Sousanieh G, Whittier WL, Rodby RA, Peev V, Korbet SM: Percutaneous Renal Biopsy Using an 18-Gauge Automated Needle Is Not Optimal. American Journal of Nephrology DOI 10.1159/000512902
Percutaneous biopsy (PB), of either native or transplanted kidney, is commonly performed using a variety of needle sizes (14, 16 or 18 G), according to the preferences, training, and experience of the operator (nephrologist or interventional radiologist). The complication rate (primarily bleeding) and adequacy of the kidney tissue specimens for pathologic evaluation are competing variables in the choice of needle size.
Sousanieh and coworkers conducted a single-center (Rush University Medical Center, Chicago, USA), retrospective review of their experience with both native and transplant kidney PB between 2010 and 2020 (native PB, n = 592; transplant PB, n = 1,023). The PBs were carried out using 14-G (n =337, native only), 16-G (n = 255 in native and n = 892 in transplant), and 18-G needles (n = 131, transplant only), using a spring-loaded automated biopsy device. All PBs were performed by a nephrologist or a trainee under the direct supervision of a nephrologist.
The needle size employed was compared to the complication rate (hematoma by ultrasound at 1 h post-PB and transfusion requirement) and adequacy assessed by the number of glomeruli by core and total yield of glomeruli. As noted above, all of the native kidney PBs were performed using 14- or 16-G needles, none used 18-G needles, and all of the transplant kidney PB used a 16- or 18-G needle, none used 14-G needles.
The complication rates were statistically similar, regardless of needle size, but 18-G needles in transplant kidney PB showed a non-significant trend for fewer complications. This could not be further evaluated in native kidney PBs. The study may have been underpowered to show a safety superiority of 18-G needles in transplant kidney PBs. The number of cores obtained was somewhat lower when higher-gauge needles were used in native and transplant kidney PB. The total number of glomeruli (combining light, immunofluorescence, and electron microscopy) were lower with higher-gauge needles (14 vs 16 G in native and 16 vs 18 G in transplant), suggesting that the adequacy of the specimens obtained might be improved by the use of lower-gauge needles. Specimens containing >20 glomeruli were found in 85%, 82/83%, and 46% of the PBs obtained by 14-, 16-, and 18-G needles, respectively. Optimal safety and adequacy were associated with the use of 16-G needles, but the absence of data on 18-G needles in native kidney PB and 14-G needles in transplant kidney limits generalization of this conclusion to all needles and all kidney types. Nevertheless, the lack of association of needle size with complication rates (except for the proviso mentioned above), and the better adequacy of specimen collection with lower-gauge needles, supports their preferential use.