OBJECTIVE: To evaluate the time to stone-free status after shock wave lithotripsy (SWL) for ureteral stones.
METHODS: Medical records of 387 patients with ureteral stones who have been treated were retrospectively reviewed. Exclusion criteria for this analysis included nonopaque stones, prior ureteric surgery, multiple ureteral stones, anomalous kidneys or ureters, hydroureteronephrosis, infravesical obstruction, nonfunctioning kidney, inadequate follow-up, and treatment with calcium-channel blockers and alpha blockers. Ninety or 120 shocks per minute at suggested maximum energy for safety were applied. Patients were revisited periodically and stone-free status was accepted as success. The data were analyzed according to stone localizations; size (5-10 mm [group 1], 11-15 mm [group 2], and ≥16 mm [group 3]); and number of SWL sessions.
RESULTS: The initial stone locations were: upper ureter in 23%, middle ureter in 17.9%, and distal ureter in 59% of the patients. The average stone diameter was 10.1 mm (range, 5-23). The SWL sessions varied between 1 and 4 (mean, 1.3). Of the 117 patients 109 (93.1%) were stone free 20 days after the first session of SWL. The mean time to achieve stone-free status was 4.6 days. Group 1 had the quickest stone clearance time as expected (mean, 2.2 days [range, 1-3]). Groups 2 and 3 had longer times at 7.7 days (range, 3-18) and 12.2 days (range, 11-37), respectively.
CONCLUSIONS: SWL appears as a quick and effective treatment modality for ureteral stones. However, high-burden ureteral stones (>16 mm) have considerably long periods of clearance and therefore appear to be unsuitable for SWL treatment.
Copyright © 2011 Elsevier Inc. All rights reserved.
Urology. 2011 Jul;78(1):26-30. doi: 10.1016/j.urology.2010.10.060. Epub 2011 Feb 18
PMID:21333330 [PubMed - as supplied by publisher]
A high rate of exclusion due to either a few rare and some frequently met patient conditions is the cause why only 107 of 387 patients with ureteric stones treated with ESWL could be evaluated in this retrospective study.
This selection might be one of the reasons for the high success rate for a single session ESWL therapy. The respective figures vary a little bit in the paper:” Ninety of 117 patients required only 1 session to achieve stone-free status.” That would be 77%. “Most of the patients (80.3%) completed the treatment with only 1 session and with 100% success rate.” “Of the 117 patients, 109 (93.1%) were stone-free 20 days after the first session of SWL.”
Essentially the results were very good and the authors stressed that they treated according to the manufacturers recommendations concerning the maximum energy and the number of shots.