GEOGRAPHIC VARIATIONS IN STRUCTURE AND COMPOSITION OF GALLSTONES AND THEIR CORRELATION WITH BRITTLENESS

Cholesterol gallstones obtained from different geographic regions have been reported to show significant differences in their minor chemical constituents. We undertook the present study with two objectives: (i) to investigate the possible physicochemical and radiological differen ces between cholesterol gallstones obtained from Indian and German pat ients; and (ii) to compare the brittleness of the two stone groups. Fo rty Indian and 36 German gallstones (matched in size and shape) were s ubjected to assessment of physical characteristics, in vitro computed tomography (CT) and chemical analysis. German stones more often had a stone density distribution index of greater than or equal to 50 Hounsf ield units (HU) (26 vs 14; P < 0.01), peripheral calcification (18 vs 9; P < 0.02), maximum CT density greater than or equal to 90 HU (17 vs 9; P < 0.05) and significant calcium carbonate (9 vs 5; P < 0.05), co mpared to Indian stones. The in vitro lithotripsy performed with the S iemens Lithostar Plus machine at a constant energy level showed the Ge rman stones to be more brittle (easy to fragment), more often requirin g < 1000 shocks for fragmentation (25/36; 69%) compared to Indian ston es (18/40; 45%, P < 0.05). Gallstones from different geographic region s may show significant variations in their physicochemical characteris tics that may explain the differences in their brittleness to lithotri psy.