J Endourology 2009; 23(Suppl 1): A165-A166.

Creation of a fluid chamber with the Accordion device increases fragmentation during ureteral ESWL: in vitro and ex vivo results.

JV Di Trolio, PN Ciccone, MD LaSalle, R Bhalla

Introduction:  A fluid-filled chamber is postulated to increase cavitation during ESWL, which increases stone fragmentation.  The objective of this study was to measure fragmentation efficacy during use of a stone device that forms such a chamber.

Methods: In vitro model: stones (UltraCal-30) were advanced into an artificial ureter and placed in the focusing cup of a Modulith SLX (Storz Medical) filled with deionized water.  A single ESWL session (energy level 9 for 1000 shocks) was applied with either a 10 mm Accordion device (PercSys) distal to the stone or no device present in five replications.  Ex vivo model: stones were advanced within an explanted porcine ureter and placed upon the treatment head of a Compact Delta (Dornier), sandwiched between pouches of saline.  A clinical cycle of ESWL (total of 2400 shocks) was replicated three times each with either a 10 mm Accordion device immediately distal to the stone or no device present.  Fragmentation coefficient (FC) was determined as FC = 100(Weightinitial – Weightfollowing)/Weightinitial.  Significance was determined using Student’s t-Test.

Results: Mean FC following a single application was 63 with an Accordion device distal to the stone versus 47 without the device (p=0.04) in the in vitro model.  The sessions in excised ureters resulted in an FC of 33 with the device present versus only 9 without the device (p=0.008). 

Conclusion: Tenting tissue away from the stone surface by the Accordion device created a fluid interface in both simulated ureters and excised porcine ureters and significantly increased the fragmentation coefficient of ESWL.

90-1040- 01 rA