Extracorporeal shock-wave lithotripsy success rate and complications: initial experience at Sultan Qaboos university hospital

To assess the efficacy and safety of extracorporeal shock wave lithotripsy with Modularis Vario Siemens in the management of patients with renal and ureteral stones. Between 2007 and 2009, 225 outpatients were treated with Siemens Modularis Vario lithotripter at Sultan Qaboos University Hospital. Stone size, location, total number of shockwaves, stone-free rate, complications and adjunctive interventions were investigated. Chi-Square and Logistic Regression analyses were used, with p<0.05 set as the level of significance. Of the 225 initial consecutive patients who underwent extracorporeal shock wave lithotripsy, 192 [85%] had renal stones and 33 [15%] had ureteric stones. The mean +/- SD stone size was 11.3 +/- 4.5 mm, while the mean age of the patients was 39.9 +/- 12.8 years with 68.5% males. The mean renal stone size was 11.6 +/- 4.7 mm; a mean of 1.3 sessions was required. The mean ureteric stone size was 9.9 +/- 3 mm; and a mean of 1.3 sessions was required. Treatment success [defined as complete clearance of ureteric stones, stone-free or clinically insignificant residual fragments of <4 mm for renal stones] was 74% for renal stones and 88% for ureteric stones. Additional extracorporeal shock wave lithotripsy and ureteroscopy were the most adjunctive procedures used for stone clearance. Complications occurred in 74 patients [38.5%] with renal stones and 13 patients [39.4%] with uretetric stones. The most common complication was loin pain [experienced by 16.7% with renal stones and 21% with ureteric stones]. Severe renal colic mandating admission occurred in 2% of patients with renal stones and 6% of patients with ureteric stones. In patients with renal stone, steinstrasse occurred in 3.6% and infection post extracorporeal shock wave lithotripsy in 0.5%. Using Multivariate Logistic Regression analysis, factors found to have significant effect on complete stone clearance were serum creatinine [p=0.004] and the number of shockwaves [p=0.021]. Siemens Modularis Vario lithotripter is a safe and effective tool for treating renal and ureteric stones