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Revision Spine Surgery
Pseudarthrosis Revision
An in-depth, evidence-based explanation of surgery for a spinal fusion that has not healed — diagnosing a non-union and revising it to achieve a solid fusion.
When a spinal fusion is performed, the aim is for the bone to knit solidly across the segment, so that it becomes one continuous, stable unit. Usually this happens. Occasionally it does not, and the segment fails to fuse — a condition called pseudarthrosis, or non-union. A non-union can cause ongoing pain and can lead to the metalwork loosening or breaking as it continues to take load that healed bone should be sharing. Pseudarthrosis revision is surgery to correct a failed fusion and give the bone the best possible chance of finally uniting. This page explains how it is diagnosed and treated.
For information only — not medical advice. The content on this page is patient education to help you understand a condition or treatment. It is not a substitute for personalised assessment by a qualified clinician. Always consult your doctor or specialist about your own symptoms, diagnosis, and treatment decisions.
What pseudarthrosis is
A pseudarthrosis is a fusion that has not become solid — literally a "false joint" where the bone should have bridged. It may cause persistent or recurrent pain around the fused segment, and because the bone is not sharing load, the implants are under continued stress and can loosen or fracture over time. Not every non-union is painful, so the decision to revise depends on symptoms as well as imaging. Confirming a pseudarthrosis usually needs careful assessment, often including a CT scan, because plain films can be misleading.
Why fusions sometimes fail
Several factors make a non-union more likely, and understanding them shapes the revision. Smoking strongly impairs bone healing and is one of the most important modifiable risks. Poor bone quality (osteoporosis) reduces the stability of the construct and the biological capacity to heal. Mechanical factors — such as inadequate fixation, or a long fusion reaching the lower spine — and biological factors all play a part. A successful revision addresses as many of these as possible, not just the mechanics.
How revision can be done
Revising a pseudarthrosis aims to improve both the biology and the mechanics of fusion. The non-union is re-exposed, the surfaces are freshened and re-grafted with new bone graft, and the fixation is reinforced or revised to create a stiffer, better-supported environment for healing — for example by adding an interbody cage, extending fixation, or supplementing an anterior fusion with posterior support. Alongside this, modifiable factors such as smoking and bone health are optimised. The combination gives the best chance of a solid union second time around.
What the evidence shows
The evidence guides pseudarthrosis revision. Long-term outcome studies of revision fusion for lumbar pseudarthrosis show that meaningful improvement and union are achievable. In the cervical spine, meta-analyses show that revision — particularly adding posterior fixation — achieves high union rates for symptomatic pseudarthrosis. Studies of revision after instrumented fusion, and of the critical length of fusion at the lumbosacral junction, inform the mechanical strategy. This literature supports a revision that tackles both the biology and the mechanics of the failed fusion.
What to expect
Pseudarthrosis revision is planned around confirming the non-union, understanding why it failed, and optimising the factors within reach before and around surgery. The realistic benefits, the risks — higher than for first-time surgery — and the alternatives are discussed in detail. The goal is a solid, stable fusion, with rehabilitation tailored to the operation and with attention to the modifiable factors that support healing.
Disclaimer. The information provided on this page is intended for educational purposes only and should not be considered personalised medical advice. Every patient is different, and treatment options, risks, expected recovery and outcomes depend upon an individual's diagnosis, previous surgery, bone health, general health and personal circumstances. Decisions regarding treatment should always be made following consultation with your treating spinal surgeon or healthcare professional.
Evidence & further reading
- —Adogwa O, et al. Long-term outcomes of revision fusion for lumbar pseudarthrosis. J Neurosurg Spine 2011. (PMID 21699473)
- —Chen Z, et al. Clinical and fusion results after treatment of symptomatic cervical pseudarthrosis: a meta-analysis. 2015. (PMID 25844290)
- —Kim JH, et al. Outcomes of revision surgery after instrumented posterolateral fusion: pseudarthrosis versus adjacent segment disease. 2017. (PMID 28670415)
- —Kim YJ, et al. Critical length of fusion requiring additional fixation to prevent non-union of the lumbosacral junction. Spine 2010. (PMID 20195201)
- —Risk factors affecting lumbosacral pseudarthrosis in multi-segmental fusion: a CT-based study. 2025. (PMID 40381029)
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