Goren MR et al, 2016: Ultrasound-Guided Shockwave Lithotripsy Reduces Radiation Exposure and Has Better Outcomes for Pediatric Cystine Stones.
Goren MR, Goren V, Ozer C.
Department of Urology, Baskent University Adana Dr. Turgut Noyan Medical and Research Center, Adana, Turkey.
Abstract
BACKGROUND/AIMS/OBJECTIVES: To evaluate the outcomes and ionizing radiation (IR) exposure of children with cystine stones (CS) using different shockwave lithotripsy (SWL) guidance modalities.
METHODS: Data from pediatric patients with renal stones treated between January 2009 and August 2015 were retrospectively reviewed. Outcome results and IR exposure in patients undergoing fluoroscopy (FL)-guided SWL and ultrasonography (US)-guided SWL were compared. First-time stone formers and those treated with SWL and with complete follow-up data, including post-treatment stone analysis confirming CS were included.
RESULTS: Forty-four patients (16 girls and 28 boys) met the inclusion criteria. Results of SWL performedin 51 kidneys were analyzed. After the SWL, 41 (80.4%) of 51 kidneys were stone free, and 10 (19.6%) had clinically insignificant residual fragments (≤3 mm) or unfragmented stones. The success rates differed between patients in Group-FL (60%) and Group-US (93.5%) (p = 0.008). Single-session success rates were higher, and prospects of retreatment were lower in Group-US (p = 0.000 and p = 0.002, respectively). In addition, overall complications were significantly lower in Group-US (p = 0.042). Overall IR exposure was higher in Group-FL (p = 0.013).
CONCLUSIONS: US-guided SWL is more effective for pediatric CS and should be considered a preferred treatment to reduce IR doses in children.
Urol Int. 2016 Apr 30. [Epub ahead of print]
Comments 1
Radiation exposure during all kinds of stone removal is an issue that always need due attention. The problem is particularly important for children as well as in all other patients in whom recurrent stone formation and repeated treatment sessions can be expected.
One very specific group in this regard is children with cystine stone disease. They have early start of stone formation and expected need of frequent future stone removal.
In this retrospective analysis of 51 renal units with cystine stones in children (mean age 2.9 years) SWL was carried out in 20 with fluoroscopy (FL) and in 31 with ultrasound (US) localization.
Interestingly the success rate was significantly higher in the US-group than in the FL-group, despite a lower re-treatment rate in the former children.
The authors do not provide a definite explanation for the difference between the two groups, but is seems likely that with FL identification proper focusing of the stone with intermittent pulsed imaging might have been less accurate than with US. In contrast a much higher hit-rate have been achieved with continuous US, particularly since cystine stones have a low radio-density.
It is correctly stated by the authors that US is “generally underused” and it seems reasonable to spend sufficient time by training US-localization of stones. To achieve that goal it also is desirable to get more user-friendly US-localization systems in the lithotripters.
It is my personal opinion that steps to reduce radiation are extremely important in the further development of the SWL-technology.