Spondylolisthesis
From WikiMSK
Spondylolisthesis (plural: spondylolistheses) is the slippage of one vertebra relative to the one below. It can occur anywhere in the spine, but is most commonly seen in the lumbar spine, particularly in association with spondylolysis at L5/S1 and with degenerative changes at L4/L5.
Aetiology
The Wiltse classification scheme (1981) is used to categorise spondylolisthesis on an aetiological basis. [1]
- Type I is dysplastic/congenital: There is an abnormal neural arch with rounding of the superior ventral surface of the S1 vertebra. This leads to L5 translating anteriorly. This type has the highest progression risk at 32%.
- Type II is isthmic: There is a lesion of the pars interarticularis. Sports-related isthmic type progresses in 4%.[2]
- Subtype II A (lytic): secondary to stress fracture (spondylolysis)
- Subtype II B (elongated pars): secondary to multiple injury and healing cycles leading to an elongated pars
- Subtype II C (acute pars fracture): secondary to a single event and is rare.
- Type III is degenerative: This is when degenerative changes have lead to ligamentous instability affecting the ligamentum flavum, capsule of the facet joints, and other ligaments. The facet joints are then able to slip forward. This generally occurs at L4/5. It is more common in females over 40.
- Type IV is post-traumatic: There is a fracture in a region other than the pars which leads to slippage.
- Type V is pathologic: There is diffuse (generalised bone disease) or local bone disease (e.g. a lytic pars tumour) which compromises the structural integrity. It may appear sclerotic on radiographs.
- Type VI is iatrogenic
Imaging
The Meyerding classification is used to classify the severity of slippage. It divides the superior endplate of the caudal vertebra into four quarters. The grade is dependent on the location of the posteroinferior corner of the cephalad vertebra.[3]
- Grade I: 0-25%
- Grade II: 26-50%
- Grade III: 51-75%
- Grade IV: 76-100%
- Grade V (spondyloptosis): >100%
References
- ↑ Wiltse, Leon L.. “Classification, Terminology and Measurements in Spondylolisthesis.” The Iowa Orthopaedic Journal vol. 1 (1981): 52–57. Full Text
- ↑ McPhee IB, O'Brien JP, McCall IW, Park WM. Progression of lumbosacral spondylolisthesis. Australas Radiol. 1981 Mar;25(1):91-5. doi: 10.1111/j.1440-1673.1981.tb02225.x. PMID: 7271629.
- ↑ Patrick Rock et al. Spondylolisthesis grading system. Radiopaedia.org. https://radiopaedia.org/articles/spondylolisthesis-grading-system
