**9. Recent trends in extracorporeal shockwave lithotripsy (ESWL)**

The large number of patient treated by SWL in the past 25 years gives an important informa‐ tion about indications, contraindications, adverse effects of the procedures and the required development to improve the techniques of SWL for better treatment and less side effects [31]. Krambeck et al. [32] found that HTN incidence was significantly correlated with bilateral pro‐ cedures done by using a Dornier HM3 lithotripter, while DM was correlated with shock wave number and frequency. The author postulate that occurrence of DM and HTN may be due to unobserved microtrauma on the pancreas and the kidney. Chew et al. [33] compared the inci‐ dence of DM and HTN in patient treated with an unmodified lithotripter HM3 (USWL) and second‐generation modified HM3 lithotripter (MSWL); they found that there was no association between lithotripter and development of either DM or HTN in multivariate analysis and they suggest that the prevalence of DM and HTN in patient with renal stones is due to the presence of metabolic syndrome. Where there is increasing evidence, the patient with renal stones get HTN and DM and vice versa through this syndrome. Lee et al. [34] introduced that SWL treat‐ ment at frequency of 60 shocks/min gave better outcome compared with SWL at 120 shocks/ min. On the other hand, pretreatment did not impact renal injury. Salem et al. compared slow and fast shock wave frequency, delivery rates in disintegrating pediatric renal stones smaller than 20 mm and the impact on stone clearance. Terms of comparison include treatment suc‐ cess, anesthesia time, secondary procedures, cost and efficiency quotient. They found that slow delivery rate of SWL has better stone clearance results than fast delivery rate [5]. Mazzucchi et al. [35] found no significant differences in the stone‐free rate and complications develop‐ ment by reducing the total number of impulses from 4000 to 3000 and the frequency from 90 to 60 impulses/min. Vakalopoulos [36] developed a mathematical model to predict ESWL outcomes where predictive equations can be generated for different lithotripters. Wiesenthal et al. [37] developed a remarkable nomogram to predict the outcomes of renal and ureteral stone SWL treatment dependent on patient and stone factors. The risk of SWL failure is significantly related to increase radio density both in vivo and in vitro; cysteine, calcium oxalate, monohy‐ drate and brushite stones are less liable to be treated by SWL [38, 39]. Salem et al. [40] conducted a prospective randomized trial over 200 patients comparing the SWL and semi rigid ureteros‐ copy for management of proximal ureteral calculi. He found that URS has higher free stone rate than SWL but more adverse effects so SWL should be the first‐line treatment for proximal ureteral calculi of size < 1 cm. The introduction of second‐ and third‐generation lithotripter not improves the stone‐free rate or decreases the number of operations needed, but they have less anesthesia and minimal tissue injury [41, 42].
