[Halm-Zielke instrumentation (Munster Anterior Double Rod System) as an improvement over Zielke-VDS. Surgical method and preliminary results].

INTRODUCTION AND AIM OF THE STUDY

Halm-Zielke Instrumentation (HZI), in german speaking countries also named the Münster Anterior Doublerod System, was developed to eliminate the disadvantage of VDS-Zielke in terms of lack of primary stability. Additionally sagittal plane control should be improved. Within a prospective clinical trial it was examined, if HZI fulfilled these demands.

METHODS

HZI is an anterior doublerod system with a two screw per vertebral body fixation. The longitudinal components consist of a threaded VDS-rod and a solid rod. 12 consecutive patients with idiopathic scoliosis and curves ranging from 36 degrees to 77 degrees were treated with HZI.

RESULTS

Correction of the frontal plane averaged 75% and 73.8% postoperatively and at follow-up, respectively. Derotation averaged 49.3%. Thoracolumbar kyphosis was present in four patients and always completely corrected. Implant related complications were not noted. All patients were treated without any additional external immobilisation.

CONCLUSION

The aim of improvement of VDS in terms of primary stability and control or improvement of the sagittal plane was completely achieved.