Experimental study on dissolution of calcium oxalate calculi with Tris-ethylenediaminetetraacetic acid buffer and trypain

Objective To study the safety and efficiency of Tris-ethylenediaminetetraacetic acid (TE) buffer with trypain for dissolution of calcium oxalate calculi in vitro.Methods Ten patients with calcium oxalate crystals stones were collected clinically.Calcium oxalate calculus was dissolved with the litholytic agents ethylenediaminetetraacetic acid (EDTA),TE buffe or TE buffer with trypain.The calcium of irrigating solution was determined by atomic absorption spectrophotomatry.Dry weighing stones before and after weighing,and the surface of irrigated calculi were observed by scanning electron microscope.The pathological changes of bladder mucosae were observed after the rabbit bladders were irrigated.Results The calcium concentration in TE with trypain group [(667.96 ± 46.24) μg/L] was significantly higher than in EDTA group [(414.95 ±50.04) μg/L],TE group [(439.48 ±57.21) μg/L],and EDTA with trypain group [(503.42 ±57.16) μg/L,P ＜0.05].There was no obvious damage under the light microscope.Conclusion TE buffer solution plus trypain dissolved calcium stones with better effect and little damage.It is expected to be further tested and to be applied in the clinical practice for the stone treatment as a new method. Key words: Calcium oxalate calculi;  Tris-ethylenediaminetetraacetic acid buffer;  Trypain