[The use of laser for percutaneous nephrolithotomy]. / Aplicación del láser en nefrolitotomía percutánea.

ABSTRACT

OBJECTIVES: The non negligible number of residual stones after extracorporeal lithotripsy is leading to a revision of the indications of percutaneous nephrolithotomy (PCNL). The laser, managed with flexible nephroscopes, plays an important role in this field. Pulsed Nd YAG, dye and alexandrite lasers have given way to the holmiumyag laser in the endourological treatment of urinary lithiasis. METHODS: More than one lithotripter are often required for percutaneous nephrolithotomy of great volume stones, and ballistic and electrokinetic lithotripters are generally preferred due to their high performance. The best indications for Holmium laser is the treatment of caliceal stones far from the pelvis, only accessible through flexible nephroscopes. Midi and minipercs, renal lithiasis in children and some earthy calculi, of low consistency, are also good indications for it. Depending on the anatomical characteristics of the kidney and localization, number, size and hardness of the stone 200, 365, or 500 nanometer fibers may be employed. Due to the fact that the laser drills a hole in the stone like if it is a thermal barrier, it may break in different ways applying the quartz fiber in between the layers, drilling all the interior before breaking the surface, or drilling multiple points to weaken it and creating broad fracture lines. To accelerate the breaking process one can choose to use larger fibers or to modify the settings of the equipment increasing the potency, although this has some potential risk for the kidney. RESULTS: The theoretical 100% of good results is reduced due to multiple technical and anatomical factors size, number, localization, and hardness of the stone, as well as the possibility of reaching and seeing the calculus and being able to place the tip of the fiber against it. CONCLUSIONS: Although the holmium laser develops on excellent role at the time of avoiding leaving residual calculi or diminishing the number of them, sometimes the electrohydraulic lithotripsy is more effective.