Gallstone dissolution--a progress report.

Cholesterol gallstone formation occurs in three stages. First, the bile must be saturated with cholesterol, thereby allowing cholesterol crystals to form. Then, nucleation and growth of the gallstone can occur, although little is known about these latter two stages. Therapy for dissolution of gallstones is directed at desaturating the bile. Chenodeoxycholic acid (CDCA), the most extensively tested agent, is successful in dissolving 60 per cent of radiolucent gallstones; however, long-term safety remains to be demonstrated. Ursodeoxycholic acid (UDCA), the 7 beta epimer of CDCA, is a promising agent for cholesterol gallstone dissolution, but it, other potential agents, and dietary manipulations require more extensive study. An important problem, the prevention of recurrence of gallstones after dissolution, also needs resolution. Medical dissolution probably will be applicable as an alternative to cholecystectomy for most patients with radiolucent gallstones, but the specific relative indications remain to be determined. A variety of modalities, both medical and surgical, are being used for the treatment of retained or reformed bile duct stones. These include T-tube infusions, oral CDCA, and extraction either through the T-tube tract or after endoscopic papillotomy. Further studies, including controlled trials, are necessary to determine the relative indications for these methods.