[Significance of exact lateral roentgen documentation in Meyerding's grading of spondylolistheses].

The treatment of spondylolisthesis-in particular the indication of operation-is based on clinical symptoms as well as radiological criteria. For radiological techniques, the lateral profile, especially in function tests, is of importance. As a basic requirement the grade of Meyerding should be evaluated on x-ray in the exact lateral profile. We have observed, that even a slight rotation of the spine leads to misjudging of the real degree of vertebral dislocation. In 30 patients with spondylolisthesis of the lumbar spine the x-rays, made in exact lateral position, were compared with x-rays in 10 degrees rotation of the spine. On the average we measured an increase of vertebral dislocation of 3-4 mm. The increase was independent of the grade of Meyerding or the level of spondylolisthesis. The results could be verified by a spine of a human corpse.