Optimization of Pediatric Kidney Biopsy: Impact of Needle Size and Passes

This study evaluated the impact of needle size and the number of passes on complication rates and glomerular yield in pediatric native kidney biopsies performed under real-time ultrasound (US) guidance, aiming to determine the optimal biopsy approach.

Pediatric native kidney biopsies performed between March 2019 and February 2022 at a single tertiary-care children's hospital were included. Biopsies were done with a semi-automated 16 G needle until December 2020, then with an 18 G needle, with varying numbers of passes. US examinations were conducted 24 h post-biopsy to assess complications. Patients were categorized into six subgroups using needle size and the number of passes and compared for complication rates, glomerular yield, and diagnostic adequacy.

A total of 145 pediatric patients (59.3% female, 40.7% male) with a mean age of 10.74 (±4.69) years were included. An 18 G needle was used in 76 (52.4%) cases and a 16 G needle in 69 (47.6%) cases. Minor complications occurred in 56 (38.6%) cases, with no major complications. Complication rates were not significantly different between 18 G and 16 G (p=0.088) but increased with the number of passes (p<0.001). Mean glomerular yield was higher with 16 G than 18 G (34.6 vs. 22.6, p<0.001), though not significantly affected by the number passes (p=0.123). The 18 G needle was associated with inadequate sampling (p=0.024). The optimal scenario was a 16 G needle with one or two passes.

Real-time US-guided pediatric kidney biopsy is safe. A 16 G needle with one or two passes optimizes glomerular yield without increasing complications. Three or more passes should be avoided.