The Dornier Compact Delta lithotripter: the first 150 ureteral calculi

Shockwave lithotripsy (SWL) is the least invasive treatment for ureteral calculi and is the best accepted by patients and clinicians. This prospective study was performed to evaluate the results of SWL for all ureteral calculi.

Between April 1999 and May 2000, there were 150 SWL treatments for ureteral calculi at our center. All patients who completed treatment (24 females, 126 males with an average age of 54 +/- 14 years) were entered in the study and were assessed at 1 and 3 months with a plain film of the kidneys, ureters, and bladder and an ultrasound scan or intravenous urogram if clinically indicated. The outcome has been analyzed according to stone size, location (lower ureter [LU], midureter [MU], and upper ureter [UU], number of treatments per stone, number of shocks per stone, and stone-free rate (SFR). The analgesia requirements during each treatment and complications have also been analyzed.

The SFR in the UU was 77% at 1 month and 85% at 3 months. The SFR in the MU was 74% at both 1 and 3 months. The SFR in the LU was 65% at 1 month and 74% at 3 months. Overall, the SFR for all calculi was 72% at 1 month and 79% at 3 months. Ureteroscopic extraction was necessary in 19% of the patients and conservative management for the remaining asymptomatic fragments, which were 2 mm or smaller. All of these asymptomatic fragments were seen to have passed spontaneously on follow-up imaging studies. Ureteral stents were not placed routinely prior to SWL, but there were 32 calculi (21%) for which stents had been placed prior to SWL: 29 (19%) in the UU, 3 (2%) in the MU, and 0 in LU. There was no difference in the SFR or ureteroscopy rate in UU calculi treated with or without stents and no difference in the number of treatments needed to achieve these SFRs. The efficiency quotient for the UU was 55%, 45% for the MU, and 45% for the LU. Oral analgesia was given routinely; however, additional intravenous analgesia was necessary in 24% of treatments. No serious complications were seen.

The Dornier Compact Delta lithotripter provides an effective noninvasive treatment for ureteral calculi that is achieved with minimal anesthesia and a low complication rate. Placement of ureteral stents prior to SWL does not enhance the SFR or obviate intervention if SWL fails. We recommend a low threshold for ureteroscopic treatment if significant progress is not made in fragmenting the stone with SWL.