Radiographical analysis concerning the etiology of degenerative spondylolisthesis of the lumber spine

The purpose of this articles is to evaluate radiographically degenerative spondylolisthesis of the kumber spine, with the main focus on the configuration of posterior elements. A comparative study between 49 cases of degnerative spondylolisthsis and 99 cases of other lumber disorders was performed, using 13 radiographical. The results cleary indicate the posterior elements of degenerative spondylolisthesis shifted horizontally and sagittally to allow slipping. This was due to the weak bony hook machanism. Furthermore, almost all facet joints were morphologically classified as sagittal or intermediate type. Another meaningful difference was the alignment of the lumber spine which showed an increase in both lordosis and lumbosacral angel. On the other hand, the level of Janoy's line was almost the same in both groups. These characteristic configurations could be the cause of listesis, although further study should be carried out to elucidate whether are oresent at the non-listhetic stage.