliac pain referred into the same leg gets worse under that treatment, or simply does not respond. The patient is then told their sciatica is stubborn, when in fact they never had it.
What else sends pain down the leg besides sciatica?
TRUE RADICULAR PAIN
A nerve root. The pain follows a set line you could draw with a finger, and it usually goes below the knee. It commonly comes with numbness, tingling or weakness in a matching pattern. Coughing or sneezing may shoot it. A straight leg raise brings it on.
This is the one that responds to an epidural steroid injection at the right level. It is also the one where progressive weakness changes the urgency entirely. Radiculopathy in full.
FACET REFERRAL
The facet joints refer pain into the buttock and the back of the thigh, and it characteristically stops above the knee. There is no true numbness and no weakness, because no nerve root is involved. It is worse leaning back (extension) and better bending forward (flexion). That is the reverse of the classic disc pattern.
It is often mislabeled as sciatica for years. Facet syndrome.
SACROILIAC JOINT REFERRAL
The sacroiliac joint refers pain into the buttock, the groin and sometimes down the back of the leg. It can go below the knee, which is what makes it convincing. The giveaways are pain centered below the belt line and a worst moment rolling over in bed. Another is pain brought on by provocation testing rather than by a straight leg raise.
This is the single most commonly missed cause of “failed sciatica treatment” we see. The SI joint.
NEUROGENIC CLAUDICATION
Narrowing of the canal produces leg pain and heaviness that come on with walking. They ease when you sit or lean forward. The tell is that it depends on position, not effort. That is why leaning on a cart buys you more distance than willpower does.
How can you tell if your pain is from sciatica?
- Where does it stop? Above the knee moves the odds toward facet or sacroiliac referral. Below the knee, in a line, moves them toward a nerve root.
- What makes it worse? Flexion (bending forward) and sitting suggest disc and root. Extension (leaning back) and standing suggest facet or canal. Rolling over and loading one leg suggest the sacroiliac joint.
- Is there a neurological deficit? Real numbness in a dermatome (the strip of skin one root supplies), a weak toe extensor, a lost reflex. A deficit means a root, and it changes the plan.
- Provocation testing. A cluster of sacroiliac provocation maneuvers, the straight leg raise and its crossed version, and a proper hip examination. That last one matters because a worn hip refers pain into the groin and thigh. It is regularly treated as a spine problem for a year.
- Then, where it still matters, a diagnostic block to confirm rather than infer.
Why the leg is the part that frightens people
Back pain is familiar. Leg symptoms are not, and numbness in particular feels permanent in a way a sore back does not. That fear is reasonable. It is also the reason this problem gets over-treated in one direction and under-examined in the other. People are moved quickly toward imaging and a surgical opinion. They are moved slowly, or never, toward the tests that would say which structure is responsible.
There is a second reason the leg matters. Lasting nerve root irritation drives central sensitization (the nervous system turning up its pain volume) faster than back pain alone does. So the window in which this is a simple mechanical problem is shorter. After a few months the leg can keep reporting pain after the compression has resolved. That is how a person ends up with a clean scan after surgery and an unchanged symptom.
Why does the same MRI finding hurt one person and not another?
Nerve tissue is metabolically expensive, and it is unusually sensitive to the state of its blood supply. Chronic hyperinsulinemia (long-term high insulin) and the low-grade inflammation that comes with it impair blood flow in the tiny vessels of the nerve root and its sheath. That lowers the point at which mechanical contact starts to cause symptoms, and it slows recovery once it does. In practice, a root that is mildly compressed in a metabolically healthy person is often silent. The same degree of contact in an inflamed system produces months of leg pain.
This is also why the same MRI can be read as trivial by one clinician and damning by another. The image is identical. The tissue it describes is not.
Questions people ask
What can be mistaken for sciatica?
Facet joint referral, sacroiliac joint referral, hip osteoarthritis, greater trochanteric pain syndrome, piriformis-related sciatic irritation, neurogenic claudication from stenosis, and occasionally vascular claudication, which is a different specialty entirely. That list is why the examination matters more than the label.
For telling a hip problem from a back problem, read hip pain or back pain.
Should you walk if you have sciatica?
Usually yes, within tolerance. Long rest makes it worse rather than better. The exception is progressive weakness or any of the red-flag findings. Then the instruction is to be seen rather than to keep walking.
Is sciatica curable?
Most acute radicular episodes settle substantially over weeks to a few months without surgery. The ones that do not are the ones worth investigating properly, and “curable” is the wrong frame for them — the useful question is which structure is responsible, and what is the most durable thing that can be done about it.
What vitamin stops sciatica?
None, and we are not going to pretend otherwise. B vitamins have a role in genuine deficiency states. Correcting a documented deficiency is worth doing on its own merits. There is no supplement that decompresses a nerve root.
Do I need an MRI first?
Not necessarily. If there is no deficit and no red flag, the exam decides whether imaging would change anything. Ordering a scan before knowing what you would do with the result is how people end up treated for an incidental finding (something on the scan that is not causing the pain).
For what an incidental finding on a scan does and does not mean, read what your MRI actually showed.
Can sciatica cause referred pain?
Not in the strict sense. Sciatica and referred pain are two different things. Sciatica is pain from an irritated lumbar nerve root, most often L5 or S1. It follows a line down the leg, usually below the knee. Referred pain comes from a joint, such as a facet joint or the sacroiliac joint. It spreads into the buttock and thigh with no nerve root involved. Both reach the leg, which is why they get confused.
What does referred pain in the leg feel like?
Facet referral settles in the buttock and the back of the thigh and usually stops above the knee. There is no true numbness and no weakness, and it is worse when you lean back. Sacroiliac referral centers below the belt line and can reach below the knee. It is at its worst when you roll over in bed.
How do you get rid of referred leg pain?
By treating the structure that is actually producing it. Referred pain from a facet or sacroiliac joint does not respond to treatment aimed at a nerve root, and it can get worse under it. The exam narrows down the source. Where it still matters, a diagnostic block confirms it before treatment is chosen. Guessing is how people end up told their sciatica is stubborn.
What is the difference between radiating and referred pain?
Radiating, or radicular, pain comes from a nerve root. It runs in a line you could draw with a finger and usually goes below the knee. It often brings numbness, tingling or weakness, and a cough or sneeze can shoot it. Referred pain comes from a joint. It spreads into the buttock or thigh without true numbness or weakness.
What kind of doctor should I see for sciatica?
One who examines the leg before treating it, because a nerve root, a facet joint, the sacroiliac joint and the hip all send pain down the same leg. An interventional spine and pain physician maps the root level by exam, confirms the source with a targeted block, and treats a true root with a transforaminal epidural at the matching level. A surgeon joins the conversation when weakness is progressing or a confirmed compression has not settled, and that consultation is worth more when the level arrives already proven. The first visit here is built around that exam.
What is the best medicine for sciatica?
No pill reliably reaches an inflamed nerve root. Pregabalin, the drug most often handed out for it, did no better than placebo for leg pain at eight weeks or at one year in a randomized trial of 209 adults with sciatica, and it caused more dizziness (New England Journal of Medicine, 2017). An anti-inflammatory can take the edge off for a few days. The way to put medicine where the inflammation actually is, is a transforaminal epidural steroid injection at the level the exam points to, used as a window to keep you walking while the disc material resorbs.
Do I need a referral if my leg pain might be sciatica?
No. You can book directly; some insurance plans want a referral on file, so check yours. Come ready to trace where the leg pain runs with one finger, because that line narrows the cause fast. Which nerve a numb patch on the foot points to.
When the exam cannot settle whether leg pain is a true nerve problem, an EMG nerve test of the leg measures how the nerve is actually working.
Related reading
- Lumbar radiculopathy
- Sacroiliac joint pain
- Spinal stenosis
- Epidural steroid injection
- When back pain is an emergency
- Hamstring tendonitis
The piriformis label is applied far more often than the condition occurs.
Bring the leg symptoms, not just the back
Where it starts, where it stops, what makes it worse and whether anything is numb or weak. Those four answers do more to narrow this than any scan you have had.
12174 Natural Bridge Rd, Suite 301
St. Louis, MO 63044
At DePaul Hospital on Natural Bridge Road, inside the I-270 and I-70 interchange, on the west side of the airport.
Sources
- Guedes F et al. Nondiscogenic Sciatica: What Clinical Examination and Imaging Can Tell Us?. World neurosurgery, 2020. PubMed 31760186
- Troutner AM et al. The ambiguity of sciatica as a clinical diagnosis: A case series. Journal of the American Association of Nurse Practitioners, 2020. PubMed 31567779
- Valat JP et al. Sciatica. Best practice & research. Clinical rheumatology, 2010. PubMed 20227645
- Park JW et al. Deep gluteal syndrome as a cause of posterior hip pain and sciatica-like pain. The bone & joint journal, 2020. PubMed 32349600