Post-voided residual urine ratio as a predictor of bladder outlet obstruction in men with lower urinary tract symptoms: development of a clinical nomogram

Is the time right for a new initiative in mathematical modeling of the lower urinary tract? ICI-RS 2023

INTRODUCTION

A session at the 2023 International Consultation on Incontinence - Research Society (ICI-RS) held in Bristol, UK, focused on the question: Is the time right for a new initiative in mathematical modeling of the lower urinary tract (LUT)? The LUT is a complex system, comprising various synergetic components (i.e., bladder, urethra, neural control), each with its own dynamic functioning and high interindividual variability. This has led to a variety of different types of models for different purposes, each with advantages and disadvantages.

METHODS

When addressing the LUT, the modeling approach should be selected and sized according to the specific purpose, the targeted level of detail, and the available computational resources. Four areas were selected as examples to discuss: utility of nomograms in clinical use, value of fluid mechanical modeling, applications of models to simplify urodynamics, and utility of statistical models.

RESULTS

A brief literature review is provided along with discussion of the merits of different types of models for different applications. Remaining research questions are provided.

CONCLUSIONS

Inadequacies in current (outdated) models of the LUT as well as recent advances in computing power (e.g., quantum computing) and methods (e.g., artificial intelligence/machine learning), would dictate that the answer is an emphatic "Yes, the time is right for a new initiative in mathematical modeling of the LUT."

(A)voiding misdiagnosis: prediction of detrusor underactivity vs. bladder outlet obstruction using pre-urodynamic nomogram in male patients with LUTS

PURPOSE

Our study aimed to develop a noninvasive model using a combination of the set of clinical data and uroflowmetry (UFL) to differentiate between detrusor underactivity (DU) and bladder outlet obstruction (BOO) in non-neurogenic male patients with lower urinary tract symptoms (LUTS).

METHODS

Data from 229 men with LUTS, diagnosed with DU or BOO on a pressure-flow study (PFS), were retrospectively analyzed, including medical history, Core Lower Urinary Tract Symptoms score (CLSS) questionnaire, UFL and PFS. Uni- and multivariate logistic regression were utilized for the prediction analyses.

RESULTS

Of the cohort, 128 (55.9%) patients were diagnosed with DU. A multivariate logistic regression analysis identified less prevalent nocturia (OR 0.27, p < 0.002), more prevalent intermittency (OR 2.33, p = 0.03), less prevalent weak stream (OR 0.14, p = 0.0004), lower straining points in CLSS (OR 0.67, p = 0.02), higher slow stream points in CLSS (OR 1.81, p = 0.002), higher incomplete emptying points in CLSS (OR 1.31, p < 0.02), lower PVR ratio (OR 0.20, p = 0.03), and present features of fluctuating (OR 2.00, p = 0.05), fluctuating-intermittent (OR 3.09, p < 0.006), and intermittent (OR 8.11, p = 0.076) UFL curve shapes as independent predictors of DU. The above prediction model demonstrated satisfactory accuracy (c-index of 0.783).

CONCLUSION

Our 10-factor model provides a noninvasive approach to differentiate DU from BOO in male patients with non-neurogenic LUTS, offering a valuable alternative to invasive PFS.

Post-Voided Residual Ratio Does Not Predict Trifecta Outcome after Transurethral Resection of Prostate

The purpose of this study was to assess the importance of the post-void residual (PVR) ratio (PVR ratio) in achieving a favorable trifecta outcome for patients suffering from lower urinary tract symptoms and benign prostatic enlargement (LUTS-BPE) who undergo transurethral resection of the prostate (TURP). Starting from 2015, a series of patients with LUTS-BPE who underwent TURP were included in a forward-looking study. These patients were assessed using the international prostate symptom score (IPSS) screening tool, uroflowmetry, and a transrectal ultrasound to measure prostate volume (TRUS). Both the PVR urine volume and the PVR ratio (PVR-R), which is the PVR as a percentage of total bladder volume (voided volume + PVR), were measured. The assessment of outcomes was based on the trifecta favorable outcome, defined as meeting all of the following criteria: (1) absence of perioperative complications, (2) a postoperative IPSS of less than eight, and (3) a postoperative maximum urinary flow rate (Qmax) greater than 15 mL/s. A total of 143 patients were included, with a median age of 70 years (interquartile range 65-73). Of these, 58% (83/143) achieved a positive trifecta outcome. Upon conducting a multivariate analysis, both IPSS and Qmax were identified as predictors of a positive trifecta outcome, whereas the PVR-R did not prove to be an independent predictor. In summary, it was found that preoperative IPSS and Qmax are indicative of a trifecta outcome following TURP, whereas PVR-R is not.

A grading system for evaluation of bladder trabeculation

PURPOSE

To establish a parameter-based grading system for evaluating bladder trabeculation (BT).

MATERIALS AND METHODS

A retrospective analysis was conducted on children diagnosed with posterior urethral valve (PUV) or neurogenic bladder (NB) who underwent voiding cystourethrogram (VCUG), urodynamic testing, and urological ultrasonography between January 2016 and October 2022. Cases involving urologic surgery, secondary bladder pathology, and an interval of more than 12 months between examinations were excluded. A parameter named Bladder Dispersion (BD) was calculated through fluoroscopic images, and the grading system was developed as follows: BD < 40 (Grade 0), 40 ≤ BD < 60 (Grade 1), 60 ≤ BD < 90 (Grade 2), BD ≥ 90 (Grade 3). Grades 0-1 were classified as low-risk group, while grades 2-3 were classified as high-risk group. Analysis of variance, Kruskal-Wallis test, and Chi-square test were performed to compare urodynamic results and complications across different grades and groups.

RESULTS

A total of 74 patients were eligible to participate, which included 46 boys (62.2%) and 28 girls (37.8%), the mean age was 75.18 ± 48.39 months. Among them, 11 (14.9%) were PUV, 50 (67.6%) were NB, and 13 (17.5%) were PUV and NB. Significant differences were observed in maximum detrusor pressure, post-void residual urine ratio, and compliance among grades 0-3. Severe hydronephrosis and histories of urinary tract infection were more prevalent in the high-risk group.

CONCLUSION

A reliable grading system with objective standards was proposed which could aid in the assessment of BT severity.