What is Spondylolisthesis?
Spondylolisthesis occurs when one vertebra slips forward over the vertebra below it, causing instability of the spinal segment. The severity is graded on a scale of I–IV (Meyerding classification), based on the percentage of slippage. Grade I (0–25%) is managed conservatively in most cases, while Grade III–IV (>50% slip) typically requires surgical stabilisation.
The most common types are degenerative spondylolisthesis (occurring in older adults at L4-L5 due to disc and facet degeneration) and isthmic spondylolisthesis (occurring at L5-S1 due to a stress fracture in the pars interarticularis, often in young athletes).
Symptoms
Lower back pain, often worsened by standing and walking
Leg pain, numbness, or tingling (from nerve compression)
Tight hamstrings — abnormal gait in severe cases
Pain relieved by sitting and bending forward
Visible "step" in the lower back (high-grade slips)
Neurogenic claudication — inability to walk long distances
Types
- Degenerative (Type III) — most common in adults over 50; facet joint and disc degeneration
- Isthmic (Type II) — pars interarticularis stress fracture; common in young athletes
- Dysplastic (Type I) — congenital abnormality of the sacrum
- Traumatic (Type IV) — acute fracture following injury
- Pathological (Type V) — due to bone disease (tumour, Paget's)