Long-term follow-up after peroral cholangioscopy-directed lithotripsy in patients with difficult bile duct stones, including Mirizzi syndrome: an analysis of risk factors predicting stone recurrence.

BACKGROUND: Peroral cholangioscopy-directed lithotripsy (PC-directed lithotripsy) has been successfully used for the treatment of difficult bile duct stones, including Mirizzi syndrome (MS). However, long-term outcome and risk factors for stone recurrence after PC-directed lithotripsy have not yet been elucidated. The aim of this study was to assess the outcomes of long-term follow-up after PC-directed lithotripsy and to clarify risk factors predicting stone recurrence.

METHODS: One hundred twenty-two consecutive patients with difficult bile duct stones, including MS type II (McSherry classification system), were included in the study.

RESULTS: Successful stone removal was achieved in 117 (95.9%) of the 122 patients treated with PC-directed lithotripsy. Of these 117 patients, reliable follow-up information for a median period of 5.5 years (range=0.19-16.6) was obtained for 111 patients (94.9%) in whom stone type was classified into one of the following three categories: (1) MS type II (47 patients); (2) impacted stones (45 patients); and (3) large stones (≥20 mm in short diameter, 19 patients). Bile duct stone recurrence was observed in 18 patients (16.1%), of whom 4 had MS type II, 9 had impacted stones, and 5 had large stones. Statistical analysis showed that dilated bile duct diameter greater than or equal to 20 mm was the only risk factor for stone recurrence.

CONCLUSIONS: PC-directed lithotripsy used for the treatment of difficult bile duct stones, including MS type II and impacted stones, and is found to be safe at long-term follow-up. Dilated bile duct diameter is the only risk factor for stone recurrence. Careful follow-up is indispensable, particularly for patients with dilated bile ducts.