Shockwave Lithotripsy Preferred to Ureteroscopy for Single, Distal Ureteric Stones

Laurie Barclay, MD

November 19, 2010

November 19, 2010 — Extracorporeal shockwave lithotripsy (ESWL) was better than ureteroscopy (URS) as first-line therapy for patients with single, distal ureteric stones, according to the results of a prospective, randomized study reported in the December issue of BJUI.

"ESWL and URS are both accepted treatments for distal ureteric stones, but there is a lot of discussion about which surgical technique should be used as a first-line strategy for this condition," senior author Vincenzo Mirone, MD, from University Federico II of Naples, in Italy, said in a news release. "Approximately one in three adults with kidney stones will have a distal ureteric stone at some point in their lives. Most stones with a diameter of up to 0.5cm will be expelled spontaneously when the patient urinates without requiring any active intervention. For larger stones that get stuck in the ureter, spontaneous expulsion is very difficult and requires active intervention."

The study goal was to compare ESWL and URS as first-line therapy in 273 patients with single, monolateral, radiopaque, distal ureteric stones 0.5 to 1.5 cm in size.

Patients were randomly assigned to undergo ESWL (n = 137) with an electromagnetic Modulith SLX lithotripter (Storz Medical) or URS (n = 136) with a semi-rigid ureteroscope. Most (98%) of ESWL treatments were done on outpatients, and none of the patients needed anesthesia or sedation, whereas 96% of URS treatments were done on inpatients, with 22% of patients receiving general anesthesia, 66% receiving local anesthesia, and 12% receiving sedation only.

Both groups were similar in terms of clinical factors, including average age (50 years) and male:female ratio (~1:1). Outcomes were overall stone-free rates (SFRs), rates of repeat treatment, need for additional procedures, and complication rates. Subgroups of patients with stone size of 1 cm or smaller and larger than 1 cm were also analyzed separately.

In the overall ESWL group. SFR was 92.70%, retreatment rate was 44.88%, auxiliary procedure rate was 11.02%, and complication rate was 15.32%. One ESWL session was sufficient in 55% of patients, whereas 31% needed 2 sessions and 13% needed 3 sessions. In the overall URS group, SFR was 94.85%, retreatment rate was 7.75%, auxiliary procedure rate was 18.60%, and complication rate was 19.11%.

Among patients treated with ESWL, those with stones larger than 1 cm had significantly higher need for retreatments and for additional procedures and had higher complication rates. In contrast, for patients with stones 1 cm or smaller, those treated with ESWL had significantly lower rates of retreatment, auxiliary procedures, and complications than those treated with URS.

"Statistical analysis showed no significant differences in overall [SFR], treatment duration, complications and the need for auxiliary procedures," Dr. Mirone said. "However, there were clear differences in both groups when we divided them into patients with stones of up to 1cm and stones of over 1cm.... These results clearly indicate that ESWL should be the first choice for patients with stones of 1cm and under and URS should be the first choice for patients with stones exceeding 1cm."

The study authors have disclosed no relevant financial relationships.

BJUI. 2010;106:1748-1752.

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