RÉSUMÉ
This study was carried out to establish a mathematical classification of normal soft tissue pattern by cluster analysis based on lateral cephalometric radiographic measurements. The sample consisted of 96 Egyptian adults [53 females and 43 males] having normal occlusion with pleasing face, balanced facial profile and competent lips with ages ranging between 18-25 years. For each subject linear and angular soft tissue measurements were recorded and ratios between the linear facial profile parameters were calculated. Two cluster analyses were applied for the collected data which reflected the size and shape of the normal soft tissue pattern. Each cluster analysis resulted in classification of normal sample into three clustered groups. Most of the linear and angular soft tissue parameters shoed significant differences between the centers of each cluster, with no obvious variation regarding the lower lip length and the degree of its protrusion with the upper lip in relation to soft tissue-nasion. However, clustering of the calculated ratios revealed that the length of the frontal third in relation to the total facial height, the prominence of the nose in relation to the nasal third length and the proportion of the upper and lower lip length to each other and in relation to the gnathic thirds were all considered as significant dependent factors in the differentiation between the shape of the soft tissue pattern within the three clustered groups
RÉSUMÉ
The Gill, White and Manning procedure of excision of the loose neural arch for the treatment of spondylolisthesis has fell into disrepute. More sophisticated and "anatomical" techniques entailing reduction, fusion etc. constitute now the treatment of choice. A prospective study has been conducted on 20 patients with first and second degrees lumbosacral and L4-5 spondylolisthesis treated by excision of the neural arch and herein presented. It proved safe and effective especially in the older age group