[CDH--preliminary report on a primary stable ventral lumbar spine instrumentation].

CDH-instrumentation was developed by the principles of an improved stability in ventral operation procedure and by the possibility of treating all anterior spinal diseases. The implantation of anterior plates and drawers, the use of rods fixed within the implant in non-parallel directions thus automatically providing for a locking mechanism against displacements, the prevention of dislocation of the cancellous bone screws and the DDT-principle were further requirements. The spine can be corrected according to the three-dimensional anatomy by distraction-, compression and rotational forces, a postoperative external support is unnecessary. After the application of the method in 50 patients (mono- and multisegmental) the excellent stability could be proved.