Crystalline Composition of Urinary Stones.

Introduction. By means of an X-ray diffractometer, it is possible to very precisely determine the composition of examined stones while identifying each kind of crystal. The objective of this paper is to make an in vitro assessment of the crystalline composition of urinary stones obtained during surgeries or those spontaneously excreted by the patients treated in the I and II Clinic of Urology of the Medical University in Lódź. Material and method. The research was conducted with the use of X-ray diffractometers: Dron - 1 or D 5000 Siemens. One hundred eighty-eight urinary stones obtained from patients treated in the clinics were examined. Results. The following crystals were found in the examined urinary stones: whewellite occurs in 97 (51.6%) stones, weddellite in 45 (23.9%), struvite in 82 (43.6%), apatite in 70 (37.2%), newberyite in 40 (21.2%), brushite in 34 (18.1%), bobierrite in 14 (7.4%), vitlokite in 7 (3.7%), uric acid in 12 (6.4%), ammonium acid urate in 1 (0.5%), calcium carbonate in 3 (1.6%), cystine and other sporadically occurring crystals were found in 0.6% to 1% of cases. Stones made of pure calcium oxalate constituted 18.1%. Oxalic stones with the additive of other crystals, although not containing any struvite, were found in 20.2% of cases, which in total makes 38% of the analyzed stones. Pure struvite stones constituted 5.3% and the ones with the additive of other phosphate crystals - 27.7%, which makes 33.0% in total. Uric acid stones constituted 5.3%, whereas with the additive of other crystals - 1.1%, which makes 6.4% in total. Cystine stones were found in 0.6% of cases. Mixed stones containing all kinds of crystals constituted 22.0%. Conclusions. Diffractometric studies allow very precise determination of the composition of urinary stones. While using the crystalline structure as a criterion for dividing urinary stones, one cannot create any homogenous groups. On the basis of the conducted research, we divided urinary stones into oxalic, phosphate, uric acid, cystine, and mixed ones, the latter containing all possible kinds of crystals. The largest group is made of mixed stones, which constitute 55% of the deposits and combine infected stones without calcium oxalate and stones that are a mixture of struvite and calcium oxalate as well as other crystals. Another numerous group is made of oxalic stones - 38.3% of cases. Uric acid stones (6.4%) and cystine stones (0.6%) are less frequent. Based on the observations conducted it can be concluded that along with the increase in the number of crystals contained in a uric stone, the number of uric acid deposits decreases and the number of stones made of phosphate and mixed oxalic and phosphate crystals, often with the additive of struvite, grows. [ABSTRACT FROM AUTHOR]