[The methodology of percutaneous nephrostomy. The two-step technique].

A new two-step technique for percutaneous nephrostomy with a newly designed nephrostomy set is described. The technique combines the advantages of the a direct introducing method (one-step nephrostomy) with an introducing trocar and the "three-step" technique with an initial puncture by a needle and insertion of a rigid guide wire. Evaluation of the different techniques in 195 patients revealed no disadvantage of the new technique compared with the three-step technique.