Holmium:YAG lithotripsy: photothermal mechanism converts uric acid calculi to cyanide.

Teichman, J M; Vassar, G J; Glickman, R D; Beserra, C M; Cina, S J; Thompson, I M · J Urol · 1998

basic_science · Level V

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Abstract

Holmium:YAG lithotripsy fragments stones through a photothermal mechanism. Uric acid when heated is known to be converted into cyanide. We test the hypothesis that holmium: YAG lithotripsy of uric acid calculi produces cyanide. Human calculi of known uric acid composition were irradiated with holmium:YAG energy in water. Stones received a total holmium:YAG energy of 0 (control), 0.1, 0.25, 0.5, 0.75, 1.0 or 1.25 kJ. The water in which lithotripsy was performed was analyzed for cyanide concentration. A graph was constructed to relate holmium:YAG energy to cyanide production. Holmium:YAG lithotripsy of uric acid calculi in vitro produced cyanide consistently. Cyanide production correlated with total holmium:YAG energy (p <0.001). Holmium:YAG lithotripsy of uric acid calculi risks production of cyanide. This study raises significant safety issues.

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