A discogram — more precisely, provocative discography — is a diagnostic test in which contrast dye is injected under pressure into one or more spinal discs while the patient stays awake and reports what they feel. It is not a treatment and not an imaging study in the ordinary sense: the point is whether pressurizing a particular disc reproduces the patient’s own familiar pain, and whether neighboring discs do not.
Why the test exists
A discogram is almost never ordered to find out if a disc looks bad — an MRI already answers that. Degenerated discs are extremely common in people with no back pain at all. A systematic review of imaging in 3,110 asymptomatic individuals found disc degeneration in 37% of 20-year-olds and 96% of 80-year-olds, with annular fissures in 19% to 29% depending on age.1 Scan enough pain-free people and you will find plenty of ugly discs.
So imaging alone cannot tell you which disc, if any, is generating a given person’s pain. Provocative discography adds a physiologic step: stimulate the disc directly and see whether the patient recognizes the sensation as their own pain. In the literature this is called concordant pain. A disc that hurts in an unfamiliar way is not concordant, and under most protocols is not counted as positive.
How the procedure is done
The patient lies prone and the skin and deeper tissues are numbed. Under live fluoroscopic guidance, a thin needle is advanced posterolaterally into the center of the target disc — the nucleus pulposus — while a second needle is placed in at least one adjacent disc to serve as a control. Contrast is then injected slowly, often with a manometer measuring pressure inside the disc.
Three things are recorded at each level:
- Pain intensity — usually on a 0–10 scale.
- Concordance — whether the pain is the patient’s usual pain, a different pain, or no pain at all.
- Pressure and volume — how much pressure above opening pressure provoked the response, and how much contrast the disc accepted.
The patient must be awake and able to answer questions; sedation deep enough to blunt reporting destroys the only thing the test measures. A CT scan afterward maps annular fissures more precisely than fluoroscopy alone.
Everything described on this page concerns lumbar discography, which is where all of the evidence cited below comes from. Cervical and thoracic discography are also performed, but none of these studies address them.
Recovery
Recovery is short. Expect soreness at the needle sites and a flare of the usual back pain for a day or two, and arrange a ride home. The thing to watch for afterward is infection: new fever, or back pain that escalates instead of settling, should be reported promptly rather than waited out. That risk is quantified further down.
What counts as a positive result
There is no single universally accepted definition, which is part of the problem. Stricter pressure-controlled protocols require all of the following: pain at or above a set threshold (commonly 6/10 or 7/10), described by the patient as familiar, provoked at low pressure — for example, at or below 50 psi above opening pressure — with a limited injected volume, and at least one adjacent control disc that is not painful.2
The control disc is not a formality. Without a negative neighbor, a painful injection cannot distinguish a specific pain generator from a patient who hurts whenever anything in the spine is pressurized.
The controversy, stated plainly
Provocative discography has been contested for three decades, and the criticism is substantive. The most influential body of work comes from Eugene Carragee and colleagues at Stanford, who ran controlled experiments injecting discs in people who were not there for back pain.
In one small but pointed study, eight patients with no history of low back pain — who had undergone posterior iliac crest bone graft harvesting for unrelated surgery — underwent lumbar discography. Half met the usual criteria for a positive discogram, reporting pain they judged similar or identical to their graft-site discomfort.3 The sample was tiny; the implication was not. Patients may be unable to reliably separate spinal from non-spinal sources of pain during the test.
A second study looked at 20 asymptomatic volunteers who had done well after a single-level discectomy. Forty percent had positive injections of the previously operated disc. Among symptomatic post-discectomy patients with normal psychometric testing the rate was 43% — a difference that did not reach statistical significance, though that comparison group numbered only seven people, so on its own it settles little. The clearer signal in the same study was that patients with abnormal psychometric profiles had markedly higher positive rates than either group.4
A third tested whether restricting positives to low-pressure injections would eliminate false positives, as had been argued. Among 69 volunteers without clinically significant low back pain, 25% had at least one low-pressure positive disc — essentially the 27% rate seen in patients being worked up for chronic low back pain. Positive injections tracked with annular disruption, chronic pain elsewhere, and abnormal psychometric findings.5
Then came the outcome question. Thirty-two patients with a positive single-level low-pressure discogram went to fusion and were compared against a matched cohort with unstable spondylolisthesis — a lesion nobody disputes. By a highly effective success threshold, 72% of the spondylolisthesis group succeeded versus 27% of the presumed discogenic pain group; adjusted for surgical morbidity and dropout, the best-case positive predictive value of discography worked out to 50% to 60%.6
That is a thin margin on which to build a fusion decision. Separate work points the same way, with caveats: in a retrospective cohort where the decision to fuse had already been made on other grounds, the discographic status of the discs adjacent to the fusion had no effect on clinical outcome, and an accompanying systematic review found that no commonly used prognostic test for lumbar fusion has adequate accuracy.7
The case for the test, honestly stated
The defense is not that the critics have their numbers wrong. It is that false-positive rates depend heavily on technique and on who is being tested. Under strict pressure-controlled, manometric criteria, the test discriminates better in at least some populations. In one prospective study, 58.2% of discs in asymptomatic volunteers had Grade 3 annular tears — visibly abnormal discs — and yet every one met negative response criteria when strict pressure and intensity thresholds were applied.2 That is exactly the discrimination the test is supposed to provide.
The counterweight is the low-pressure study above: tightening the pressure threshold did not eliminate false positives in volunteers who had chronic pain elsewhere or abnormal psychometric findings.5 Both findings can be true at once. Strict criteria appear to help most in people who are otherwise well, and least in the patients most likely to be sent for the test in the first place.
A 2013 systematic review of the accuracy literature graded the overall quality of evidence as fair, and concluded discography may be useful when performed to formal International Association for the Study of Pain criteria.8 That review appeared in Pain Physician, the journal of the American Society of Interventional Pain Physicians, and its first author founded both the society and the journal — worth knowing when weighing it against the Stanford work. Fair is not strong. It is also not nothing.
Technique and patient selection therefore carry almost all of the diagnostic weight. A discogram done without manometry, without a control disc, or on a patient with widespread pain generates a number that looks like data and is not.
The risk that changed the conversation
Puncturing a disc is not a neutral act. In a prospective matched-cohort study, 75 subjects underwent discography at L3–S1 in 1997 and were compared 10 years later with matched controls given the same MRI protocol but no injections. Punctured discs progressed more on every measured parameter: degeneration in 35% of discography discs versus 14% of controls, and 55 new disc herniations versus 22 — disproportionately on the side of the annular puncture.9
A follow-on analysis of the same cohorts tracked clinical events rather than images. Over 10 years there were 16 lumbar surgeries in the discography group versus 4 in controls, with more medical visits, more CT and MRI studies, more work loss, and more prolonged back pain episodes.10 These were people with no serious back pain problem when they enrolled.
Discitis — infection of the disc space — is rarer but more acute. A systematic review plus a series of 200 consecutive patients found an incidence of 0.25% without prophylactic antibiotics.7 Low, but not trivial for a purely diagnostic test.
Who is a reasonable candidate
A discogram makes sense in a narrow situation: persistent axial low back pain that has not responded to a real course of conservative care, imaging showing one or two plausible levels, other pain generators already ruled out, and a specific surgical or interventional decision waiting on the answer. Ordering it when the result would not change anything is a common misuse.
It is a poor choice when pain is widespread rather than focal, when facet joints or the sacroiliac joint have not been evaluated, when psychological distress is prominent and untreated, or when there is active infection, bleeding risk, or pregnancy. False positives cluster in exactly the patients who are hardest to sort out clinically.5
What happens with the result
A concordant single-level positive with negative control discs, in a well-selected patient, supports — but does not establish — that disc as the pain generator. It may lead to fusion, disc replacement, or a targeted intradiscal or epidural procedure. Where scarring and adhesions in the epidural space are contributing, epiduroplasty (epidural lysis of adhesions) is sometimes the more proportionate next step than fusion.
A negative discogram is often the more valuable outcome: it removes a level from surgical consideration and redirects the workup toward facet joints, the sacroiliac joint, or a central pain mechanism.
If you are in the St. Louis area
Padda Institute, Center for Interventional Pain Management performs fluoroscopically guided diagnostic procedures at 4477 Woodson Rd, Suite 100, St. Louis, MO 63134 and 12174 Natural Bridge Road, Bridgeton, MO 63044. For preparation instructions and scheduling, see the discogram procedure page or call (314) 481-5000.
Frequently asked questions
Is a discogram painful?
Yes, by design — the test only works if pressurizing the disc reproduces pain. Local anesthetic numbs the needle path, but the provocation itself is the measurement. If that is not acceptable to you, discuss alternatives such as diagnostic medial branch blocks, which work by relieving pain rather than provoking it.
Why can’t an MRI tell my doctor which disc hurts?
Because degenerative findings are nearly universal with age and correlate poorly with symptoms. An MRI shows structure, not nociception. See why your scan may not match your pain and what MRI, fluoroscopy, and ultrasound each actually measure.
What is internal disc disruption?
Annular fissures and internal breakdown in a disc whose external contour still looks acceptable — the classic case of real axial back pain with a reassuring MRI. It is the condition provocative discography was designed to identify, covered in our article on internal disc disruption with a normal MRI.
Does a positive discogram mean I need fusion surgery?
No. It is one input among several, and the published positive predictive value for surgical success is far from convincing. Reviews of the chronic low back pain literature also report that intensive exercise and cognitive behavioral programs produce results similar to fusion with fewer complications, so a positive result is a reason for a careful conversation, not an automatic operation.7 See the data on unnecessary back surgeries before committing to an operation.
Can a discogram damage my disc?
The 10-year matched-cohort evidence says puncture accelerates degeneration and raises the rate of new herniations and later surgery compared with unpunctured controls. That is the main reason the test should be reserved for cases where the answer changes the plan. If you have already had spine surgery and still hurt, see why leg pain persists after back surgery and failed back surgery syndrome.
What should I ask before agreeing to a discogram?
Three things: what decision hangs on the result, whether a control disc and manometry will be used, and what happens if the test is negative. If no answer changes the plan, the test is not indicated. See what to expect at a first pain appointment and choosing between an orthopedic surgeon, neurosurgeon, or pain physician.
Sources
- Brinjikji W, Luetmer PH, Comstock B, et al. Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. AJNR Am J Neuroradiol. 2015;36(4):811-816. PMID 25430861
- Derby R, Kim BJ, Lee SH, Chen Y, Seo KS, Aprill C. Comparison of discographic findings in asymptomatic subject discs and the negative discs of chronic LBP patients: can discography distinguish asymptomatic discs among morphologically abnormal discs? Spine J. 2005;5(4):389-394. PMID 15996608
- Carragee EJ, Tanner CM, Yang B, Brito JL, Truong T. False-positive findings on lumbar discography. Reliability of subjective concordance assessment during provocative disc injection. Spine (Phila Pa 1976). 1999;24(23):2542-2547. PMID 10626318
- Carragee EJ, Chen Y, Tanner CM, et al. Provocative discography in patients after limited lumbar discectomy: a controlled, randomized study of pain response in symptomatic and asymptomatic subjects. Spine (Phila Pa 1976). 2000;25(23):3065-3071. PMID 11145818
- Carragee EJ, Alamin TF, Carragee JM. Low-pressure positive discography in subjects asymptomatic of significant low back pain illness. Spine (Phila Pa 1976). 2006;31(5):505-509. PMID 16508542
- Carragee EJ, Lincoln T, Parmar VS, Alamin T. A gold standard evaluation of the “discogenic pain” diagnosis as determined by provocative discography. Spine (Phila Pa 1976). 2006;31(18):2115-2123. PMID 16915099
- Willems P. Decision making in surgical treatment of chronic low back pain: the performance of prognostic tests to select patients for lumbar spinal fusion. Acta Orthop Suppl. 2013;84(349):1-35. PMID 23427903
- Manchikanti L, Benyamin RM, Singh V, et al. An update of the systematic appraisal of the accuracy and utility of lumbar discography in chronic low back pain. Pain Physician. 2013;16(2 Suppl):SE55-SE95. PMID 23615887
- Carragee EJ, Don AS, Hurwitz EL, Cuellar JM, Carrino JA, Herzog R. 2009 ISSLS Prize Winner: Does discography cause accelerated progression of degeneration changes in the lumbar disc: a ten-year matched cohort study. Spine (Phila Pa 1976). 2009;34(21):2338-2345. PMID 19755936
- Cuellar JM, Stauff MP, Herzog RJ, Carrino JA, Baker GA, Carragee EJ. Does provocative discography cause clinically important injury to the lumbar intervertebral disc? A 10-year matched cohort study. Spine J. 2016;16(3):273-280. PMID 26133255
Dr. Gurpreet Singh Padda, MD, MBA, MHP
