Prediction of successful treatment by extracorporeal shock wave lithotripsy based on crystalluria-composition correlations of urinary calculi

Abstract

Objective: To provide correlations between crystalluria and chemical structure of calculi in situ to help making decision in the use of the extracorporeal shock wave lithotripsy ( ESWL ). Methods: A crystalluria study was carried out on 644 morning urines of 172 nephrolithiasis patients (111 males and 61 females), and 235 of them were in situ stone carriers. After treating by ESWL , the recovered calculi have been analyzed by Fourier transform infrared spectroscopy and their compositions were correlated to the nature of urinary crystals. Results: We obtained successful treatment for 109 patients out of 157 and 63 patients out of 78 with stones had a treatment failure (33.2%). The correlations showed that for the overwhelming crystalluria containing calcium oxalate dihydrate ( COD ) with mixed crystals without calcium oxalate monohydrate, we should have 68% to 88 % success rate. However, the obtained result was 79%. Similarly, for crystalluria with COD + calcium oxalate monohydrate ± carbapatite, the prediction was 11% to 45% and the result was approximately 39%. When the majority of crystalluria was calcium phosphate, the prediction of 50% to 80% was confirmed by 71% success rate. For those majority containing magnesium ammonium phosphate hexahydrate (struvite) ± diammonium urate ± COD , we predicted between 80% to 100%, and the result gave a success rate of 84%. Conclusions: The analysis of crystalluria of morning urine can help to know the composition of calculi in situ and can predict the success rate of ESWL for maximum efficiency.