Spondylolisthesis dysplastic

The research recently done by the Iowa group is fascinating to me. In my mind it confirms all my ideas about spondylolisthesis [8]. They simply potted immature calf spines and stressed them. The slip of the vertebra occurred at the growth plate much like slipped capital femoral epiphysis. If we can use this model as we think about high dysplastic spondylolisthesis with increased lordosis we begin to realize why the sacrum and L5 look the way they do in spondylolisthesis [3]. 

In dysplastic spondylolisthesis, many factors could be of importance for progressive deformity anatomically, dysplastic elements of lumbo-sacral junction, but also high angle of incidence which increases the lever arm of weight bearing in the lumbo-sacral area and resultant shear forces. 

There is a wide discussion about limited fusion to L5 or extension to L4. In severe dysplastic spondylolisthesis, L5 is generally hypothrophic, with a pseudo-aspect of retrolisthesis of L4 or L5. 

In dysplastic spondylolisthesis, the incidence has been found to be higher than in normal population (up to 80-90°, compared to 50° normal). Incidence is not corrected by the reduction of spondylolisthesis, and despite correction of the lumbo-sacral kyphosis and the retroversion of the pelvis, the gravity line stays still more anterior to the lumbo-sacral junction than in normal population. The only way to modify this factor would be to do a pelvis osteotomy. 

True spondyloptosis is only seen in cases of isthmic-dysplastic spondylolisthesis. It is never observed in the lytic spondylolisthesis. The significant difference between lytic and dysplastic types of slippage is that the dys-plastic type occurs together with lumbosacral kyphosis. 

The occurrence of the lumbosacral kyphosis, which always occurs together with retroversion of the pelvis and thus with retroversion of the sacrum, is not pathogenetically clarified. Looking at the developmental course of isthmic-dysplastic spondylolisthesis, the following observations can be made ... 

Fig. 3. Behavior of the positional and spinal parameters in a 9-year old child with dysplastic spondylolisthesis tremendous changes of the positional parameters, but also of the entire spinal parameters with flattening of the lumbar lordosis and the thoracic kyphosis, including displacement of the gravityline anterior to the center of the femoral head...

A 15 year old female patient isthmic-dysplastic spondylolisthesis L5/S1. 

Dysplastic spondylolisthesis is a congenital abnormality most typically of the first sacral or fifth lumbar neural arch. This defect generally becomes apparent during childhood or adolescence. This can be diagnosed on lateral view x-rays of the lumbar spine. 

This is an important distinction when one is attempting to understand spondylolisthesis. Developmental spondylolisthesis is the one that severely progresses [6]. What causes spondylolisthesis and spondyloptosis If we agree that spondylolisthesis must be present before spondyloptosis occurs, then we have to use a classification to help us understand this. Spondyloptosis is usually seen in high grade dysplastic type of developmental spondylolisthesis. 

The indication for surgery in dysplastic high grade slips spondylolisthesis concerns three elements deformity, instability-progression and neurological impairment. 

Only dysplastic (congenital) spondylolisthesis can lead to the complete picture of spondyloptosis. Its therapies are still controversially discussed today. The therapeutic palette ranges from therapeutic nihilism to fusion in situ, to complete reduction of the lumbo-sacral junction. 

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