Failure of piezoelectric lithotripsy of a gallstone impacted in the gallbladder neck.

Failure of extracorporeal shockwave lithotripsy is most frequently related to total stone mass, the size of individual stones, or unrecognized stone calcification which interferes with the dissolution effects of orally administered bile salts. We report a case of piezoelectric extracorporeal shockwave lithotripsy failure in a young woman with a 2-cm stone impacted in the neck of the gallbladder. Despite adequate positioning of the shockwave focal point on two separate occasions, no fragmentation was achieved. The stone was subsequently retrieved after the woman underwent laparoscopic cholecystectomy. When treated ex vivo, the stone rapidly fragmented. We hypothesize that the impacted stone, lacking a uniform liquid interface, failed to fragment because of the inability of cavitational forces to achieve a surface effect.