Is the Isolated-Tip Needle-Knife Precut as Effective as Conventional Precut Fistulotomy in Difficult Biliary Cannulation?

BACKGROUND/AIMS: Needle-knife precut fistulotomy (NK-F) is a well-known freehand technique for difficult biliary cannulation (DBC). Another approach involves the use of Iso-Tome(®), a modified precutting device with an insulated needle tip to prevent direct thermal injury. This comparative study aimed to evaluate the efficacy of the Iso-Tome(®) precut (IT-P) compared to that of NK-F for DBC. METHODS: Patients with a naive papilla who underwent early IT-P or NK-F for DBC were enrolled. DBC was defined as failure to achieve selective biliary access by wire-guided cannulation despite 5 minutes of attempted cannulation, ≥5 papillary contacts, or a hook-nose-shaped papilla. The primary endpoint was the primary technical success rate, which was based on a noninferiority model. RESULTS: A total of 239 DBC cases were enrolled. The primary technical success rates were 74.7% (89/119) in the IT-P group and 91.6% (110/120) in the NK-F group (lower limit of 90% confidence interval, −0.23; p=0.927 for a noninferiority margin of 10%). The total technical success rates were 87.4% and 95.0%, respectively (p=0.038). The mean precutting times for successful biliary access were 11.2 minutes for IT-P and 7.3 minutes for NK-F (p<0.01). The procedure-related adverse event rates were 9.2% for IT-P and 5.8% for NK-F (p=0.318). The rates of post-endoscopic retrograde cholangiopancreatography pancreatitis were 4.2% and 2.5%, respectively (p=0.499). CONCLUSIONS: IT-P failed to exhibit noninferiority compared with NK-F regarding the primary technical success rate of DBC, but there was no difference in the frequency of adverse events.