In vitro study concerning the efficiency of the frequency-doubled double-pulse Neodymium:YAG laser (FREDDY) for lithotripsy of calculi in the urinary tract.

BACKGROUND AND

OBJECTIVES

In a preclinical study we have tested both in vitro and in vivo, a new type of pulsed solid-state laser system that has not been applied in urology so far and has been developed for optimized intracorporal lithotripsy of biliary, salivary, and urinary calculi.

STUDY DESIGN/MATERIALS AND

METHODS

Sixty one calculi from the human urinary tract were split in vitro into fragments with a remaining particle size of </= 2 mm using the prototype of a short-pulsed passively Q-switched and frequency-doubled double-pulse Neodymium:YAG laser. In a supplementary animal test, the bladder mucosa of five rabbits was directly exposed to a highly rated laser beam to be able to assess the tissue lesion potential of the system.

RESULTS

All the 61 urinary calculi with different composition were successfully split in vitro within a short period of time (2.5 +/- 4.6 minutes). During histopathologic examination of the exposed bladder walls of the rabbits only a small tissue lesion potential with urothelium changes exclusively at the surface was ascertained.

CONCLUSION

The high degree of fragmentation efficiency, the purchase and maintenance costs, which due to its design are substantially lower in comparison to other laser lithotriptors, and the high degree of safety during application make this new laser a real alternative not only to the present laser lithotripsy systems but also to common ballistic lithotriptors.