Purpose: We describe a more efficient solution for calcium magnesium stones, an irrigation technique devised by us, and the indications for and results of our 20-year experience with direct renal or ureteral chemolysis.
Materials and methods: Renal and ureteral perfusion is performed with 2 coaxial catheters (where the interspace is 1-way circulation), a normal ureteral catheter to a nephrostomy tube or, if the ureter is impractical, a nephrostomy tube after inserting it in a thin catheter achieving coaxial circulation. The perfusion operates by gravity with continuous flow maintaining a negative pressure in the cavities and keeping the circuits sealed during treatment. All equipment is mounted on a mobile support which the patient can take anywhere in the hospital.
Results: During the last 20 years 8 cystine stones and 20 "difficult" stones have been completely dissolved and the volume of 39 staghorn struvite stones has been reduced an average of up to 80% before 1 or 2 final lithotripsy sessions without significant side effects. Small fragments remained in the inferior calices in only 2 cases.
Conclusions: Chemolysis is useful for eliminating cystine stones as well as for cases in which lithotripsy or endourology is considered difficult or risky. Furthermore, chemolysis proved to be a useful method for reducing staghorn stones before performing lithotripsy.