Outcomes of Endoscopic Ultrasound-guided Fine Needle Biopsy Using a Novel Hydrostatic Stylet Tissue Acquisition Technique

Background:Endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) is frequently used to obtain core samples of solid lesions. Here, we describe and evaluate a novel hydrostatic stylet (HS) technique designed to optimize core sample acquisition, reporting diagnostic yield, efficacy, and safety relative to the conventional stylet slow-pull (SP) technique. Methods: A novel HS technique was developed and validated retrospectively. Consecutive patients who underwent EUS-FNB with core biopsy of solid lesions through either the HS or SP technique between January 2020 and April 2022 were included. Exclusion criteria included cystic lesions, nonlesional liver biopsies, and specimens sent for cytologic analysis only. Patient and lesion characteristics, number of passes, sample adequacy, and adverse events were compared between the two techniques. Results: A total of 272 patients were included with 138 in the HS group and 134 in the SP group. Lesion size and anatomic distribution were similar in both groups. Compared with the SP approach, the HS technique demonstrated significantly higher sample adequacy (97.8% vs 83.6%, P < 0.001), higher sensitivity (97.1% vs 89.7%, P = 0.03), and lower mean number of passes (1.2 vs 3.3, P < 0.001). Rates and severity of adverse events in the HS group were comparable to the SP group and existing literature. Similar associations were observed in pancreatic and nonpancreatic lesion subanalyses. Conclusions: The novel HS technique demonstrated excellent biopsy sample adequacy and diagnostic yield while requiring fewer passes to obtain diagnostic specimens compared with a conventional EUS-FNB approach. Further prospective evaluation is needed to confirm these pilot findings and optimize EUS-FNB acquisition techniques.