Novel electromagnetic lithotriptor for upper tract stones with and without a ureteral stent

We compared the treatment efficacy and safety of the novel Lithoskop electromagnetic extracorporeal shock wave lithotriptor for upper urinary tract stones with and without prior ureteral stent placement.

A total of 665 consecutive patients harboring single renal or ureteral stones underwent shock wave lithotripsy between August 2006 and July 2008. In 75 and 46 patients with renal and ureteral stones, respectively, stents were placed before the first shock wave lithotripsy session. Treatment outcome was assessed in relation to stent placement. All data were derived from a prospectively maintained database.

The mean size of nonstented vs stented renal and ureteral stones was 8.6 vs 12.5 mm (p <0.0001) and 7.1 vs 7.3 mm (p = 0.6), respectively. The stone-free rate in nonstented vs stented renal and ureteral stone cases was 76.3% vs 77.3% and 91.4% vs 93.5%, respectively (each p >0.99). The total energy applied per stone was 110 +/- 83 vs 150 +/- 89 J (p <0.0001) and 183 +/- 131 vs 209 +/- 125 J (p = 0.1), respectively. Auxiliary measures were required after shock wave lithotripsy for renal and ureteral stones in 5.4% and 10.8% of nonstented, and in 1.3% and 4.3% of stented cases, respectively. No complications were detected in stented renal and ureteral stone cases compared to 2.9% and 6.9% in nonstented cases, respectively.

A high success rate and a low complication rate were achieved in renal and ureteral stone cases with and without prior ureteral stent placement. Total energy needed to achieve a stone-free state did not differ between stented and nonstented ureteral cases, suggesting the absence of a significant influence of the stent. Overall stents decreased complications necessitating hospitalization and auxiliary invasive measures.