Synopsis
Classify vertebral slip by cause and age, recognise instability and neural compromise, choose appropriate standing and cross-sectional imaging, and separate adult degenerative from adolescent pars-related pathways.
- Spondylolisthesis is translation of one vertebra relative to another. Degenerative slip usually affects older adults at L4–5 with intact pars; isthmic slip follows a pars defect, often at L5–S1 and may arise during growth.
- A slip can be incidental or cause extension-related back pain, radiculopathy, neurogenic claudication or deformity. Symptoms and neurological findings—not grade alone—set clinical urgency.
- Keep age-specific pathways separate: an adolescent athlete with pars stress injury is not managed by an adult degenerative-stenosis algorithm, and the adult NASS isthmic guideline explicitly excludes paediatric patients.
Key red flags
New bladder, bowel or sexual dysfunction or saddle numbness with severe radiating low-back pain requires immediate cauda equina assessment.
Rapidly progressive motor deficit, bilateral weakness or loss of walking needs urgent spinal review and imaging.
High-energy trauma, marked deformity or severe pain with neurological change raises unstable injury; apply a trauma pathway rather than assuming chronic slip.
Fever, immune compromise, cancer history, weight loss or destructive imaging features suggest infection or malignancy as the cause of instability.
A growing child or adolescent with progressive slip, neurological deficit, marked hamstring tightness or abnormal posture needs paediatric spinal specialist review.
Upper-motor-neuron signs or a sensory level cannot be explained by an isolated lumbar slip and require cord localisation.
Growth remaining, higher-grade slip, abnormal posture, hamstring spasm, neurological symptoms or documented progression warrant paediatric spinal specialist assessment.
New sacral dysfunction or rapidly progressive weakness requires emergency evaluation independently of the known chronic slip.
Investigation priorities
Confirm translation under load, identify level, estimate Meyerding grade and assess alignment.
Management branches
An adult has concordant mechanical, radicular or claudicant symptoms without emergency neurological compromise.
- Classify the slip and clinical syndrome, explain that radiographic grade alone does not mandate surgery, and begin diagnosis-specific activity, exercise and functional rehabilitation with medicine-risk review.
- If disabling symptoms persist, obtain standing and management-changing cross-sectional imaging and refer for specialist correlation of neural compression, dynamic instability, deformity, comorbidity and goals.