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A. Skolarikos, H. Mitsogiannis, C. Deliveliotisrates are associated with an increase in the proceduretime but with a decrease in the total number of shockwaves and lower power indices to fragment the stone, adecrease in re-treatment rates and a decrease in morbidityrate (10, 56-59).Progressive increase in lithotripter outputExperimental studies have shown that a progressiveincrease in lithotripter output voltage during SWL can producegreater stone fragmentation than protocols employinga constant or decreasing output voltage (60). However,clinical studies are lacking and urgently required.Twin-pulse technique and sequential twin-pulse deliveryBased on sufficient data on experimental studies, aprospective clinical study reported promising preliminaryresults using the twin-pulse technique, two identicalshockwave generator reflector units mounted at anangle and activated simultaneously, to fragment stones.Fifty patients with a radio-opaque single stone in thekidney or upper ureter were treated with the twin-headlithotripter and all rendered stone-free within 1 month,with minimal morbidity (61). Similarly, the delivery oftwo shockwaves, at carefully timed close intervals wasshown in experimental studies to improve stone fragmentation(62, 63). Clinical studies are required to confirmthese results.Percussion, diuresis and inversion (PDI) therapyManoeuvres to improve stone clearance after SWL forlower pole stones have been investigated. These haveincluded combinations of manual percussion, diuresisand inversion, referred to as PDI therapy. Randomizedcontrolled studies have shown better stone-free rates followingPDI therapy (64, 65). However, patients areunlikely to elect for SWL and time-consuming PDI sessionsif definitive treatment can be achieved in a singlevisit (66).Patient positionRecent papers are suggesting that treatment of patientswith ureteric stones in a prone or rotated positionachieved a better SFR, increased tolerance of shockwaves, and required a lower mean number of sessions(67, 68). However, in a recently published thoroughreview, authors felt that the literature on position fortreatment of proximal ureteric stones is not conclusive,and further well-designed studies with greater number ofpatients are required (66).Insertion of ureteral stents prior to SWLProspective randomized studies have underlined thatstone-free rates in stented patients did not differ fromthose in non-stented patients. These studies also indicatedthat ureteral stents should not be used in patientswith large renal calculi, since they did not reduce postSWL morbidity and they had side effects of their own(69-71).Expulsive therapy and SWLRecent literature suggests that a-blockers might increasestone clearance rates and reduce the symptom of uretericcolic and analgesic requirement following SWL. Theeffect is more remarkable in large stones which may continueto clear after 3 months if the drug is continued (72,73). Still, the level of evidence on this topic is low andfurther studies are needed (66).Chemolytic pre-treatment and after-treatmentIn vivo studies suggest that changing the urine chemicalenvironment prior to or at time of SWL we may be ableto improve stone fragmentation (74). Pharmacologictherapy, such as potassium citrate and thiazide diuretics,has been successfully used to facilitate clearance of fragmentspost-SWL (75, 76). Although a prospective studyhas shown increased clearance of calcium oxalate lowerpole calculi after SWL (75), larger studies incorporatingdifferent clinical scenarios are needed.DISCUSSIONBased on systematic review and metaanalysis of the publisheddata, European Association of Urology (EAU) andAmerican Urological Association (AUA) have publishedspecific guidelines on urolithiasis. These guidelinesclearly describe the current role of SWL in the treatmentof renal and proximal ureteral stones.According to the EAU guidelines SWL constitutes thefirst choice of treatment for radiopaque renal stones witha surface area ≤ 300mm 2 (≤ 20 mm). The recommendationis based on grade A and 1b level of evidence. Withthe same level of evidence percutaneous nephrolithotomyis recommended as the second line of treatment.Retrograde intrarenal surgery constitutes a third optionbased on grade C and 2a level of evidence data. For uricacid stones of same burden SWL lithotripsy is the secondoption following oral chemolysis and always in combinationwith the later (grade B, level of evidence 2a) (9).Based on the results of their meta-analysis the AUAguidelines group for the treatment of staghorn calculirecommended PNL as the first treatment option foreither complete or partial staghorn stones. PNL shouldbe the last alternate in the combination therapy. Shockwave lithotripsy monotherapy should not be used formost patients, especially when cystine stones are beingtreated; however, if it is undertaken adequate drainage ofthe treated renal unit should be established before treatment.SWL monotherapy is an optional treatment inpatients with stone burdens of < 500 mm 2 with normalcollecting-system anatomy and in children (24).The combined committee of AUA and EAU recommendedthat for patients with proximal ureteral stones requiringstone removal both SWL and URS should be discussedas initial treatment options for the majority ofcases [Based on review of the data and Panel consensus/Level1A-IV). Regardless of the availability of theequipment and physician experience, the patient shouldbe discussed about stone-free rates, anesthesia requirements,need for additional procedures, and associatedcomplications (standard option). Patients should beinformed that URS is associated with a better chance ofbecoming stone free with a single procedure, but hashigher complication rates. The meta-analysis demonstratedthat URS yields significantly greater stone-free60Archivio Italiano di Urologia e Andrologia 2010; 82, 1