Fork-tip and Franseen needles provide higher diagnostic accuracy for autoimmune pancreatitis than reverse/forward-bevel needlesSpecific Needle Types Improve Diagnosis of Autoimmune Pancreatitis

BACKGROUND AND AIM: Autoimmune pancreatitis (AIP) is a rare chronic form of pancreatitis mediated by autoimmune mechanisms. Evidence regarding the diagnostic performance of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) in AIP remains limited. This study aimed to estimate the pooled diagnostic accuracy of EUS-FNB in patients with AIP. METHODS: PubMed, Embase, Cochrane Library, CNKI, and Wanfang Database were systematically searched to identify fully published studies evaluating EUS-FNB for tissue sampling in AIP. Pooled estimates were generated using a random-effects model. The assessed outcomes included diagnostic accuracy, sample adequacy, contribution to AIP diagnosis, and adverse events. RESULTS: Sixteen studies, including one randomized controlled trial and four prospective studies, comprising 732 patients, were included. The overall diagnostic accuracy was 79% (73%-83%). Diagnostic accuracy was higher for the Franseen needle (83%, 75%-90%) and Fork-tip needle (90%, 80%-99%) compared with the reverse/forward‑bevel (51%, 31%-71%), with a statistically significant difference (P < 0.001). The 22G needle also demonstrated superior diagnostic accuracy (85%, 79%-91%) compared with 19G/20G needles (70%, 42%-98%) (P < 0.001). The pooled sample adequacy rate was 97% (95%-98%). EUS-FNB contributed to the diagnosis in 69% (50%-88%) of cases where diagnosis could not be established using imaging, serology, or involvement of other organs. The overall adverse event rate was 4% (1%-8%). CONCLUSIONS: EUS-FNB demonstrates excellent histological tissue acquisition and moderate diagnostic accuracy in AIP, with a low rate of adverse events. The 22G Franseen or Fork-tip needles may be a reasonable option, though direct comparative evidence is lacking.