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Spondylolysis and spondylolisthesis
Spondylolysis is a stress fracture of the pars interarticularis, usually at L5 in young athletes; when the vertebra slips forward over the one below it is spondylolisthesis, and a high-grade slip or one with neurological deficit is treated surgically.
Why it matters in the exam
The typical stem describes an adolescent in gymnastics, ballet, wrestling or jumping sports with low back pain that worsens on back extension and on standing on one leg with extension (the stork test), sometimes with tight hamstrings. An oblique radiograph shows a defect at the collar of the Scottie dog, but CT and MRI are more sensitive, and MRI can identify a stress reaction even before a fracture forms. Isthmic spondylolisthesis develops from this defect, usually at L5–S1, and in children it can progress during the growth spurt. Another common type is degenerative spondylolisthesis, mainly in older women at L4–L5, in which the arch is intact and the slip comes from facet joint wear; it usually causes spinal stenosis and neurogenic claudication. The Meyerding classification grades the slip by the percentage of the width of the vertebral body below. First-line treatment in most cases is conservative: temporary stopping of the aggravating activity, physiotherapy to strengthen abdominal and back muscles, and sometimes a brace. Surgery (fusion, sometimes with decompression) suits a slip of more than 50% in a growing child, a progressing slip, neurological deficit or pain persisting despite prolonged conservative care. In degenerative slip with stenosis, decompression with fusion is considered when symptoms are limiting. On examination of a child with a high-grade slip there is sometimes a palpable step in the lower back, a forward-tilted pelvis and a crouched gait from tight hamstrings. In return-to-sport questions, most young athletes return to full activity once pain has gone and strength is restored, even when the pars defect has not united on imaging, because a stable fibrous union is usually enough.
Key points
- Stress fracture of the pars, usually at L5, in young athletes.
- Pain on extension; the oblique radiograph shows a collar.
- Isthmic at L5–S1; degenerative at L4–L5 in older adults.
- Meyerding I–V by percentage of slip.
- Conservative first; fusion for a high-grade slip, progression or neurological deficit.
Summary table
| Meyerding grade | Percentage of slip | Usual approach |
|---|---|---|
| I | Less than 25% | Conservative; follow children during growth |
| II | 25–50% | Conservative in most cases; surgery for persistent pain or neurological deficit |
| III | 50–75% | In a growing child — consider fusion even without severe symptoms |
| IV | 75–100% | Fusion |
| V (spondyloptosis) | More than 100% | Fusion at a specialist centre |
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Sources
- Lovell and Winter's Pediatric Orthopaedics, 8th ed. (2020) — Spondylolysis and Spondylolisthesis
- Campbell's Operative Orthopaedics, 14th ed. (2021) — Spondylolisthesis
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.