Biliary lithotripsy: correlation between gallbladder contractility before treatment and the success of treatment

We perform biliary lithotripsy without adjuvant chemolitholytic agents, and therefore fragment clearance depends solely on the gallbladder's ability to evacuate its contents. We studied 205 patients to determine if gallbladder contractility before biliary lithotripsy is a predictor of treatment results and rate of fragment clearance. Percentage gallbladder contraction was calculated from the fractional difference in the sonographically measured gallbladder volumes before and after a fatty meal. Seventy-six patients (37%) were free of stones and fragments, and 129 patients (63%) had residual fragments at comparable follow-up intervals. Statistical analysis showed a significant difference in gallbladder contractility before biliary lithotripsy between the fragment-free group and the residual-fragment group (p = .008). Stone burden before treatment showed no significant difference between the groups (p = .074), but the number of stones was significantly less in the fragment-free group (p = .022). In the fragment-free group, a poor correlation (r = .047) was found between the percentage gallbladder contraction and the rate of fragment clearance. These data indicate that contractility of the gallbladder before treatment correlates with overall success of biliary lithotripsy but is not a predictor of the speed of fragment clearance.