Systematic Measurement of Membranous Urethral Length Using a Cross-Reference System: A Study on Interrater
Jongkyou Kwon1, Sungun Bang1, Jinhyung Jeon2
1Department of Urology, Prostate Cancer Center, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
The World Journal of Men'S Health
|October 5, 2025
Summary
A new cross-reference system (CRS) significantly improved the consistency of membranous urethral length (MUL) measurements between different doctors. This standardization enhances anatomical accuracy and continence prediction after robot-assisted radical prostatectomy (RARP).
Area of Science:
- Urology
- Radiology
- Surgical Outcomes
Background:
- Accurate measurement of membranous urethral length (MUL) is crucial for predicting post-prostatectomy continence.
- Interrater variability in MUL measurements can impact the reliability of these predictions.
- Standardization of measurement techniques is needed to improve reproducibility.
Purpose of the Study:
- To evaluate the effectiveness of a cross-reference system (CRS) in enhancing the reproducibility of membranous urethral length (MUL) measurements.
- To assess the impact of CRS on reducing interrater variability in MUL measurements.
- To determine if CRS improves the predictive value of MUL for post-RARP continence.
Main Methods:
- 100 patients undergoing robot-assisted radical prostatectomy (RARP) with preoperative MRI were included.
- Membranous urethral length (MUL) was measured by two urologists before and after implementing a cross-reference system (CRS).
- Interrater variability and agreement with radiological reference measurements were analyzed using Bland-Altman methods.
Main Results:
- The cross-reference system (CRS) significantly reduced interrater variability and improved agreement in membranous urethral length (MUL) measurements.
- While MUL was not a significant predictor of continence at 6 months, it remained significant at 12 months post-RARP.
- CRS modestly improved the predictive discrimination and calibration of MUL for continence at 12 months.
Conclusions:
- A systematic, cross-reference system (CRS)-based approach enhances the reproducibility of membranous urethral length (MUL) measurements.
- Standardized MUL measurements are essential for improving anatomical accuracy and predicting urinary continence after robot-assisted radical prostatectomy (RARP).
- Further validation of CRS for MUL measurement in larger cohorts is warranted.
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