Dr. Hiro K

Video 02

Spinal fusion or decompression alone? A spine surgeon’s honest answer

If a surgeon has proposed a spinal fusion, ask one question first: why fusion, and not decompression alone? Three good reasons, and what the trials found.

In short

  • Three good reasons for fusion: marked instability, a collapsed disc narrowing the nerve exit, and a lost lower-back curve.
  • Each extra level fused adds risk on the day of surgery and load on the levels left.
  • In the Swedish and Norwegian trials, adding fusion to decompression did not make people better off at two or five years.
  • Ask your surgeon: is fusion needed for something it truly fixes, or to raise the odds of a better result in the first year?

Summary

Most leg pain from the lower back comes from a squeezed nerve. Decompression takes away what is pressing on it. Fusion does that too, and then joins two or more vertebrae with screws, rods and often a spacer, so the movement between them stops for good.

There are three good reasons to fuse: marked instability (the joints at the back open widely every time you bend), a collapsed disc that narrows the opening where the nerve exits, and a lost curve of the lower back. When they apply, I recommend fusion myself, and I do fusions. What worries me is fusion across several levels.

Fusion is also proposed when a surgeon is not sure decompression alone will be enough, because many surgeons believe it raises the odds of relief in the short term. In people with stenosis, with or without a slipped vertebra, the large trials from Sweden and Norway found decompression alone did as well, at two years and at five. So ask why fusion is being proposed for you, and remember that decompression first does not close the door on fusion later.

Sources

  1. After a one-level fusion about 1 in 12 people needed a blood transfusion; after two levels, about 1 in 4.

    US surgical database, 12,407 posterior lumbar fusions. Transfusion: 8.6% (1 level), 23.4% (2 levels), 29.9% (3 levels). Hospital stay 3.5, 3.9 and 4.6 days. Other short-term complications changed little per added level.

    Bohl DD, Haws BE, Khechen B, et al. Impact of the number of levels on adverse events and length of stay following posterior lumbar fusion procedures. Clin Spine Surg. 2019;32(3):120-124. PubMed 30407262 · DOI

  2. In patients 65 and older, most had at least one complication after decompression and fusion, counting minor ones, and the rate rose with the number of levels fused.

    98 patients, average age 72. Complications in 78 (major in 21, minor in 69). The rate increased with age, blood loss, operating time and the number of levels. An older, single-centre series.

    Carreon LY, Puno RM, Dimar JR 2nd, Glassman SD, Johnson JR. Perioperative complications of posterior lumbar decompression and arthrodesis in older adults. J Bone Joint Surg Am. 2003;85(11):2089-2092. PubMed 14630835 · DOI

  3. For back pain alone, people who had fusion were no better off about 11 years later than people who went through intensive rehabilitation.

    Three randomised trials in Norway and the UK, 473 patients; 261 followed up after an average of 11.4 years. Disability score difference: -0.7 points on a 0-100 scale (no meaningful difference).

    Mannion AF, Brox JI, Fairbank JC. Comparison of spinal fusion and nonoperative treatment in patients with chronic low back pain: long-term follow-up of three randomized controlled trials. Spine J. 2013;13(11):1438-1448. PubMed 24200413 · DOI

  4. In lumbar stenosis, adding fusion to decompression did not give better results at two years or five, and meant a longer stay, more bleeding and higher cost.

    247 patients aged 50-80, with or without a slipped vertebra, randomised. Disability score at 2 years: 27 with fusion vs 24 without. Hospital stay 7.4 vs 4.1 days. Further spine surgery over 6.5 years: 22% vs 21%.

    Försth P, Ólafsson G, Carlsson T, et al. A randomized, controlled trial of fusion surgery for lumbar spinal stenosis. N Engl J Med. 2016;374(15):1413-1423. PubMed 27074066 · DOI

  5. The same Swedish trial at five years: disability was similar, and two outcomes favoured decompression alone.

    213 patients followed. Disability score 25 (decompression alone) vs 28 (with fusion). Quality of life was higher after decompression alone. Without a slipped vertebra, leg pain decreased in 80% after decompression alone vs 58% after fusion.

    Karlsson T, Försth P, Öhagen P, Michaëlsson K, Sandén B. Decompression alone or decompression with fusion for lumbar spinal stenosis: five-year clinical results from a randomized clinical trial. Bone Joint J. 2024;106-B(7):705-712. PubMed 38945544 · DOI

  6. In people with a slipped vertebra, decompression alone did as well as decompression plus fusion at two years.

    Norway, 267 patients with a slip of 3 mm or more. At least 30% less disability: 71.4% (decompression alone) vs 72.9% (with fusion). Reoperation within 2 years: 12.5% vs 9.1%.

    Austevoll IM, Hermansen E, Fagerland MW, et al. Decompression with or without fusion in degenerative lumbar spondylolisthesis. N Engl J Med. 2021;385(6):526-538. PubMed 34347953 · DOI

  7. The same Norwegian trial at five years: still no advantage from adding fusion.

    At least 30% less disability: 63% in both groups. New lumbar surgery by five years: 16% (decompression alone) vs 18% (with fusion).

    Kgomotso EL, Hellum C, Fagerland MW, et al. Decompression alone or with fusion for degenerative lumbar spondylolisthesis (Nordsten-DS): five year follow-up of a randomised, multicentre, non-inferiority trial. BMJ. 2024;386:e079771. PubMed 39111800 · DOI

  8. Getting the operation the surgeon would have chosen did not predict a better result.

    Surgeons recorded their preferred operation for 222 trial patients before randomisation. Good outcome: 75% when the patient got the surgeon’s choice vs 73% when not.

    Seip A, Hellum C, Fagerland MW, et al. Surgeon recommendation and outcomes of decompression with vs without fusion in patients with degenerative spondylolisthesis. JAMA Netw Open. 2025;8(1):e2453466. PubMed 39777439 · DOI

  9. One American trial found a modest benefit from adding fusion in a stable slipped vertebra.

    66 patients. Physical health score improved 15.2 with fusion vs 9.5 without; the disability score difference was not significant. Reoperation 14% with fusion vs 34% without.

    Ghogawala Z, Dziura J, Butler WE, et al. Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis. N Engl J Med. 2016;374(15):1424-1434. PubMed 27074067 · DOI

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