Standing roentgenograms in spondylolisthesis.

Lateral roentgenograms of 50 patients with spondylolisthesis were made in the recumbent and standing positions and compared. Thirteen (26%) showed an increase in the percentage of displacement on standing. Those patients with demonstrable change appeared to have a higher incidence of severe symptomatology. Apparent spondylolysis on recumbent roentgenograms may change to spondylolisthesis on standing lateral roentgenograms. Degenerative spondylolisthesis may be more apparent on standing lateral roentgenograms.