# Non-invasive quantitative assessment of urethral compliance in rabbit tubularized incised plate model using ultrasound and uroflowmetry

## TL;DR

This study uses non-invasive methods like ultrasound and uroflowmetry to assess urethral compliance in rabbits after a specific surgical procedure.

## Contribution

The study introduces a non-invasive method to evaluate urethral compliance in a rabbit model using ultrasound and uroflowmetry.

## Key findings

- Non-invasive methods showed no significant difference in urethral compliance between control and surgery groups.
- Urinary flow rate and urethral diameter can serve as non-invasive indicators of urethral compliance.
- Tubularized incised plate surgery does not significantly affect urethral compliance in rabbits.

## Abstract

Low urinary flow rates are frequently observed following tubularized incised plate urethroplasty. The underlying cause is not yet fully understood and may be associated with low urethral compliance. The purpose of this study is to non-invasively evaluate the urethral compliance in a rabbit model. Ten male New Zealand rabbits were randomly divided into a control group and a urethroplasty group for tubularized incised plate urethroplasty. Seven weeks post-operatively, ex vivo urethral compliance was evaluated using both the Jesus invasive measurement and the non-invasive method. The Jesus measurement involved measuring urethral volume and pressure by air insufflation, and the non-invasive method utilized ultrasound and uroflowmetry to assess the urethral anterior-posterior diameter and flow data, respectively. Curve regression analysis was applied to calculate urethral compliance. Curve regression analysis revealed that the median urethral compliance measured by non-invasive method in the control group was 0.247 (0.241, 0.257) mm•s/ml, and it was 0.269 (0.263, 0.270) mm•s/ml in the urethroplasty group, with no significant difference between the two groups. The Jesus method indicated median urethral compliance was 0.141 (0.137, 0.149) ml/cmH2O for the control group and 0.182 (0.173, 0.192) ml/cmH2O for the urethroplasty group, showing no significant statistical difference. In the rabbit model, urinary flow rate and anterior-posterior diameter serve as non-invasive indicators that can effectively reflect urethral compliance, and TIP surgery has no significant impact on urethral compliance.

The online version contains supplementary material available at 10.1038/s41598-025-11701-8.