Extracorporeal shock wave lithotripsy in children: experience using a mpl-9000 lithotriptor

Our objectives were to assess the value of extracorporeal shock wave lithotripsy (ESWL) in treating pediatric urolithiasis, and to determine the factors that may affect treatment success. Between January 1993 and August 2002, 129 children with upper urinary tract calculi (134 renoureteral units) were treated using a Dornier MPL-9000 lithotriptor. The series consisted of 77 boys and 52 girls with an age range from 20 months to 14 years (average age: 8.7 years). All ESWL procedures took place under general anaesthesia or sedation with ketamin or fentanyl. Under ultrasonic or fluoroscopic guidance, children were treated with a maximum 2,550 shocks at an average of 19.5 kV. Success was defined as the lack of any visible stone fragments on post-treatment radiological evaluation. The patients were assessed 3 months after ESWL treatment and the results were compared using χ²-tests to detect factors that might be associated with treatment success. There were 105 renal, 20 ureteral, four bilateral renal and one unilateral renal plus contralateral ureteral calculi. The mean sizes were 15.7 mm for pelvic, 17.8 mm for renal and 10.2 mm for ureteral stones. One or two lithotripsy sessions were sufficient in most cases (71.6%). In 15 (11.6%) patients, double J stents introduced before lithotripsy were left indwelling until all stone fragments were voided. Overall success rates were 89.5% for pelvic, 85.5% for renal and 75% for ureteral stones. Complications such as urinary tract infection, Steinstrasse and small subcapsular hematoma occurred in 19 (14.7%) patients. The only significant factor associated with the stone-free rate was the diameter of the stone (P=0.022). This study confirmed that the stone-free rate is significantly influenced by stone size. Because children with stone disease are at risk for a longer period than adults, their cumulative likelihood of stone recurrences may be higher. Thus, we agree with other authorities that minimally invasive treatment, such as ESWL, is mandatory in children with urolithiasis.