Ten years experience with piezoelectric extracorporeal shockwave lithotripsy of gallbladder stones

Background A critical review of the experience with extracorporeal shockwave lithotripsy (ESWL) of gallbladder stones is needed to clarify whether this method should continue to be applied to patients. Methods Patients with symptomatic gallbladder stones were treated by piezoelectric ESWL according to a prospective protocol between 1988 and 1997 ESWL treatment was limited to a maximum of three (solitary stones < 20mm diameter) to five sessions (larger solitary or multiple stones) and 3000 pulses per session. Univariate and multivariate analyses of pretreatment and treatment variables were performed to investigate their impact on fragmentation efficacy and stone clearance. A tree-based analysis was used to identify prognostically homogenous subgroups of individuals with maximum benefit from ESWL. Results Four hundred and eight patients, 76% female and 24% male, with a mean age of 46 (SD, 13) years, were selected for evaluation. Cox regression analysis identified three pretreatment variables with significant prognostic impact: (1) number of gallstones > 1 (relative risk, 2.6 (95% Cl, 1.9-3.5)), (2) size of stones > 17 mm (1.7 (1.4-2.2)), and (3) computed tomography (CT) density of stones > 55 Hounsfield units (H) (0.4 (1.1-1.8)). According to tree-based analysis, the stone clearance rate after 1 year was 85% (95% Cl, 75-91%) for solitary stones < 16 mm, 79% (70-86%) for solitary stones >= 16 mm with a CT density < 84 H, 45% (32-55%) for solitary stones >= 16 mm with a CT density >= 84 H, and 42% (30-51 %) for multiple stones. Five years after stone clearance, recurrence occurred in 43% of patients (95% Cl, 39-47%). Conclusions ESWL treatment showed an acceptable stone clearance in the case of small solitary gallbladder stones (< 16 mm) or larger solitary stones with a CT density < 84 H, but a very low success rate in the case of multiple stones. The poor long-term success, however, is an important argument against the use of ESWL of gallbladder stones. (c) 2005 Lippincott Williams & Wilkins.