PANCREATOSCOPY-GUIDED ELECTROHYDRAULIC LITHOTRIPSY FOR THE TREATMENT OF OBSTRUCTIVE DISTAL MAIN PANCREATIC DUCT STONES: A PROSPECTIVE CONSECUTIVE CASE SERIES (PELSTONE STUDY)

Aims Pancreatoscopy-guided electrohydraulic lithotripsy (EHL) has shown potential in the treatment of patients with obstructive chronic calcifying pancreatitis (CCP), but is used as second-line therapy after extracorporeal shockwave lithotripsy (ESWL). We aimed to investigate the efficacy and safety of EHL as first-line therapy in patients with CCP of the distal pancreatic duct (PD).

Methods A prospective single center consecutive case series was performed in CCP patients presenting with obstructing stones of >5mm in the head or neck of the pancreas. Stone fragmentation was performed using EHL. The primary study outcome was technical success (i.e. ability to visualize the intraductal stones and achieve fragmentation, complete (100%) or partial (≥50%), with resolution of PD outflow obstruction. Secondary outcomes were clinical success (Izbicki pain score), adverse events and number of interventions.

Results Thirty-three consecutive patients were considered. Pancreatoscopy was not performed due to failure to cannulate the PD (n=5) or resolution of stones after stent placement at the initial ERP procedure (n=3). When pancreatoscopy was attempted, technical success was achieved in 24 out of 25 patients (96%), with complete and partial stone clearance in 19 patients (79.2%) and 5 patients (20.8%), respectively. In one patient the stone could not be visualized with pancreatoscopy due to distal strictures. PD clearance was achieved after a median of 2 (IQR2) ERP procedures and 1 (IQR 1) EHL procedure. In 13 patients (54.2%) a stent was placed first to facilitate pancreatoscopy at second ERP. Mean Izbicki pain score at baseline was 62.4 ± 21.6 (n=24/24), and dropped significantly to 22.3 ± 30.3 (15/18) at six months follow-up (p=0.006). Adverse events included pancreatitis (n=8) and cholangitis (n=1), all mild and treated conservatively.

Conclusions Pancreatoscopy-guided EHL is a highly effective treatment for symptomatic CCP patients with a dilated PD due to distal obstructive PD stones. Adverse events, occur relatively frequent, but are mild.