Lumbar spinal stenosis: when walking becomes the problem
A characteristic pattern: walking a distance, having to stop, and being able to continue after sitting for a moment.
Before you read on. This article is general information for
patients. It cannot be used to reach a diagnosis and does not replace a
consultation: similar symptoms can have very different causes, and only an
in-person assessment — your history, your examination and your imaging — can
establish what is happening and what suits you. If something here worries you,
the right step is to discuss it with a doctor, not to draw conclusions.
Spondylolisthesis is the forward slippage of one vertebra over the one immediately below it. It almost always occurs in the lower lumbar spine: L4 over L5, or L5 over S1.
It is a finding that alarms people when it appears in a radiology report. Context helps: many people live with mild spondylolisthesis for decades without any symptoms.
What determines treatment is not how far the vertebra has slipped, but whether that slippage is compressing nerves, whether it is unstable, and how much it is limiting your life.
The types: they are not all the same
Degenerative
The most common. It appears after age 50–60, more often in women and typically at L4-L5. The facet joints and disc wear out, lose their holding capacity, and the vertebra slips. It is almost always accompanied by lumbar spinal stenosis.
Isthmic
Caused by a defect in the pars interarticularis, the bone bridge connecting the facets. It usually originates in adolescence, often in athletes performing repeated hyperextension — gymnastics, diving, football — and can stay silent for years. Typical at L5-S1.
Others
- Traumatic: from an acute fracture
- Pathological: from tumour or infection weakening the bone
- Dysplastic: from a congenital malformation of the facets
- Iatrogenic: after previous surgery that removed too much supporting bone
The Meyerding grades
| Grade | Slippage | Behaviour usually described in the literature |
|---|---|---|
| I | 0 – 25% | The most common. Many are asymptomatic. Conservative management first. |
| II | 25 – 50% | Often symptomatic. May need surgery if nerves are compressed. |
| III | 50 – 75% | Usually symptomatic. Surgery clearly enters consideration. |
| IV | 75 – 100% | Significant deformity. Surgery in most cases. |
| V (spondyloptosis) | > 100% | The vertebra has dropped in front of the one below. Rare and complex. |
To repeat the important point: grade alone does not decide surgery. A grade I with severe stenosis and disabling pain is operated on sooner than an asymptomatic grade II found incidentally.
Symptoms
- Mechanical back pain: worse standing or walking for a long time, better sitting or leaning forward
- Pain radiating into the legs if the nerve root is compressed at its exit
- Neurogenic claudication: leg pain, heaviness or cramping after walking a certain distance, forcing you to stop, relieved by sitting
- Stiffness and difficulty extending the back
- In advanced cases, visible changes in posture and gait
A clinically useful detail: patients often say they walk better pushing a shopping trolley or going uphill. Leaning forward opens the canal and eases symptoms.
How it is diagnosed
- Standing plain X-rays. Essential. Lying down, the slippage can reduce and go unnoticed.
- Dynamic X-rays in flexion and extension. These show whether the segment is unstable — whether the slippage changes with movement. This carries the most weight in the surgical decision.
- MRI. Shows nerve compression and the state of the disc and roots.
- CT. Better for the pars defect and bony anatomy before surgery.
If you were diagnosed with spondylolisthesis from a lying-down MRI alone, information is missing. Standing and dynamic X-rays are essential to determine whether there is instability.
Treatment without surgery
- Targeted physiotherapy for core and stabiliser strengthening, emphasising lumbopelvic control
- Avoiding hyperextension and heavy axial loading
- Weight control — directly reduces load on the segment
- Analgesia and anti-inflammatories during acute flares
- Injections — epidural or facet — in selected cases
Many patients stabilise here and need nothing more. Interestingly, in degenerative spondylolisthesis the slippage tends to self-stabilise over time as the segment stiffens.
When surgery is indicated
- Progressive neurological deficit: advancing loss of strength
- Disabling neurogenic claudication: you can no longer walk the distances your daily life requires
- Pain not settling after at least 3–6 months of well-conducted conservative treatment
- Demonstrated instability on dynamic X-rays
- Progression of slippage on serial follow-up
- Cauda equina syndrome → emergency
What is done in the operating room
- Decompress: free the trapped nerve roots
- Stabilise: fix the slipped segment so it stops moving, using pedicle screws and an interbody spacer restoring disc height (TLIF, PLIF or XLIF depending on the case)
Today much of this surgery is performed with minimally invasive technique and 3D navigation: the position of each screw is verified with imaging inside the operating room before finishing, and muscle is split rather than cut. That means less blood loss and shorter recovery than classic open surgery.
After surgery
Decompression relieves leg pain relatively quickly. Bone fusion, by contrast, is a biological process taking months: bone must grow and unite the vertebral bodies. The postoperative course therefore has phases:
- First weeks: progressive walking, avoiding lifting, wound care
- 1–3 months: gradual return to activity; desk work before physical work
- 3–12 months: fusion consolidates; verified with follow-up imaging
Smoking is the modifiable factor that most affects fusion: it significantly reduces the chance that bone will consolidate. Stopping smoking before a fusion is not generic health advice — it is part of the treatment.
What patients ask most
Does spondylolisthesis get worse over time?
Not necessarily. In the degenerative form, slippage usually progresses little and often tends to self-stabilise as the segment stiffens. In the isthmic form in adolescents, imaging follow-up is advisable because it can progress during growth. Progression is monitored with serial X-rays.
Can I exercise with spondylolisthesis?
Yes, with adaptations. Core and stabiliser strengthening is recommended, while avoiding repeated lumbar hyperextension and heavy axial loading. Walking, swimming, stationary cycling and motor control work are usually well tolerated. Ideally a physiotherapist should adapt the programme to your grade and symptoms.
Does a grade I need surgery?
Almost never as a first step. Most grade I cases are managed conservatively and many are asymptomatic, discovered incidentally on an X-ray ordered for another reason. Surgery is considered if there is symptomatic nerve compression, demonstrated instability, or disabling pain not responding to treatment.
What is the difference between spondylolysis and spondylolisthesis?
Spondylolysis is the defect or stress fracture in the pars interarticularis, without the vertebra having slipped. Spondylolisthesis is the slippage itself. Spondylolysis can progress to spondylolisthesis if the defect allows the vertebra to slide, but this does not always happen.
How long before returning to work after a lumbar fusion?
It depends on the type of work. For office work, many patients return between 4 and 8 weeks. For physical work involving lifting, the timeframe usually extends to 3–6 months, conditional on fusion consolidating, which is verified with imaging. The schedule is individualised at each postoperative review.
Written and reviewed by Dr. Ricardo Bermúdez, neurosurgeon. Last reviewed: 2026-09-09.
General informational content. It is not medical advice, does not create a doctor-patient relationship, and must not be used to self-diagnose or to decide on treatment. Outcomes vary from person to person. If you have symptoms, see a doctor.
