Pediatric extracorporeal shockwave lithotripsy: its efficiency at various locations in the upper tract

Abstract

Background: Several reports demonstrated the effectiveness of extracorporeal shockwave lithotripsy (SWL) in the management of pediatric upper tract urolithiasis. The majority of these studies used the stone-free rate as the main indicator for treatment success. Efficacy Quotient (EQ) is an important outcome measure because it not only takes into consideration the stone-free rate, but also includes other undesirable outcomes that increase patient morbidity and utilizes hospital resources. Nevertheless, very few studies reported on the EQ of pediatric SWL at various locations in the upper tract.

Methods: We retrospectively reviewed the records of 84 children (103 urinary calculi) who were treated with SWL in our institution between 1995 and 2005.

Results: There were 84 renal (pelvis, n = 27; upper calyx, n = 13; middle calyx, n = 8; lower calyx, n = 36) and 19 ureteric (upper third, n = 10; middle third, n = 5; lower third n = 4) stones. EQ for renal pelvic stones was 67% compared to 48% for caliceal stones (upper calyx: 52%, middle calyx: 46% and lower calyx: 47%). Overall, the EQ for renal stone was 54% and it was 59% for ureteric stones. This efficiency in the ureter was achieved at the expense of a higher number of shock waves delivered (3606 vs. 2592, P < 0.01). Overall, the stone-free rate was 82% (renal, 81%; ureteric calculi 84%). The only factor that affected the stone-free rate was the size of the stone (33% in stones >2 cm and 87% in stones <2 cm (P < 0.01). The overall retreatment rate was 41% (renal, 40% and ureteric 42%). However, the number of total treatments ranged from 1 to 5 sessions in renal stones and 1 to 2 sessions in ureteric stones. Auxiliary procedures were performed in 9 patients (stenting, n = 3; ureteroscopy, n = 4 and percutaneous nephrolithotomy, n = 2).

Conclusions: Pediatric SWL appears to be more efficient in the renal pelvic stones compared to caliceal stones. The efficiency of SWL in the ureter is achieved with a higher number of shock waves delivered. A discussion on the possible future modifications of the definition of EQ, especially in children, is also provided.