Safety and Efficacy Performance of Coaxial 18G vs. 20G Needles for Pediatric Percutaneous Liver Biopsy: A Retrospective Cohort Study

Background: Percutaneous liver biopsy is a cornerstone in the diagnostic and therapeutic management of pediatric liver diseases. However, data on the optimal needle gauge for coaxial techniques in children remain scarce. Smaller-gauge needles may theoretically enhance safety but could potentially compromise diagnostic yield. Objectives: The primary objective of this study was to evaluate and compare the safety and diagnostic clinical adequacy of ultrasound-guided percutaneous liver biopsies performed with semi-automated 20G versus 18G coaxial needles in pediatric patients. Patients and Methods: This retrospective cohort study included consecutive patients aged ≤19 years who underwent percutaneous non-targeted liver biopsies at a tertiary medical center between 2006 and 2012. Patient demographics, biopsy technique parameters (including needle gauge, number of cores, and tract embolization), and procedure-related complications were analyzed. Procedural success was defined by diagnostic and clinical adequacy, requiring a definitive pathology report and the presence of ≥7 portal tracts (the widely accepted threshold for a reliable histologic diagnosis). Complications were classified according to the Society of Interventional Radiology guidelines. Results: A total of 320 biopsies were performed in 260 patients (44.6% female; mean age 7.4 ± 6.0 years). Common indications included post-liver transplantation surveillance (28.4%) and unexplained liver enzyme elevation (22.5%). Biopsies were performed using 18G (n = 148; 46.3%) or 20G (n = 172; 53.7%) coaxial needles. Diagnostic and clinical adequacy was achieved in 100% of the procedures, with biopsy results directly influencing clinical management in 39.7% of cases. The overall complication rate was 5.3% (3.4% minor, 1.9% major), with no procedure-related mortality. While raw complication rates were numerically higher in the 20G group (likely to reflect an operator-driven selection bias for younger or higher-risk patients), the differences between the 18G and 20G needles were not statistically significant. Notably, the use of the 20G needle was associated with a significantly reduced clinical need for post-biopsy tract embolization. Conclusions: Our findings demonstrate no statistically significant differences in complication rates or diagnostic clinical adequacy between 18G and 20G coaxial needles for pediatric percutaneous liver biopsies. When selected based on appropriate clinical judgment, the 20G needle provides a high diagnostic yield and serves as an effective option, particularly for reducing the need for tract embolization. However, both 18G and 20G needles represent acceptable clinical options within the pediatric interventional armamentarium. Ultimately, the choice of needle gauge should be meticulously tailored to individual patient characteristics, bleeding risk profiles, and specific clinical indications, rather than uniformly recommending a smaller gauge across all pediatric age groups.