The term spondylolisthesis derived from the Greek spondylos, meaning “vertebra,” and olisthenein, meaning “to slip.”
Spondylolisthesis is defined as anterior or posterior slipping of one segment of the spine on the next lower segment.
Types
There are two clasifications of spondylolisthesis. One is by Wiltse, Newman, and Macnab’s classification of and other is by Marchetti and Bartolozzi.
Wiltse classification
It is based on etiological and topographical criteria. It is argued that it is difficult to predict progression or response to treatment
This classification scheme divides the spondylolisthesis in 5 types
Type I – Dysplastic
Congenital abnormalities of the upper sacral facets or inferior facets of the fifth lumbar vertebra that allow slipping of L5 on S1.
The congenital abnormalities of lumbosacral articulation include maloriented or hypoplastic facets, sacral deficiency or poorly developed pars interarticularis.
There is no pars interarticularis defect.
Type II – Isthmic
There is a defect in the pars interarticularis that allows forward slipping of L5 on S1.
There are three subtypes
A stress fracture of the pars interarticularis [Lytic type]
An elongated but intact pars interarticularis [Elongated type]
An acute fracture of the pars interarticularis
Type III – Degenerative
This lesion results from intersegmental instability of a long duration with subsequent remodeling of the articular processes at the level of involvement.
Type IV- Traumatic
This type results from fractures in the area of the bony hook other than the pars interarticularis.
Type V – Pathological
This type results from generalized or localized bone disease and structural weakness of the bone e.g osteogenesis imperfecta, infection
Marchetti and Bartolozzi attempted divided the condition into developmental and acquired forms.
To classify according to this classification, it must be first determined if the condition is developmental or acquired.
Classification of Marchetti-Bartolozzi
Developmental
High dysplastic
- With lysis
- With elongation
Low dysplastic
- With lysis
- With elongation
Acquired
Traumatic
- Acute fracture
- Stress fracture
Post surgery
- Direct surgery
- Indirect surgery
Pathological
- Local pathology
- Systemic pathology
Degenerative
- Primary
- Secondary
Most spondylolistheses in children and adolescents are developmental.
There is another classification by Meyerding which is based on percentage of slip
Grade 1: 25% of vertebral body has slipped forward
Grade 2: 50% of vertebral body has slipped forward
Grade 3: 75% of vertebral body has slipped forward
Grade 4: 100% of vertebral body has slipped forward
Grade 5: Vertebral body completely fallen off (i.e.,spondyloptosis)
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