[Indication for the surgical correction of severe spondylolisthesis and modification of incorrect lumbar posture].

In the last few years, the operative treatment of severe spondylolisthesis has aimed to reduce the gliding movement between the vertebral bodies proceeding then to a spondylodesis. So far, various questions have remained open. When, with which techniques and with which patients should the reduction of the vertebral gliding be performed? How do these results compare with the spondylolisthesis fused operatively "in situ" without any correction at the same time? In order to answer the various questions raised, we examined patients operatively treated with spondylolisthesis of more than 50%, both clinically and radiologically. 20 patients with a ventral spondylodesis and reposition were compared with 98 patients having had a dorsal fusion without reposition. In most cases of progressive vertebral gliding, it is possible to effect alignment of the lumbar curvature even with complex procedures e.g. Halo-Pelvic Traction or usage of Harrington Instruments. The reposition of the spondyloptosis has a positive influence on the Pelvic Tilt.