How is lumbar spondylolysis and spondylolisthesis classified?

Updated: Jul 08, 2020
  • Author: Beth B Froese, MD; Chief Editor: Stephen Kishner, MD, MHA  more...
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Answer

Wiltse, Macnab, and Newman developed a classification to help outline causes of vertebral translation in an anterior direction. [3, 4] Their categories include the following:

  • Type I: Congenital spondylolisthesis

  • Type II: Isthmic spondylolisthesis

  • Type III: Degenerative spondylolisthesis

  • Type IV: Traumatic spondylolisthesis

  • Type V: Pathologic spondylolisthesis

Type I: Congenital spondylolisthesis is characterized by presence of dysplastic sacral facet joints allowing forward translation of one vertebra relative to another. Orientation of facets in an axial or sagittal plane may allow for forward translation, producing undue stress on the pars, resulting in a fracture.

Type II: Isthmic spondylolisthesis is caused by the development of a stress fracture of the pars interarticularis.

Type III: Degenerative spondylolisthesis is commonly caused by intersegmental instability produced by facet arthropathy. This variation usually occurs in the adult population and, in most cases, does not progress beyond a grade I spondylolisthesis (see grading system below). [5]

Type IV: Traumatic spondylolisthesis can, in rare instances, result from acute stresses (trauma) to the facet or pars.

Type V: Any bone disorder may destabilize the facet mechanism producing pathologic spondylolisthesis. Iatrogenic spondylolisthesis, lastly, may occur if an overzealous surgeon performs too great of a facetectomy.


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