Sonographic measurement of vertebral dislocation in spondylolisthesis

: The vertebral dislocation in spondylolisthesis was measured by both sonography and roentgenography in 20 patients with spondylolysis and 6-28 mm of spondylolisthesis. The two methods were applied independently of each other. The difference between the sonographic and roentgenographic measure of vertebral dislocation was 0-3 mm (mean 1.3 mm). The accuracy of sonography is sufficient for clinical work. The advantage of sonography is that the radiation burden of patients with spondylolysis can be decreased by replacing roentgenographic follow-up with sonography.