Efficacy and safety of primary needle-knife fistulotomy in biliary cannulation: a systematic review and meta-analysis.

We aimed to conduct a systematic review and meta-analysis on the efficacy and safety of primary needle-knife fistulotomy (NFK) in biliary cannulation. An electronic bibliographic search of digital dissertation databases was performed from inception till March 2020. All prospective studies, including randomized trials evaluating the use of NFK as a primary cannulation technique in biliary cannulation, were analyzed. The primary outcome was a successful cannulation rate and the secondary outcomes were post-ERCP pancreatitis rate and overall post-ERCP complication rate. A total of four prospective studies, including three randomized trials, were included for the analysis. The pooled cannulation success rate for primary NFK was 95.7% (95% CI. 83.1-99.0, P < 0.001). When compared with standard wire-guided cannulation, the analysis did not show any difference between the two techniques in terms of cannulation success (OR, 3.59, 95% CI, 0.34-37.39; P = 0.28; low certainty of evidence). The overall rate of post-ERCP pancreatitis with primary NFK was 1.5 % (95% CI, 0.6-3.9, P < 0.001). When compared with conventional wire-guided technique, the odds of developing post-ERCP pancreatitis with NFK were 0.22 (95% CI, 0.04-1.04, P = 0.06; moderate certainty of evidence). To conclude, NKF seems to be an effective means of biliary cannulation in expert hands. Although it may be associated with a lower rate of post-ERCP pancreatitis, the current strength and quality of evidence to support its use as a primary cannulation strategy is low. It may be considered in ERCPs at higher risk of pancreatitis by experienced endoscopists.