Impact of endoscopic papillary large-balloon dilation on sphincter of Oddi function: a prospective randomized study

Background and Aims: Endoscopic papillary balloon dilation (<= 8 mm in diameter) preserves sphincter of Oddi (SO) function. However, it is still unknown whether papillary function is preserved after endoscopic papillary large-balloon dilation (EPLBD, >= 12 mm in diameter). We investigated SO function after EPLBD with or without endoscopic sphincterotomy (EST) by endoscopic manometry, up to 1 year after the procedure. Methods: This was a prospective randomized study involving patients with bile duct stones >= 12 mm. Eighty-six patients who met the inclusion criteria were assigned randomly to either EPLBD alone or EST with EPLBD, and endoscopic manometric studies were performed. The primary outcome was comparison of the manometric data between the 2 groups and within each group both 1 week and 1 year after the procedure. Results: One week after EPLBD alone and EST with EPLBD, the basal pressure of SO dropped from 30.4 (8.2) to 6.4 (8.4) mm Hg (P < .001) and 29.5 (18.9) to 2.9 (3.6) mm Hg (P < .001), respectively. SO function was not recovered at 1 year; the manometric measurements were similar to those taken at the 1-week time point in both groups. Similar outcomes were obtained in patients with EPLBD alone compared with those with EST and EPLBD, including the initial stone clearance rate (95.2% vs 97.7%, P = .612), the frequency of mechanical lithotripsy (21.4% vs 13.6%), and overall adverse events (11.9% vs 13.6%, P = 1.0) including the rate of pancreatitis after the procedure (7.1% vs 11.4%, P = .714). During an overall median follow-up of 17.8 months, the recurrence rate of bile duct stones was 16.7% in patients who underwent EPLBD alone and 15.9% in patients who underwent EST with EPLBD (P = .924). Conclusions: Both EPLBD alone and EST + EPLBD resulted in persistent and comparable loss of SO function after 1 year. EPLBD alone has similar efficacy and safety to those of EST with EPLBD with respect to removal of large stones.