Wiltse classification (spondylolisthesis)
Spondylolisthesis can be classified according to broad etiologies as described by Wiltse in 1981 . Typically when reporting studies with spondylolisthesis the Wiltse type is merely stated 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".
- 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)