Extracorporeal piezoelectric shockwave lithotripsy of ureteral stones: are second-generation lithotripters obsolete?

BACKGROUND

The role of extracorporeal shockwave lithotripsy (SWL) for ureteral calculi is still being debated. We evaluated our results in a large series to clarify the role of this modality.

PATIENTS AND METHODS

A total of 478 patients with solitary ureteral stones were treated by in situ piezoelectric extracorporeal shockwave lithotripsy (SWL) using a Wolf Piezolith 2300 ultrasound-guided lithotripter. Two hundred fifty stones (52.3%) were located in the upper ureter and 228 (47.7%) in the distal ureter. Seventy of the upper ureteral stones were located in the ureteropelvic junction and 180 in the lumbar ureter. The diameter of the stones ranged from 5 to 30 mm. Four hundred sixty-seven patients were followed up for a mean of 4 months.

RESULTS

Four hundred forty patients (94.2%) were stone free after in situ SWL alone. Complete removal of all stone fragments was achieved in 95.4% of the 216 patients with calculi of 5 to 10 mm in diameter, in 94.3% of the 229 with stones of 11 to 20 mm, and in 81.8% of the 22 with calculi of 21 to 30 mm. In situ treatment completely removed 61 of 69 ureteropelvic junction stones (88.4%), 166 of 175 lumbar stones (94.8%), and 213 of 223 distal ureteral stones (95.5%). In situ treatment failed in 27 stones (5.8%). After 4 months, 12 stone fragments and 15 unfragmented stones persisted despite retreatments and required endoscopic procedures. The mean number of sessions and shockwaves per patient was 1.8 and 4884, respectively. Morbidity was low. Renal colic in 57 patients (11.9%) was managed successfully by analgesics. In 36 patients, stone fragments obstructed the ureter; in 28 of these 36 (78%), the obstruction was resolved and the patients were stone free after in situ retreatments alone. All these results were achieved on an outpatient basis without sedation or local or general anesthesia.

CONCLUSION

Piezoelectric SWL is an effective and noninvasive method for eliminating ureteral stones. Second-generation ultrasound-guided lithotripters are not yet obsolete.