EVOLUTION OF PRETREATMENT STENTING AND LOCAL-ANESTHESIA FOR EXTRACORPOREAL SHOCK-WAVE LITHOTRIPSY AT A SINGLE UNIVERSITY CENTER

Evolution of the extracorporeal shock wave lithotripsy technique involves not just second generation technology but operator innovations and experience. Retrospective analysis of the first 512 treatments at a university medical stone unit using the Dornier HM3 lithotriptor was compared to 3 intervals of 100 consecutive treatments during the next 2-year period (1985 to 1987). Patient referral and selection as well as treatment techniques and rates of endourological interventions were analyzed. Patient demographics, stone types and retreatment rates remained constant during 2,500 treatments. However, the use of local anesthesia and internal ureteral stents became increasingly common. Of the 1987 cohort 29% were treated with the patient under local anesthesia, and 23 of the 44 with a stent (52%) received internal ureteral stents. Other treatment trends identified during the study period included increasing number of large (greater than 2 cm.) and multiple stones treated; increasing use of internal and external ureteral catheters before treatment, fewer stents for small, mobile renal calculi and decreasing length of hospital stay (2.7 to 2.1 days) with increasing use of stents before lithotripsy. The increasing average number of shock waves per treatment (1,382 versus 1,580) during the study period can be attributed to the larger proportion of patients with high stone burdens and the impact of an increased number of operators with more varied criteria for endoscopy and treatment end point.