[Prognostic parameters in extracorporeal lithotripsy].

Extracorporeal lithotripsy consists of applying shock waves (electrohydraulic and piezoelectric) from outside the human body, which pass through the body tissues without damaging them breaking down the urinary calculi into particles which can then be automatically expulsed through the excretory tract. The object of this study is to analysis some of the important parameters which affect the success of the extracorporeal lithotripsy. These factors are as follows: 1) type of shock wave: electrohydraulic or piezoelectric, their action mechanism, methods of fragmenting the urolites; 2) the chemical composition of the calculi and its consequential resistance to the fragmented shock waves; 3) Patency, tone and peristalsis of the intra and extrarenal excretory tract for expulsing the urolite particles; 4) general conditions of the urinary apparatus. From the interaction of these 4 variables arise different clinical situations which must be evaluated before operating in order to develop the proper therapeutic subscription for a renal-urethral lithiasis. The current therapeutic procedures for renal-urethral lithiasis are as follows: electrohydraulic and piezoelectric extracorporeal lithotripsy; electrohydraulic waves or ultrasound percutaneous litholapaxy; operative urethroscope; traditional surgery; chemolysis.