Ureteral lithiasis: in situ piezoelectric versus in situ spark gap lithotripsy. A randomized study

In situ extracorporeal lithotripsy (EL) is the treatment of choice for ureteral lithiasis at our institution since the introduction of the painless lithotripters in clinical practice. The major objections to such clinical approach are: difficult ultrasound localization of ureteral calculi (if an ultrasound-guided lithotripter is used); lower energy of the painless piezoelectric compared to the spark gap system. To evaluate the efficacy of in situ EL of ureteral stones and to compare two different lithotripters (the spark gap fluoroscopically-guided Dornier HM3 versus the piezoelectric ultrasound-guided Wolf Piezolith 2300), we conducted a prospective randomized study.

70 patients were randomly divided into two groups according to the following inclusion criteria: radiopaque stones of lumbar or prevesical tract (iliac and pelvic stones were excluded); stones with largest diameter not more than 2 cm.

The evaluation of the treatment was done by plain film (KUB) at 24 and 72 hrs and by ultrasound at 48 hrs to assess stone fragmentation using migration of the fragments more distally into the ureter as criteria for success. The results were comparable: 76.6% for extracorporeal piezoelectric lithotripsy (EPL) and 74% for extracorporeal shock wave lithotripsy (ESWL). Better results were observed in both groups for the prevesical stones. The focussing time required was also comparable.