# Straightforward and immediate ultrasound-guided kidney biopsy using a guide needle technique to get adequate tissue with reduced procedural time

## TL;DR

A new kidney biopsy technique called SIGN reduces procedure time and improves tissue collection, especially for less experienced doctors.

## Contribution

The SIGN technique introduces a guide needle method for faster and more effective ultrasound-guided kidney biopsies.

## Key findings

- The SIGN group had a significantly shorter median procedure time (2 min) compared to the conventional method (3 min).
- The SIGN technique was independently associated with obtaining a higher number of glomeruli.
- Complication rates were similar between the SIGN and conventional groups.

## Abstract

A streamlined and effective renal biopsy technique is essential for all nephrologists, particularly those who are less experienced, such as residents. Herein, we report the efficacy of a Straightforward and Immediate ultrasound-guided kidney biopsy using a Guide Needle (SIGN) technique, which allows operators to insert a biopsy gun through a guide needle placed into the fascia of the posterior abdominal wall.

A retrospective cross-sectional study was conducted at a nephrology training institution to compare the time spent on the procedure and the number of glomeruli obtained between a group using the SIGN (n = 81) and a group using the conventional ultrasound-guided kidney biopsy technique with a needle guide device (n = 143).

The median procedure time in the SIGN group (2 min, interquartile range [IQR]: 1–3 min) was significantly shorter than that in the conventional group (3 min, IQR: 2–4 min) (P < 0.001). Multivariable linear regression and logistic regression analyses adjusted for covariates, including operators (board-certificated nephrologists or nephrology residents), showed that the use of the SIGN technique was independently associated with a high number of glomeruli obtained and a procedure time above 2 min as the median value (odds ratio: 0.17, 95% confidence interval CI 0.09–0.34). The prevalence of complications was comparable between the two groups (P = 0.681).

The SIGN technique reduces the procedure time and obtains adequate biopsy tissue regardless of the operator’s experience. SIGN can be applied in nephrology training programs and used as a standard biopsy technique.

The online version contains supplementary material available at 10.1007/s10157-024-02544-0.