Salem HK et al, 2013: Slow Delivery Rate versus Rapid Delivery Rate Shock Wave Lithotripsy (SWL) for Pediatric Renal Urolithiasis: a Prospective Randomized Study
Salem HK, Fathy H, El Fayoumy H, Ali H, Ghonium A, Mohseen MA, Hegazy AE
Urology Department, Faculty of Medicine, Cairo University, Giza, Egypt
PURPOSE: To compare the slow versus the fast shock waves frequency rates in disintegration of pediatric renal stones less than 20mm.
MATERIAL AND METHODS: Our study included sixty children with solitary radio opaque renal stone 10-20 mm in size treated by SWL; they were prospectively randomized into two groups. Group I included 30 patients subjected to 80 SW/min rate and Group II included 30 patients subjected to 120 SW/min rate. The two groups were compared in terms of treatment success, anesthesia time, secondary procedures, and efficiency quotient (EQ).
RESULTS: Stone clearance rate was significantly more in group I (90%) than group II (73.3%) (P= 0.025). In group I, 18 patients (60%) rendered stone free after one session, 8 patients needed 2 sessions, and only one patient needed 3 sessions while three patients failed SWL. In group II, 8 patients (26.6%), 10 patients (33.3%), and 4 patients (13.3%) needed one, two, and three sessions respectively to be stone free. The general anesthesia mean time was significantly longer in group I (P= 0.041). Postoperatively, six patients suffered from low grade fever (Clavien II ); two in group I and four in group II. The secondary procedures (PCNL or repeat SWL) were significantly more in group II (P= 0.005). The predominant stone analysis was ca oxalate dihydrate in either group. EQ was 0.5869 and 0.3437 for group I and group II respectively (P=0.0247).
CONCLUSION: In pediatric renal stones, slow delivery rates of SWL have better results on stone clearance than fast delivery rates.
J Urol. 2013 Nov 18. pii: S0022-5347(13)05981-8. doi: 10.1016/j.juro.2013.11.028. [Epub ahead of print]
PMID:24262496[PubMed - as supplied by publisher]
In accordance with numerous studies in adults it was shown in this randomized study on paediatric patients that shockwaves delivered at a slow rate (80 sw/min) resulted in a better stone disintegration than a high frequency (120 sw/min). The re-treatment rate was also significantly lower in the low-frequency group. The optimal shockwave frequency remains to be determined, but it stands to reason that a frequency of 120sw/min definitely should be abandoned - in children as well as in adults. Actually this should have been the recommended routine since several years and there should be a warning for using this setting on lithotripters particularly since it has been demonstrated that a high shockwave frequency might increase the risk of tissue damage.