Development and validation of a bladder trabeculation grading system in pediatric neurogenic bladder

Bladder height to width ratio as a surrogate marker for non-physiological storage pressures in children with spinal dysraphism

INTRODUCTION

Spinal dysraphism is the most frequent cause of neurogenic bladder. Urodynamic study (UDS) is an important component of the follow-up of a child with neurogenic bladder. However, it suffers from a lack of widespread availability and is further hampered by technical difficulties and difficulty in its interpretation in children. A neurogenic bladder often appears vertically elongated; only limited and sparse literature is available regarding objectively defining the bladder shape and the urodynamic parameters in the cohort.

OBJECTIVES

This study aimed to investigate the usefulness of the bladder's height-to-width ratio (HWR) on cystogram as a screening tool for identifying "non-physiological" bladder pressures in children with spinal dysraphism. A prospective study was undertaken to evaluate children operated for spinal dysraphism. Cystogram, ultrasonography and UDS evaluation were performed. HWR was calculated by the ratio of the maximum height to the maximum bladder width at maximum cystometric capacity (MCC), where MCC was calculated using standard Koff's formula, given by (age in years + 2) *30 ml in children more than one year and weight *7 ml for infants. The children were categorised into groups based on maximum detrusor pressure (MDP) into two groups (MDP ≥ 30 cmH2O and MDP < 30 cmH2O). A receiver-operative characteristic curve was constructed to analyse the sensitivity and specificity of HWR in predicting the MDP.

RESULTS

A total of 53 children, operated for spinal dysraphism, met the study criteria during the study period, from March 2021 to September 2022. The median age of children was 4 years (IQR-3-5.5 years). The HWR ratio was compared between the two groups and was significantly higher for the non-physiological pressure bladders than for physiological pressure bladders (mean of 1.55 vs 1.26, p = 0.001). On evaluating the sensitivity and specificity of HWR for discerning children with non-physiological bladder pressures were 87.5% and 48.28%, respectively. The area under the curve (AUC) was 0.781, with a cut-off value of 1.3.

DISCUSSION

We attempted to evaluate the HWR based on bladder shape objectively. We demonstrated a moderate correlation between the bladder shape and the bladder pressures. An HWR of 1.3 or higher could be significant for identifying a non-physiological bladder storage pressure.

CONCLUSION

The height to width ratio of the bladder on cystogram is a useful tool as a surrogate marker for non-physiological storage pressures in bladders of children with spinal dysraphism.

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.

Home bladder pressure measurements correlate with urodynamic storage pressures and high-grade hydronephrosis in children with spina bifida

BACKGROUND

Patients with spina bifida are at risk for developing bladder and renal deterioration secondary to increased bladder storage pressures.

OBJECTIVES

To determine the association of home bladder volume and pressure measurements (home manometry) to: 1) detrusor storage pressures on urodynamics (UDS); and 2) the presence of Society of Fetal Urology (SFU) grades 3-4 hydronephrosis on renal bladder ultrasound in patients with spina bifida.

METHODS

Data were prospectively collected on patients with spina bifida and neurogenic bladder requiring clean intermittent catheterization. Patients used a ruler and typical catheterization equipment to measure bladder pressures and volumes at home. Home measurements were compared to UDS detrusor pressures and SFU hydronephrosis grade. Detrusor pressure <20 cm H₂O at 50% maximal cystometric capacity (MCC) on UDS was used as a measure of safe storage pressures on UDS; conversely, detrusor pressure >20 cm H₂O was used a measure to capture both unsafe storage pressures and those with potential for unsafe storage pressures. Receiver-operator characteristic curves and area under curve (AUC) were calculated to depict the association between home manometry variables with detrusor pressures on UDS and SFU grades 3-4 hydronephrosis.

RESULTS

Included were 52 patients with a median age of 10.3 years (interquartile range 6.3-14.4 years). Three home manometry measurements (maximum bladder pressure, bladder pressure at maximum catheterized volume, and mean bladder pressure) > 20 cm H₂O were sensitive for Pdet >20 cm H₂O at 50% MCC. Maximal bladder pressure >20 cm H₂O was the most sensitive among home manometry measures (sensitivity 100%, specificity 70%, AUC 0.92 for Pdet >20 cm H₂O at 50% MCC on UDS; sensitivity 100%, specificity 62%, AUC 0.89 for SFU grade 3-4 hydronephrosis). None of the patients who had maximum home bladder pressure <20 cm H₂O had SFU grades 3-4 hydronephrosis; conversely, individuals with maximal home bladder pressure >20 cm had a wide range of hydronephrosis grades.

CONCLUSION

None of the patients with maximal home bladder pressure <20 cm H₂O had grade 3-4 hydronephrosis. Home measurements of maximal bladder pressure, bladder pressure at maximum catheterized volume and mean bladder pressure of >20 cm H₂O were all sensitive for Pdet >20 cm H₂O at 50% MCC on UDS. Home manometry is an inexpensive and simple technique to identify patients at risk for and to monitor individuals at high risk of upper tract dilation, without incurring significant cost or morbidity.

Detection of bladder trabeculation by voiding cystourethrography and sonography: observations in boys with posterior urethral valves

Background

As trabeculated bladder wall is often referred to as a sign of chronically increased intravesical pressure, we investigated whether voiding cystourethrography (VCUG) or sonography reliably predicts bladder trabeculation on later urethrocystoscopy.

Methods

A total of 76 consecutive patients (2012–2017) with cystoscopically confirmed posterior urethral valves (PUV) and pre-endoscopy VCUG were included. Sonography data were available for 68 of these patients. Radiological findings were reassessed and compared with endoscopic findings using Fisher’s exact test and Spearman’s rank assessment.

Results

VCUG showed a sensitivity of 83.3% and a specificity of 30% in predicting trabeculation on a later urethrocystoscopy, with no significant difference in determining mild or severe forms (p=0.51). Sonography proved a sensitivity of 27.6% and a specificity of 70%, with no correlation between sonographic signs and trabeculation on cystoscopy (r=0.1311). In addition, vesicoureteral reflux had no significant influence as a possible pressure pop-off mechanism on the development of trabeculation in our group.

Conclusions

While VCUG predicts bladder trabeculation in children with PUV with limited reliability, sonography mostly fails to detect trabeculation. Therefore, such findings should only be used with utmost caution in relation to clinical decision-making.

Irreversible Bladder Remodeling Induced by Fibrosis

Underactive bladder and impaired bladder compliance are irreversible problems associated with bladder fibrosis. Remodeling of the extracellular matrix is regarded as an important mechanism associated with bladder fibrosis. However, various risk factors and conditions contribute to the functional impairment of the bladder associated with fibrosis, and there is limited knowledge about bladder fibrosis-associated problems in the field of neurourology. Further studies are thus necessary to elucidate the underlying mechanism of bladder fibrosis and to identify effective treatment.

Bladder Volume Assessment in Pediatric Patients With Neurogenic Bladder: Is Ultrasound an Accurate Method?

OBJECTIVE

To define the accuracy of ultrasound to determine bladder volume in pediatric patients with neurogenic bladder (NB).

METHODS

Retrospective analysis of children with NB in treatment with urethral clean intermittent catheterization.

EXCLUSION CRITERIA

bladder surgeries, and catheterization through a channel different than urethra. Bladder volume was measured with ultrasound using the formula: anteroposterior bladder diameter by side to side diameter by distance from dome to outlet tract by 0.523 (cm³). In the same act, the patient was performed urethral catheterization and the drained volume was measured in millimeters. Finally, postvoid residual volume (PVR) was assessed with ultrasound.

RESULTS

We performed 318 measurements in 299 patients, mean age was 9.95 years (standard deviation: 4.6), 59% were female. Most frequent etiologies of NB were myelomeningocele and lipomyelomeningocele. Mean ultrasound-determined bladder volume was 213.9cm3 (range: 20-899 cm³) and mean bladder volume drain through catheterization was 336.4 mL (range: 30-1480 mL; P : .0001). In 67.3% of the patients (n: 214) PVR was not significant, and their mean ultrasound volume was 212.7 mL and the volume evacuated by catheterization was 339.9 mL (P : .0001). In all age groups ultrasound-determined bladder volume was statistically lower than catheterized bladder volume (P : .0001). The mean percentage error of the ultrasound-determined bladder volume was 15.58% ± 44.09. Linear regression analysis and Bland-Altman plot showed low agreement between both measurement techniques.

CONCLUSION

In children with NB, ultrasound-determined bladder volume was statistically lower than catheterized bladder volume measured at the same moment, and this relation persisted regardless of sex, age, and the presence of PVR.