Needle-knife sphincterotomy does not independently increase post-ERCP pancreatitis: a 20-year retrospective cohort study with propensity score matching.

BACKGROUND

Precut techniques and needle-knife sphincterotomy (NKS) are commonly employed to achieve biliary access in cases of difficult cannulation during ERCP. Although historically associated with increased complications, recent data suggest this risk may reflect procedural complexity rather than the technique itself. This study aimed to evaluate the independent association of NKS with post-ERCP pancreatitis (PEP) and other adverse events using a large, single-operator cohort.

METHODS

We conducted a retrospective observational study, analyzing data from a prospectively maintained database of 2786 therapeutic ERCPs performed by a single experienced endoscopist between 2001 and 2021. Patients were categorized into those undergoing NKS after failed standard cannulation and those receiving primary endoscopic sphincterotomy (ES). Propensity score matching (PSM) and multivariable logistic regression were used to adjust for baseline and procedural confounders. A predefined subgroup of difficult standard ES cases (≥ 5 cannulation attempts) was also compared with NKS.

RESULTS

PEP occurred more frequently in the NKS group than in the ES group (3.7% vs. 1.4%, p < 0.001), but this association lost statistical significance after adjustment (adjusted OR: 1.68, 95% CI: 0.91-3.26, p = 0.11). Independent predictors of PEP included ≥ 5 cannulation attempts, pancreatic duct cannulation, and acinarization. In subgroup analysis, PEP rates did not differ significantly between NKS and difficult ES cases. Perforation remained significantly more frequent in the NKS group (adjusted OR: 5.35, 95% CI: 1.82-21.3), while bleeding rates were similar. Overall complications were higher with NKS (adjusted OR: 1.80, 95% CI: 1.20-2.72), largely due to perforation.

CONCLUSIONS

NKS does not independently increase the risk of PEP when procedural complexity is accounted for, but carries a higher risk of perforation. Early transition to NKS in appropriately selected cases may reduce unnecessary trauma and improve outcomes. Operator expertise remains critical to optimizing safety.