In patients with renal calculi, studies of new-generation lithotripters have not demonstrated equivalent stone-free rates to the early-generation HM3 spark-gap machine (Dornier MedTech Europe GmbH, Wessling, Germany); this finding might be caused by differences in patient selection between the HM3 and new-generation lithotripter studies. The early assessment of the HM3 lithotripter was in patients with previously untreated renal calculi.OBJECTIVE
To evaluate the efficacy of the Sonolith Vision (Technomed Medical Systems, Vaulx-en-Velin, France) fourth-generation lithotripter for the treatment of previously untreated renal calculi in patients with anatomically normal kidneys.DESIGN AND INTERVENTION
This study evaluated data collected between September 2004 and March 2006 from a prospective, single-institution database of patients with urinary stones treated with the Sonolith Vision lithotripter. Exclusion criteria were previous treatment failure, multiple treatment targets in the same kidney, diverticula, horseshoe kidney, solitary kidney, ureteric stones, age <18 years and follow-up duration <3 months. Before treatment, serum biochemistry and coagulation tests were performed,and a plain film of the kidney, ureter and bladder was obtained; patients with radio-opaque and radiolucent stones also underwent intravenous urography and renal ultrasonography, respectively. Extracorporeal shock wave lithotripsy (SWL) was performed by the same team of radiographers who collected the baseline data. Rectal diclofenac sodium 100 mg was administered for analgesia, and additional intravenous alfentanil was administered if required. A plain abdominal radiograph was taken immediately after, and 1 and 3 months after extracorporeal SWL; patients were followed-up until they were stone free or until additional procedures were required.OUTCOME MEASURES
The primary outcome measures were the stone-free rate, additional procedures required to render patients stone free, and the presence of residual stone fragments <4 mm in size. Secondary outcome measures included alfentanil administration and complications of treatment.RESULTS
In total, 309 patients with 373 renal calculi were eligible for inclusion. The mean patient age was 57.5 years, 67% of patients were male, and the mean follow-up period was 8 months. The initial fragmentation rate was 94%, and the overall stone-free rate 3 months after extracorporeal SWL was 75%. For stones <10 mm, 11-20 mm, and >20 mm in size, the stone-free rate was 77%, 69% and 50%, respectively. Stone location was not significantly associated with stone-free rate: for lower, upper and middle calyceal and renal pelvic calculi, the stone-free rates were 74%, 70%, 78.5% and 75%, respectively. Additional procedures were required in 7% of patients, and residual fragments <4 mm were detected in 9.6% of patients. Alfentanil was administered to 45% of patients, and treatment was abandoned in 1.6% of patients because of intolerable pain. No serious complications were reported.CONCLUSIONS
The Sonolith Vision lithotripter has low retreatment rates and a good safety profile; these results match the historical results obtained with the HM3 lithotripter, but patients can be treated as outpatients with the Sonolith Vision lithotripter, and receive minimal analgesia.