Kidney Function Surveillance in the National Spina Bifida Patient Registry: A Retrospective Cohort Study

The rationale for bladder washouts in children with neurogenic bladder

Children with a neurogenic bladder are at risk of developing recurrent urinary tract infections and long-term kidney failure. Due to an altered lower urinary tract, children may be overtreated for simple bacteriuria or undertreated for a potentially severe urinary tract infection. This group of patients represent high users of healthcare, and are at risk of colonization and development of antibiotic resistance. Bladder washouts with non-antibiotic electrochemically activated solutions are a potential new prophylactic option for patients with bladder dysfunction when clean intermittent catheterization has resulted in chronic bacteriuria.

Stratification of neurogenic bladder risk in spina bifida using the urinary peptidome

Neurogenic bladder poses a major morbidity in children with spina bifida (SB), and videourodynamic studies (VUDS) are used to stratify this risk. This small-scale pilot study utilized current mass-spectrometry-based proteomic approaches to identify peptides or proteins in urine that may differentiate children at high risk of developing renal complications from a neurogenic bladder. Twenty-two urine samples of which nine had high bladder pressure storage that put the upper urinary tract at risk, while 13 with a lower risk for renal compromise were analyzed. More than 1,900 peptides across all 22 samples were quantified, and 115 peptides differed significantly (P < 0.05) between the two groups. Using machine learning approaches five peptides that showed the greatest differences between these two clinical categories were used to build a classifier. We tested this classifier by blind analysis of an additional six urine samples and showed that it correctly assigned the unknown samples in their proper risk category. These promising results indicate that a urinary screening test based on peptides could be performed on a regular basis to stratify the neurogenic bladder into low or high-risk categories. Expanding this work to larger cohorts as well as across a broad spectrum of urodynamics outcomes may provide a useful diagnostic test for neurogenic bladder.NEW & NOTEWORTHY This approach could help risk stratify the neurogenic bladder in patients with spina bifida and could allow us to safely defer on up to 1/3 of urodynamic studies. These pilot data justify a larger trial before this approach becomes a clinical tool.

Medical management of neurogenic bladder in patients with spina bifida: A scoping review

INTRODUCTION

Neurogenic bladder is a common source of morbidity in patients with spina bifida and can cause renal damage. Medical management may include imaging, urodynamic studies (UDS), laboratory testing, clean intermittent catheterization (CIC), and medication. There is ongoing debate regarding the optimal management regimen. Approaches are described by two paradigms: proactive and expectant management. In a proactive approach, invasive interventions like CIC and UDS are initiated before the onset of renal abnormalities. In expectant management, UDS, CIC, and medications are started after abnormalities are identified. In this scoping review, we aim to comprehensively review existing literature on outcomes of proactive and expectant management of neurogenic bladder in patients with spina bifida.

METHODS

We searched multiple databases and screened articles for inclusion using PRISMA-ScR guidelines. Included studies reported clinical outcomes of any aspect of proactive or expectant neurogenic bladder management in patients with spina bifida.

RESULTS

Ultimately, 74 articles were included for review including 67 cohort studies, 4 cross-sectional studies, 2 sequential cohort studies, and 1 randomized control trial. Eleven studies directly compared management strategies. There was substantial heterogeneity in study designs, management protocols, and reported outcomes. Most studies addressed multiple simultaneous aspects of management without specifically analyzing individual aspects. However, some commented on individual aspects of management including UDS (13), CIC (32), imaging (7), and medication (5). Although there was no consensus about optimal management, all direct comparisons of paradigms supported a proactive approach.

CONCLUSION

Our review identified a broad body of literature about optimal management of neurogenic bladder. Existing studies vary greatly in terms of treatment protocols, measured outcomes, and management recommendations. Overall, studies that directly compare management are scarce but favor proactive management. Given the implications on clinical outcomes, it is crucial to focus future work on directly comparing management strategies and isolating the effects of different individual management elements.

Age-based risk of end-stage kidney disease in patients with myelomeningocele

OBJECTIVE

We aimed to quantify end-stage kidney disease (ESKD) risk after infancy in individuals with myelomeningocele (MMC) followed by urology in the modern medical era and to assess if ESKD risk was higher after surgery related to a hostile bladder.

METHODS

We retrospectively reviewed patients with MMC followed by urology at our institution born ≥ 1972 (when clean intermittent catheterization was introduced) past 1 year of age (when mortality is highest, sometimes before establishing urology care). ESKD was defined as requiring permanent peritoneal/hemodialysis or renal transplantation. Early surgery related to hostile bladder included incontinent vesicostomy, bladder augmentation, detrusor Botulinum A toxin injection, ureteral reimplantation, or nephrectomy for recurrent urinary tract infections. Survival analysis and proportional hazards regression were used. Sensitivity analyses included: risk factor analysis with only vesicostomy, timing of surgery, including the entire population without minimal follow-up (n = 1054) and only patients with ≥ 5 years of follow-up (n = 925).

RESULTS

Overall, 1029 patients with MMC were followed for a median of 17.0 years (49% female, 76% shunted). Seven patients (0.7%) developed ESKD at a median 24.3 years old (5 hemodialysis, 1 peritoneal dialysis, 1 transplantation). On survival analysis, the ESKD risk was 0.3% at 20 years old and 2.1% at 30 years old (Figure). This was ∼100 times higher than the general population (0.003% by 21 years old, p < 0.001). Patients who underwent early surgery for hostile bladder had higher ESKD risk (HR 8.3, p = 0.001, 6% vs. 1.5% at 30 years). On exploratory analyses, gender, birth year, shunt status and wheelchair use were not associated with ESKD risk (p ≥ 0.16). Thirty-year ESKD risk was 10% after early vesicostomy vs. 1.4% among children without one (p = 0.001). Children undergoing bladder surgery between 1.5 and 5 years old had a higher risk of ESKD. No other statistically/clinically significant differences were noted.

COMMENT

Patients with MMC remain at risk of progressive renal damage throughout life. We relied on the final binary ESKD outcome to quantify this risk, rather than imprecise glomerular filtration rate formulas. Analysis was limited by few people developing ESKD, inconsistent documentation of early urodynamic findings and indications for bladder-related surgery.

CONCLUSIONS

While ESKD is relatively uncommon in the MMC population receiving routine urological care, affecting 2.1% of individuals in the first 3 decades, it is significantly higher than the general population. Children with poor bladder function are likely at high risk, underlining the need for routine urological care, particularly in adulthood.

Functional level of lesion scale: Validating fourteen years of research with the national spina bifida patient registry

PURPOSE

Functional level of lesion (FLOL) is a grading of the level of neurological function in patients with myelomeningocele and other forms of spina bifida. It has been widely used as an independent variable in studies of spina bifida, but its inter-rater reliability has not previously been tested. The purpose of this study was to measure inter-rater reliability of FLOL testing and compare testing performed by a non-medically trained research associate to testing performed by a pediatric rehabilitation medicine specialist.

METHODS

Children in a multi-disciplinary spina bifida clinic underwent FLOL grading by a non-medically trained research associate. On the same day, these children were also graded by a pediatric rehabilitation medicine specialist. Cohen's weighted kappa statistic was used to compare grading, with the rehabilitation medicine specialist considered the gold standard.

RESULTS

A total of 71 patients participated. FLOL was graded for left and right leg for each participant, resulting in 142 measurements. Cohen's weighted kappa was κ= 0.809, with a standard error of 0.034 and 95% confidence interval 0.723-0.875, indicating substantial agreement.

CONCLUSION

FLOL as measured according to the instructions of the National Spina Bifida Patient Registry by a non-medically trained researcher is a reliable method to grade lower extremity function in spina bifida.

Translating pediatric urodynamics from clinic into collaborative research: Lessons and recommendations from the UMPIRE study group

Pediatric patients present unique challenges in the performance and interpretation of urodynamic studies. Interpretation of urodynamics to guide clinical management at an institutional level is accepted as reliable. Challenges arise however when multi-site collaborations incorporate urodynamics into study design to determine primary or secondary outcomes or to direct decision-making. Although standardized terminology has been established by ICCS, the application of this shared language to performance and interpretation of pediatric urodynamics to across multiple sites may not be intuitive or reliable. With a primary goal of defining the care necessary to protect future renal function, the UMPIRE protocol (Urologic Management to Preserve Initial REnal function) utilizes a urodynamics-based risk stratification to determine medical management for infants with myelomeningocele. Iterative changes in the protocol are based upon the clinical progress of the enrolled children. Despite a team experienced in subtleties of urodynamics and despite efforts to minimize variability across sites, the UMPIRE study group identified several areas in which the language of urodynamics required additional clarification or creation of more explicit definitions to standardize performance and interpretation across sites. This article reviews the foundations of current urodynamics practice, describes limitations and challenges unique to pediatric studies, and the shares the humble lessons learned by the UMPIRE study group on their journey toward standardized urodynamic language for management of infants and children with myelomeningocele.

The Importance of Early Diagnosis and Management of Pediatric Neurogenic Bladder Dysfunction

Neurogenic bladder dysfunction is a major source of urologic morbidity in children, especially in those with spina bifida (SB). Complications from progression of bladder dysfunction can include urinary tract infections (UTIs), urinary incontinence, upper tract deterioration, and renal dysfunction or failure. In these children, there has been a recent trend toward proactive rather than expectant management of neurogenic bladder. However, there is a lack of consensus on how to best achieve the three main goals of neurogenic bladder management: 1) preserving kidney function, 2) achieving continence (if desired by the family/individual), and 3) achieving social and functional urologic independence (if appropriate). Hence, our objective was to perform a narrative literature review to evaluate the approaches to diagnosis and management of pediatric neurogenic bladder dysfunction, with special focus on children with SB. The approach strategies vary across a spectrum, with a proactive strategy on one end of the spectrum and an expectant strategy at the other end. The proactive management strategy is characterized by early and frequent labs, imaging, and urodynamic (UDS) evaluation, with early initiation of clean intermittent catheterization (CIC) and proceeding with pharmacotherapy, or surgery if indicated. The expectant management strategy prioritizes surveillance labs and imaging prior to proceeding with invasive assessments and interventions such as UDS or pharmacotherapy. Both treatment strategies are currently utilized and data have historically been inconclusive in demonstrating efficacy of one regimen over the other. We performed a narrative literature evaluating proactive and expectant treatment strategies as they relate to diagnostics and management of Spina Bifida. From the available literature and our practice, a proactive strategy favors greater benefit in preventative management and may decrease risk of renal dysfunction compared with expectant management.

Integrated Ultrasound With Urodynamics Illustrates Effect of Bladder Volume on Upper Tract Dilation: Should we Trust Surveillance Ultrasounds?

OBJECTIVE

To evaluate if ultrasound during urodynamics (uUS) will show that traditional ultrasound (tUS) routinely underestimates the potential magnitude of upper tract dilation (UTD).

METHODS

Prospective pilot study of 10 consecutive patients ≥ 5 years of age undergoing same day uUS and tUS. Using randomized images, the study pediatric radiologist determined anterior-posterior renal pelvic diameter (APD), bladder volume, vesicoureteral reflux (VUR) and UTD grades. A single pediatric urologist determined urodynamic bladder capacity and assigned either hostile, intermediate, abnormal but safe, or normal national spina bifida patient registry classification (NSBPR).

RESULTS

Bladder volume on tUS was significantly smaller than final bladder volume on uUS (180 vs 363 ml: P<.001). On average, patient reported maximum catheterized/voided volumes were also 82 ml greater than final bladder capacity on uUS. UTD was upgraded in 25% of kidneys and APD increased by 0.6 cm on uUS over that seen on tUS (P=.001). Units with VUR had greater increases in APD (1.2 P=.007 vs. 0.3 cm P=0.06). Changes in APD stratified by NSBPR revealed average increases of up to 1.3 cm.

CONCLUSION

Despite instructions to the contrary, patients come for tUS with a relatively empty bladder as compared to either their urodynamic or patient-reported capacity. This translates to a significant underestimation of UTD with tUS, most notably in those with VUR. Alternatives to traditional protocols include insisting patients wait until their bladder is truly full for tUS, retrograde filling their bladder, or performing uUS. Accurate assessment of UTD severity may help guide long term management.

Urologic guidelines for the care and management of people with spina bifida

PURPOSE

The life expectancy for people with spina bifida has increased, thus resulting in greater need for guidelines in urologic care in order to protect normal renal function, to develop strategies for urinary continence, and to advance independence through adult years.

METHODS

The English literature was assessed from 2002-2015; greater than 300 publications identified. Case reports and opinion pieces were eliminated leaving 100 for in depth review. Clinical questions were then established for each age group that allowed for focused assessment.

RESULTS

There was no Level 1 evidence for any of the defined clinical questions. This resulted in group consensus for all questions throughout all age groups. Guidelines were provided for identifying a symptomatic urinary infection, the role of urodynamic bladder testing and identification of bladder hostility, determining methods of renal function assessment and surveillance, the initiation of continence control, and transitioning to self-care through the teen and adult years.

CONCLUSION

Urologic guidelines continue to be based on clinical consensus due to the lack of high level evidence-based research. Further research is required in all aspects of urologic management. While not the "Standard of Care," these guidelines should be considered "Best Practice".