[Lower calyx lithiasis: usefulness of the laser].

There is controversy yet about which is the best treatment modality for lithiasis of the lower calyx. The range of lithiasis clearance of the stones localized in the lower calyx will depend on various factors such as size, composition of the stone, type of lithotripter employed, type of urinary transport, and anatomy of the lower calyx. The role of flexible ureteroscopy in the treatment of intrarenal pathology has experimented a dramatic evolution, impulsed by the improvements in design of flexible ureterscopes, their degree of deflection, and better quality of image, in the great diversification of small calibre accessory instruments, and the use of the holmium laser for lithotripsy. Its development makes possible to offer it as a therapeutic option for the failures of extracorporeal lithotripsy in stones smaller than 1 cm and as first-line treatment for stones smaller than 1 cm in size if they are cystine stones or they have an attenuation level over 1000 HU; also in obese patients or those with coagulation problems.