Wiltse classification of spondylolisthesis

The Wilste classification of spondylolisthesis is based on the etiology of the slip but does not grade severity nor assist with management ^1,2.

Usage

Typically, when reporting studies with spondylolisthesis, the Wiltse type is merely described without referring to its number, whereas the grade of spondylolisthesis is explicitly stated: e.g. "Grade 1 degenerative spondylolisthesis of L5 on S1" rather than "Grade 1, Type III spondylolisthesis".

Classification

The Wilste classification of spondylolisthesis is as follows ¹:

• type I (dysplastic/congenital): translation is secondary to an abnormal neural arch

• type II (isthmic): translation is secondary to a lesion involving the pars interarticularis

  • subtype a (lytic): secondary to stress fracture, in most cases attributed to repeated extension and/or twisting motions

  • subtype b (elongated pars): result of multiple injury/healing events leading to elongation of the pars

  • subtype c (acute pars fracture): secondary to a single event and is rare

• type III (degenerative): result of chronic instability and intersegmental degenerative changes

• type IV (post-traumatic): fracture in a region other than the pars leading to slippage

• type V (pathological): diffuse or local disease compromising the usual structural integrity that prevents slippage

• type VI (iatrogenic)

History and etymology

This classification was proposed by Leon L. Wiltse in 1981 ¹.