Spine: at 50, 80% of people with no pain have a degenerate disc

What MRI finds in people who hurt nowhere

This is where any discussion about backs has to start. The systematic review by Brinjikji (AJNR, 2015) pooled 33 studies and 3,110 people with no pain at all, then modelled the prevalence of each finding by decade.

At 50, four in five people who hurt nowhere have a degenerate disc on their MRI. The authors conclude that these images are likely part of normal aging. An MRI report listing five abnormalities therefore does not say where the pain comes from; it describes a spine of the patient’s age. The authors publish no confidence intervals around these prevalences, and we do not invent any.

Fusion or decompression alone: the argument has been settled

In 2016 two trials published on the same day in the same journal contradicted each other. Ghogawala (NEJM, 2016), 66 patients, found an advantage for fusion on the SF-36 physical score at 2 years: 15.2 against 9.5, difference 5.7 with a confidence interval from 0.1 to 11.3. The lower bound grazes zero, and the secondary outcome, the Oswestry Disability Index, was not significant. The same day Forsth (NEJM, 2016), 247 patients, found no difference at all: Oswestry 27 against 24, p equal to 0.24, and a six-minute walk test of 397 metres against 405.

What followed separated the two.

Four later meta-analyses converge. Gadjradj (Eur Spine J, 2023) speaks of high-quality evidence of no difference on the Oswestry index at 2 years, with a mean difference of -0.31 and an interval from -3.81 to 3.19. The one result favouring fusion, Pranata (Int J Spine Surg, 2022) across 3,993 patients, gives 4.04 Oswestry points, below the usual threshold of clinical relevance.

The single finding of Ghogawala’s that has not been replicated is his 34% reoperation rate after decompression alone. NORDSTEN-DS finds 12.5% at 2 years and 16% at 5 years, Forsth 21% to 22%.

Sciatica, and what delay actually changes

Two trials answer two different questions, and they are constantly conflated.

Peul (NEJM, 2007) randomised 283 patients with severe sciatica of 6 to 12 weeks between early surgery and prolonged conservative care. Early surgery relieves pain faster, with a hazard ratio for perceived recovery of 1.97 and an interval from 1.72 to 2.22. But at one year, perceived recovery reaches 95% in both groups. At two years there is no difference in disability, and 44% of the conservative group had eventually been operated on.

Bailey (NEJM, 2020) asked it differently, in 128 patients whose sciatica had already lasted 4 to 12 months. There the gap is clear and lasting: leg pain score at 6 months of 2.8 against 5.2, adjusted mean difference 2.4 with an interval from 1.4 to 3.4.

The reading that follows from those two trials is simple. In the first weeks, operating speeds things up without changing the result at one year. Beyond four months of persistent sciatica, the gap becomes real. It is the duration of symptoms, not the look of the image, that moves the benefit-risk balance.

The problem with the SPORT trial, and why it is cited badly

SPORT is the most cited trial on back surgery, and the most badly cited. In the disc herniation arm (JAMA, 2006), 50% of patients assigned to surgery were operated on within three months, and 30% of those assigned to conservative care were too. The authors themselves write that no conclusion of superiority or equivalence is warranted from the intention-to-treat analysis.

In lumbar stenosis at 8 years (Spine, 2015), 70% of patients randomised to surgery and 52% of those randomised to conservative care had been operated on. The early benefit of surgery, present up to 4 years, is no longer found between the sixth and the eighth year. Follow-up at 8 years was 55%, and those lost to follow-up were older and sicker in both arms.

What SPORT does establish solidly is the size of the improvement after surgery in the as-treated analysis: 15.0 points of bodily pain at 4 years for disc herniation, with an interval from 11.8 to 18.1. What it does not establish is a clean comparison between operating and not operating.

Reoperation, and what the word covers

The often quoted range of 10% to 40% for failed back surgery syndrome has no primary source we have been able to trace. The best available data, across 102,047 patients, gives 5.4% at 6 months and 8.4% at 12 months. The gap between the two comes down to definitions, and it is wide enough that the range cannot be used.

What the studies do not allow us to claim

That 90% of sciatica resolves in six weeks without surgery: we found no primary source. The verified anchors are Peul’s, 95% perceived recovery at one year in both arms, and 20% unsatisfactory outcomes at two years. It is a less tidy story.

The 48-hour golden window in cauda equina syndrome rests on a meta-analysis from 2000 covering 322 patients from retrospective studies. It shows a difference between under 48 hours and over 48 hours, but none between under 24 hours and 24 to 48 hours. The most recent meta-analysis, across 987 patients (Spine J, 2026), concludes that evidence on the effect of surgical timing is heterogeneous and inconclusive, and finds 32.6% persistent bladder dysfunction in the long term. Cauda equina syndrome remains an absolute emergency; the numerical threshold is less solid than it is said to be.

Finally, the often quoted ratio between American and European fusion rates rests on no recent, methodologically homogeneous international comparison. We do not cite it.

In practice, if this concerns you

Three questions structure the discussion. How long has the leg pain lasted, since that is what moves the benefit-risk balance most. Is the proposed procedure a decompression alone or a fusion, and on what argument is the fusion being added. And does the clinical picture match the image, since a finding present in 80% of people your age with no pain cannot, on its own, be an indication.

Noria Health arranges a full spinal work-up near Brussels within 24 to 48 hours: neurological examination, gait assessment, MRI read with the clinical picture in hand, and a surgical opinion only where the examination justifies it. The report is issued within 24 hours, follow-up is structured at D14, D30 and D90, and surgery is considered only around day 10 if it is needed.

What Noria Health does not do: set a surgical indication on an MRI alone. A rapidly developing motor deficit, numbness in the saddle area or a recent change in bladder control are matters for the emergency services in your country, immediately, not for an appointment.

Further reading

• A spine MRI does not tell you the pain
• What waiting costs in orthopaedics
• Pain that waits

Sources

1. 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;36:811-816. https://pubmed.ncbi.nlm.nih.gov/25430861/
2. Ghogawala Z, Dziura J, Butler WE, et al. Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis. N Engl J Med, 2016;374:1424-1434. https://pubmed.ncbi.nlm.nih.gov/27074067/
3. Forsth P, Olafsson G, Carlsson T, et al. A randomized, controlled trial of fusion surgery for lumbar spinal stenosis. N Engl J Med, 2016;374:1413-1423. https://pubmed.ncbi.nlm.nih.gov/27074066/
4. Austevoll IM, Hermansen E, Fagerland MW, et al. Decompression with or without fusion in degenerative lumbar spondylolisthesis. N Engl J Med, 2021;385:526-538. https://pubmed.ncbi.nlm.nih.gov/34347953/
5. Kgomotso EL, Hellum C, Fagerland MW, et al. Decompression alone or with fusion for degenerative lumbar spondylolisthesis, five year follow-up of NORDSTEN-DS. BMJ, 2024;386:e079771. https://pubmed.ncbi.nlm.nih.gov/39111800/
6. Karlsson T, Forsth P, Ohagen P, et al. Decompression alone or decompression with fusion for lumbar spinal stenosis, five-year clinical results. Bone Joint J, 2024;106-B:705-712. https://pubmed.ncbi.nlm.nih.gov/38945544/
7. Gadjradj PS, Basilious M, Goldberg JL, et al. Decompression alone versus decompression with fusion in degenerative spondylolisthesis. Eur Spine J, 2023;32:1054-1067. https://pubmed.ncbi.nlm.nih.gov/36609887/
8. Pranata R, Lim MA, Vania R, Mahadewa TGB. Decompression alone versus decompression with fusion. Int J Spine Surg, 2022;16:71-80. https://pubmed.ncbi.nlm.nih.gov/35314509/
9. Peul WC, van Houwelingen HC, van den Hout WB, et al. Surgery versus prolonged conservative treatment for sciatica. N Engl J Med, 2007;356:2245-2256. https://pubmed.ncbi.nlm.nih.gov/17538084/
10. Peul WC, van den Hout WB, Brand R, et al. Prolonged conservative care versus early surgery in patients with sciatica, two year results. BMJ, 2008;336:1355-1358. https://pubmed.ncbi.nlm.nih.gov/18502911/
11. Bailey CS, Rasoulinejad P, Taylor D, et al. Surgery versus conservative care for persistent sciatica lasting 4 to 12 months. N Engl J Med, 2020;382:1093-1102. https://pubmed.ncbi.nlm.nih.gov/32187469/
12. Weinstein JN, Tosteson TD, Lurie JD, et al. Surgical vs nonoperative treatment for lumbar disk herniation, SPORT. JAMA, 2006;296:2441-2450. https://pubmed.ncbi.nlm.nih.gov/17119140/
13. Lurie JD, Tosteson TD, Tosteson A, et al. Long-term outcomes of lumbar spinal stenosis, eight-year results of SPORT. Spine, 2015;40:63-76. https://pubmed.ncbi.nlm.nih.gov/25569524/
14. Leven D, Passias PG, Errico TJ, et al. Risk factors for reoperation in patients treated surgically for intervertebral disc herniation. J Bone Joint Surg Am, 2015;97:1316-1325. https://pubmed.ncbi.nlm.nih.gov/26290082/
15. Ahn UM, Ahn NU, Buchowski JM, et al. Cauda equina syndrome secondary to lumbar disc herniation, a meta-analysis of surgical outcomes. Spine, 2000;25:1515-1522. https://pubmed.ncbi.nlm.nih.gov/10851100/
16. Najjar E, Muscogliati R, Trumble C, et al. Reassessing bladder recovery in cauda equina syndrome. Spine J, 2026. https://pubmed.ncbi.nlm.nih.gov/42480656/
17. Atalay B, Gadjradj PS, Sommer FS, et al. Natural history of degenerative spondylolisthesis. World Neurosurg, 2023;176:e634-e643. https://pubmed.ncbi.nlm.nih.gov/37271258/

See also: all our articles on musculoskeletal and pain.

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