[Study of the morphologic variations of the scaphocephaly. Deduction for their systematisation].

PURPOSE: The scaphocephaly is the most frequent craniosynostosis secondary to a premature synostosis of the sagittal suture. Despite this univocal pathogeny there are a great heterogeneity in the skull deformation and their systematisation stay imprecise. The aim of this study was to analyse the different morphology of the scaphocephaly by 3D CT-scan to clarify the different shapes.

MATERIAL AND

METHODS

This retrospective study was done from the morphometric analysis of forty-two 3D CT-scan (10 girls and 32 boys). The scaphocephaly was classified in two groups according to the systematisation of Stricker and Montaut: the sphenocephaly (large forehead) and the leptocephaly (narrow forehead). The variation of the calvaria shape was analysed and different index were calculated.

RESULTS

There were 30 sphenocephaly and 12 leptocephaly. Excepted for the forehead deformation there was a morphometric difference of the occipital pole that was backward rotated in the leptocephaly. In the two groups there were retro-coronal constriction (40.5%) or pre-lambdoid constriction (9.5%) independently of the sagittal synostosis degree.

CONCLUSIONS

The morphometric analysis shows that the deformation of the skull secondary to the premature synostosis of the sagittal suture can be different. The adaptative defect of the metopic suture can be to explain this difference. This deformation can be harmonious, or with a retro-coronal constriction resulting in a bitemporal narrowing, or with a pre-lambdoid constriction resulting in an occipital chignon. These results conduce to qualify the surgical correction to adapt at the different shapes.