Treatment of ureteral stones by extracorporeal shock wave lithotripsy: with ureteral catheter or in situ?

The Dornier Compact Delta lithotripter: the first 150 ureteral calculi

BACKGROUND AND PURPOSE

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.

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Push and smash increases success rates in treatment of ureteric calculi by ESWL

During a 3-year period 105 patients underwent attempted retrograde manipulation for ureteric calculi into the renal pelvis prior to extracorporeal shock wave lithotripsy (ESWL). The success rate of this group was compared to 93 patients receiving ESWL of ureteric calculi in situ. The method of retrograde manipulation was recorded prospectively. Retrograde flushing with a 5 F Tiemann ureteral catheter was performed after coating the proximal ureter and renal pelvis with a mixture of saline and lidocaine gel. Success rate of calculi push was 91.4%. Mean number of ESWL treatments in this group of patients was 1.4, compared to 2.1 in patients with in situ treatment. Reposition of ureteric calculi prior to ESWL treatment increases successful initial treatment and can be performed easily.

Electrohydraulic lithotripsy of upper ureteral calculi with semirigid ureteroscope

Forty-three patients with single ureteral calculi located above the pelvic brim were treated by electrohydraulic lithotripsy (EHL) using a semirigid mini-ureteroscope. Of the 43 calculi, 36 (84%) were fragmented in one procedure. Six calculi (14%) were pushed back to the renal pelvis and treated successfully by complementary extracorporeal shockwave lithotripsy (SWL). The total success rate of ureteroscopic manipulation thus was 98%. The operation time (mean 26.4 minutes) and postoperative hospital stay (mean 2.53 days) were relatively short. Complications were limited to four (9%) minor perforations of the ureter managed by internal stenting. Among these patients with complications, there were no significant ureteral strictures noted on excretory urography or ureteroscopic examination 1 to 3 months after ureterolithotripsy. The costs of ureteroscopy with EHL are lower than that of SWL or ureteroscopic lasertripsy. The total fees for ureteroscopy with EHL are about two thirds those for SWL in Taiwan. Despite the longer learning curve required for ureteroscopy, ureteroscopy associated with EHL is a cost-effective alternative for the treatment of upper ureteral calculi, especially when SWL is not readily available.

Experimental study of Wallstent self-expandable metal stent in ureteral implantation

In regard to the risk of stent obstruction, there are persistent controversies concerning the use of the Wallstent self-expandable metal stents in the ureter. Only a few clinical trials have been published to date, and, from a technical point of view, no success predictors have been identified. In an experimental study using a pig model, we have shown that neither the length of the stent (5 or 10 cm) nor an initial 1-month intubation had any influence on the outcome of the stents. Among the eight implantations studied (four 5-cm and four 10-cm stents), only one 5-cm stent was perfectly patent at 35 days. In all the remaining stents, after 35 or 90 days, constant failure was related to distal narrowing at the edge of the stent, with no difference between the 5- and 10-cm stents or between the intubated and the nonintubated stents. This distal narrowing, probably attributable to a functional discrepancy between an adynamic stented ureter and a normal underlying ureter, demands extreme caution in human applications when the ureter is normally peristaltic.