[Comments on the contribution: initial results of surgical treatment of scoliosis with the Cotrel and Dubousset CD instruments by Ch. Hopf, H. H. Matthiass and J. Heine. Z. Orthop. 125 (1987) 347].

It really must be appreciated that in the above mentioned publication of Hopf, Heine and Matthiass the authors were brave enough-against normal habits-to publish their bad results. In demonstrating their cases they render the CD system a destructive rebuff. Not in one of their demonstrated cases they were able to show that there are convincing advantages of this surgery compared to other already wellknown and sufficiently proven methods. We still have to acknowledge the opinion of Nachemson (1986) that the CD method is yet in the experimental stage. The authors show in their selective cases how it should not be done. They sacrifice in favor of a primary stability functionally important segments of the spine cranially as well as caudally and thus mutilate young human beings to an irresponsible extent. Of course it is astonishing when the authors in spite of their actually crushing experiments with this system in summary arrive at positive results without reasons indeed. For example they comment positively on the attained derotation, although they had shown with their results that no derotation could be achieved at all. Remarks about diminishing the rib hump, which should after all be a result of a good derotation are missing. Exact measurements in CT scans of the apical vertebra, as demonstrated in an extraordinary way by Giehl, have not yet been made in Münster. Otherwise the authors would have clearly recognized that a derotation with resection of the discs is not possible using the CD method. The authors present the system-in spite of their very bad results-as a universal spinal system for correction and stabilization and at the same time they doubt the value and extent of anterior surgical methods according to Dwyer or Zielke, even though these methods have internationally shown how the optimal corrections have resulted in fewer mutilations by using shorter fusion areas on the spine provided that the surgeon knows how to use the instruments. We spine surgeons should always be aware that we can cause an irreversible condition on the spine of the human being with our spinal fusion operation this could have grave results for the patient for his whole life. No doubt, there are advantages in the CD method, but they rather result in better stability than in better corrections.(ABSTRACT TRUNCATED AT 400 WORDS)