B0449 - Outcomes of Endoscopic Ultrasound-Guided Fine Needle Biopsy Using a Novel Hydrostatic Stylet Technique

Introduction: Endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) is frequently used to obtain core samples for the diagnostic evaluation of solid lesions. The optimal technique for tissue acquisition using core biopsy needles remains uncertain. Here we report the outcomes of a novel hydrostatic stylet (HS) technique for core biopsy acquisition and evaluate its diagnostic yield, efficacy, and safety compared to conventional stylet slow-pull (SP).

Methods: The steps of the HS technique are detailed in Figure 1. We performed a retrospective analysis of patients who underwent EUS-FNB with core biopsy of solid lesions via HS or SP between January 2020 and April 2022. Exclusion criteria included cystic lesions, non-lesional liver biopsies, and specimens sent for cytological analysis only. Patient and lesion characteristics, the number of passes, sample adequacy, and adverse events were compared between HS and SP techniques.

Results: A total of 272 patients were included with 138 in the HS group and 134 in the SP group (Table 1). The anatomic distribution and size of lesions were similar in both groups with the head of the pancreas and lymph nodes being the two most common locations. The most utilized needle size was 22-gauge in both techniques. Compared to the SP approach, the HS technique demonstrated a significantly lower mean number of passes (1.2 vs 3.5, P< 0.001), higher sample adequacy (97.8% vs 83.6%, P< 0.001), and higher sensitivity (97.1% vs 89.7%). Rates and severity of adverse events in the HS group were comparable to the SP group (1.5% vs 2.2%, P=0.63) and existing literature.

Discussion: The novel HS technique demonstrated significantly improved biopsy sample adequacy and diagnostic yield while requiring fewer passes to obtain higher diagnostic success compared to a conventional EUS-FNB approach. Further prospective evaluation is needed to confirm these pilot findings and optimize EUS-FNB technique.