[Endoscopic techniques in the treatment of calculi in the upper urinary tract]

There is no single method for treating all urinary calculi. Because of the non-invasive nature of extracorporeal shock wave lithotripsy this method has been embraced by patients and doctors alike. However, some 15-20% of the patients require more invasive methods like percutaneous nephrolithotripsy and ureteroscopy to get rid of their stones. Percutaneous nephrolithotomy is best employed for large stones (> 2.5 cm diameter), staghorn calculi, renal anatomic abnormalities and hard stones and in patients whose anatomy precludes the use of lithotriptor. With the advent of ureteroscopes of much smaller diameter, endourologic intervention has become a steadily safer and more effective means of treating stones in the ureter. With ureteroscopic techniques success rates up to 97% have been reported. A large number of stones have to be fragmented before retrieval. Both ultrasonic and electrohydraulic lithotripsy have been available since the introduction of ureteroscopic techniques. The devices, however, are limited by their size (in the case of ultrasound) and for safety reasons (in the case of electrohydraulic lithotripsy). Laser lithotripsy has received attention as an alternative method of fragmentation which also can be applied with flexible ureteroscopes.