SPONDYLOLISTHESIS
One vertebra has slipped forward on the one below. The slip is not the pain.
It is an alarming word and an alarming picture, and the degree of slip correlates poorly with how much someone hurts. What matters is whether the segment is stable and whether anything is being compressed.
What it is
Spondylolisthesis is forward translation of one vertebral body on the one beneath it, most often L4 on L5 or L5 on S1. It is graded I to IV by how far it has moved. The two common causes are a stress fracture in the bony bridge behind the joint, typically from adolescent extension sport, and degenerative change in the facets that lets the segment drift with age.
Grade I and II are the overwhelming majority and are frequently found incidentally on imaging done for something else. Many people carry one for decades without symptoms.
What actually produces symptoms
- Segmental instability — the slip moving between flexion and extension views, which is a different finding from a slip that sits still.
- Foraminal narrowing at the level, compressing the exiting root and producing leg symptoms.
- Facet-mediated pain at the affected segment, which is common and testable. Facet syndrome.
- Central canal narrowing, producing distance-limited walking. Stenosis.
Notice that none of those is the slip itself. A stable grade I slip with no compression is a radiographic observation, not a diagnosis, and treating the number rather than the mechanism is how people end up with fusions that do not change their day.
What we do about it
- Flexion and extension X-rays to establish whether the segment actually moves. This is the question that changes management and it is skipped surprisingly often.
- Examine for root involvement and for the distance-limited pattern.
- Test the facets at that level with a diagnostic block where axial pain dominates.
- Build the segment a better muscular envelope — deep abdominal wall, multifidus, hip extensors. A segment stabilized by muscle behaves better than one left to its ligaments.
- Reserve fusion for demonstrated instability with a matching symptom pattern, or for progressive neurological deficit.
Extension is the provocative direction here. Programs built around repeated extension — some yoga, some gym work, some sports — frequently make this worse. Flexion-biased conditioning is usually better tolerated, which is the reverse of the advice a facet-free back gets.
Common questions
Will my slip get worse?
Most stable slips progress slowly or not at all, particularly in adults with degenerative rather than fracture-related cases. Progression is worth monitoring rather than assuming.
Do I need surgery?
Most people do not. Surgery has a clear role in demonstrated instability, in progressive deficit, and in stenosis at the level that has failed conservative care. Before you agree.
Can I still exercise?
Yes, and you should. Bias toward flexion-tolerant, core-stabilizing work and away from repeated end-range extension. Avoiding movement altogether removes the muscular support the segment most needs.
Related reading
- Spinal stenosis
- Lumbar facet syndrome
- What your imaging actually showed
- Physical therapy for back pain
Ask whether your slip actually moves
Flexion and extension views answer it, and the answer changes everything downstream. Bring whatever imaging you already have.
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Sources
- Bydon M et al. Degenerative Lumbar Spondylolisthesis: Definition, Natural History, Conservative Management, and Surgical Treatment. Neurosurgery clinics of North America, 2019. PubMed 31078230
- Mohile NV et al. Spondylolysis and Isthmic Spondylolisthesis: A Guide to Diagnosis and Management. Journal of the American Board of Family Medicine : JABFM, 2022. PubMed 36526328
- Gadjradj PS et al. Decompression alone versus decompression with fusion in patients with lumbar spinal stenosis with degenerative spondylolisthesis: a systematic review and meta-analysis. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2023. PubMed 36609887
- Chan AK et al. Summary of Guidelines for the Treatment of Lumbar Spondylolisthesis. Neurosurgery clinics of North America, 2019. PubMed 31078236