Dr. Hiro K

Video 03

Will spinal fusion lead to more surgery? A spine surgeon’s 10-year answer

A fusion is permanent, and the spine around it keeps working. What the research shows ten years after a lumbar fusion, who is most at risk, and what to ask your surgeon.

In short

  • X-ray wear next to a fusion is common; wear that causes symptoms is much less common.
  • Another operation at the next level: about 1 in 7 by five years, about 1 in 5 by ten (one large series; others report lower).
  • Every extra level fused raises the risk: at the next level, of the bones not healing together, and of new sacroiliac joint pain.
  • Ask your surgeon: how many levels and why that many, what is my risk at the next level, and what is the plan if it wears out?

Summary

A fusion turns two or more vertebrae into one solid block that never moves again. You keep bending, twisting and standing up, so the work that level used to do goes to the levels above and below. Over the years those neighbours can wear out faster. This is called adjacent segment disease.

How often depends on how you count. Wear on an X-ray is common, but wear that causes symptoms is much less so, and in long-term trial follow-up the thinner discs next to a fusion were not linked to pain or disability. In a study of a thousand fusions, about 1 in 7 people had another operation at the next level by five years and about 1 in 5 by ten. The biggest factor is how many levels are fused: about 1 in 6 after one level, and 4 in 10 after three or four.

A second operation goes through scar tissue and usually does less than the first, and a few people go on to a long corrective fusion. Most people never enter that chain, and fusion done for the right reason often works well for years. But a fusion is a decision about the next twenty years of your spine, not just the next six months.

Sources

  1. After lumbar surgery, wear at the neighbouring level showed on X-rays in about 1 in 4 people, but caused symptoms in fewer than 1 in 10.

    Review of 94 studies, 34,716 patients. Lumbar spine: changes on X-ray 26.6%, symptoms 8.5% (pooled).

    Xia XP, Chen HL, Cheng HB. Prevalence of adjacent segment degeneration after spine surgery: a systematic review and meta-analysis. Spine (Phila Pa 1976). 2013;38(7):597-608. PubMed 22986837 · DOI

  2. About 13 years after randomised trials, the disc above a fusion was thinner than in people treated without surgery, but that had no link to pain or disability.

    Four randomised trials, 355 patients with usable X-rays at a mean of 13 years. Disc height at the level above: 0.44 standard deviations lower with fusion. No correlation with disability or pain scores.

    Mannion AF, Leivseth G, Brox JI, et al. ISSLS Prize winner: long-term follow-up suggests spinal fusion is associated with increased adjacent segment disc degeneration but without influence on clinical outcome: results of a combined follow-up from 4 randomized controlled trials. Spine (Phila Pa 1976). 2014;39(17):1373-1383. PubMed 24859589 · DOI

  3. After a lumbar fusion, about 1 in 7 people had surgery at the next level by five years and about 1 in 5 by ten, rising steeply with the number of levels fused.

    1,000 fusions in 912 patients, Australia. Further surgery for adjacent segment disease: 13.6% at 5 years, 22.2% at 10. At 10 years: 16% (1 level), 31% (2 levels), 40% (3-4 levels). Older age, stopping at L5 and a laminectomy next to the fusion also raised the risk.

    Sears WR, Sergides IG, Kazemi N, et al. Incidence and prevalence of surgery at segments adjacent to a previous posterior lumbar arthrodesis. Spine J. 2011;11(1):11-20. PubMed 21168094 · DOI

  4. A Japanese series found a lower rate, and very few people needed a third operation for a second worn-out neighbour.

    1,000 patients, average age 67, followed for an average of 8.3 years. Revision for adjacent segment disease 9.0%, on average 4.7 years after surgery. Second and third episodes: 1.1% and 0.4%. Longer fusions had more.

    Okuda S, Yamashita T, Matsumoto T, et al. Adjacent segment disease after posterior lumbar interbody fusion: a case series of 1000 patients. Global Spine J. 2018;8(7):722-727. PubMed 30443483 · DOI

  5. Removing bone at the level next to a fusion, in the same operation, raised the rate of adjacent segment disease and of further surgery.

    789 patients. Adjacent segment disease: 57.5% with a laminectomy next to the fusion vs 35.2% without. Revision surgery: 22.1% vs 13.5%.

    Simonetta B, Adeniyi B, Corbett A, et al. Laminectomy adjacent to instrumented fusion increases adjacent segment disease. Spine (Phila Pa 1976). 2025;50(3):196-200. PubMed 38597215 · DOI

  6. Every extra level fused raised the risk that the bones never heal together.

    Review of 12 studies. The number of fused levels was the only surgical risk factor that held up (odds ratio 1.35 per level). Age and smoking also mattered.

    Boonsirikamchai W, Wilartratsami S, Ruangchainikom M, et al. Pseudarthrosis risk factors in lumbar fusion: a systematic review and meta-analysis. BMC Musculoskelet Disord. 2024;25(1):433. PubMed 38831392 · DOI

  7. Stiffness after fusion depended on how many levels were fused. After one level, people were actually bothered by stiffness less than before surgery; after three or more, they tended to notice it more.

    62 patients followed for at least 2 years. Stiffness-related limitation improved significantly after 1-level fusion and rose after 3-4 and 5+ levels (not statistically significant in this small study). 97% said they would have the same operation again.

    Hart RA, Marshall LM, Hiratzka SL, et al. Functional limitations due to stiffness as a collateral impact of instrumented arthrodesis of the lumbar spine. Spine (Phila Pa 1976). 2014;39(24):E1468-E1474. PubMed 25202930 · DOI

  8. In injured workers who had fusion for disc degeneration, fewer returned to work after a multilevel fusion than after a one-level fusion.

    US workers’ compensation, 937 patients. Back at work within 2 years and staying there: 21.7% after multilevel fusion vs 28.1% after one level.

    Anderson JT, Tye EY, Haas AR, et al. Multilevel lumbar fusion is a risk factor for lower return to work rates among workers’ compensation subjects with degenerative disc disease. J Surg Orthop Adv. 2018;27(3):209-218. PubMed 30489246

  9. A second fusion for a worn-out neighbour did less than the first, and some people went on to a long corrective fusion.

    47 patients who had a repeat fusion after a one-level fusion, Japan. Recovery rate 37.2%; results were worse than after the first operation. 11% later needed a long corrective fusion. The authors call it a chain of reoperations.

    Nagamoto Y, Okuda S, Matsumoto T, et al. Preoperative pelvic incidence minus lumbar lordosis mismatch in repeat posterior lumbar interbody fusion induces subsequent corrective long fusion. World Neurosurg. 2021;154:e762-e769. PubMed 34365048 · DOI

  10. Five years after fusion, three in four people showed new wear in the sacroiliac joints, against fewer than four in ten people of the same age without surgery.

    Prospective CT study: 32 fusion patients vs 34 age-matched people. New sacroiliac joint wear: 75% vs 38.2%. More common when the fusion included the sacrum.

    Ha KY, Lee JS, Kim KW. Degeneration of sacroiliac joint after instrumented lumbar or lumbosacral fusion: a prospective cohort study over five-year follow-up. Spine (Phila Pa 1976). 2008;33(11):1192-1198. PubMed 18469692 · DOI

  11. New sacroiliac joint pain after fusion became more common as more levels were fused.

    262 patients, Japan. New sacroiliac joint pain: 5.8% (1 level), 10.0% (2), 20.0% (3), 22.5% (4 or more).

    Unoki E, Abe E, Murai H, et al. Fusion of multiple segments can increase the incidence of sacroiliac joint pain after lumbar or lumbosacral fusion. Spine (Phila Pa 1976). 2016;41(12):999-1005. PubMed 26689576 · DOI

  12. After long fusions to straighten a curved spine, about 7 in 10 people had at least one complication within two years, and more than 1 in 4 needed another operation.

    Prospective multicentre study, 291 adults with spinal deformity followed for at least 2 years. At least one complication: 69.8%. At least one revision: 28.2%.

    Smith JS, Klineberg E, Lafage V, et al. Prospective multicenter assessment of perioperative and minimum 2-year postoperative complication rates associated with adult spinal deformity surgery. J Neurosurg Spine. 2016;25(1):1-14. PubMed 26918574 · DOI

  13. After long fusions, about 1 in 4 people developed a forward bend just above the top of the fusion, although it did not lower their outcome scores.

    81 adults with long fusions for deformity, followed for an average of 5.3 years. Proximal junctional kyphosis: 26%. Outcome scores were not lower in those who had it.

    Glattes RC, Bridwell KH, Lenke LG, et al. Proximal junctional kyphosis in adult spinal deformity following long instrumented posterior spinal fusion: incidence, outcomes, and risk factor analysis. Spine (Phila Pa 1976). 2005;30(14):1643-1649. PubMed 16025035 · DOI

  14. Decompression alone is not free of further surgery either: at four years its reoperation rate matched a simple fusion.

    US Medicare, 31,543 operations for lumbar stenosis. Reoperation by 4 years: 10.7% after decompression alone and after simple fusion; 13.5% after complex fusion.

    Deyo RA, Martin BI, Kreuter W, et al. Revision surgery following operations for lumbar stenosis. J Bone Joint Surg Am. 2011;93(21):1979-1986. PubMed 22048092 · DOI

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