Recent research shows that preoperative bladder compliance can predict adverse outcomes in patients receiving bladder outlet procedures (BOP) without augmentation cystoplasty (AC). Investigators at Children’s Health℠ and UT Southwestern performed the retrospective study, which included more than 100 patients with spinal cord pathology and neurogenic bladder.
The findings: Overall, the team found that using BOP without AC in all patients carries a high risk of adverse outcomes including additional surgery, worsening urodynamic findings and diagnosis of chronic kidney disease.
The nuance: But sorting patients by preoperative bladder compliance revealed more nuance. Specifically, patients with high bladder compliance (≥35 mL/cm H2O) prior to BOP did not develop abnormal renal scans or subsequent AC, while those with low preoperative compliance (<15 mL/cm H2O) had high risk of both outcomes.
“These findings bring clarity to the clinical gray area surrounding when to provide BOP with AC and when it’s safest to provide BOP alone,” says Bruce Schlomer, M.D., Pediatric Urologist at Children’s Health and Professor of Urology at UT Southwestern. “Urologists can now use bladder compliance to stratify patients and advise on treatment.”
Augmentation balances risks of BOP but comes with risks of its own
The surgical options for neurogenic bladder in spina bifida and other spinal cord pathologies come with challenging trade-offs. For children who struggle with incontinence, a bladder outlet procedure can increase their ability to retain urine and avoid leaks. However, greater urine retention can increase bladder pressure and cause upstream difficulties for the kidneys.
To relieve these issues, urologists often supplement BOP with augmentation cystoplasty (AC). AC, however, comes with risks of its own – including bowel obstruction, bowel rupture, bladder stones and bladder leak.
“The job for urologists is to avoid the risks of bladder augmentation when appropriate and perform it, when necessary,” says Dr. Schlomer. “The results from this study help us make these complex decisions with patients and their families.”
Study followed 100+ patients for 10-15 years
The team reviewed records of 119 pediatric patients who underwent BOP without AC from 2000 to 2022. Patients were followed for a median of 11.6 years, and the team calculated cumulative instances of outcomes to 15 years.
Outcomes included subsequent surgeries including AC, development of kidney changes including hydronephrosis and renal scan abnormalities and development of chronic kidney disease (CKD).
This study builds on previous research by the same team, which spanned 2000-2013 and included many of the same patients. That work hinted that preoperative bladder compliance might predict outcomes of BOP without AC but failed to reach a level of statistical significance.
“We reached significance this time with longer follow-up and more detailed urodynamic analysis,” says Alexandra Carolan, M.D., Pediatric Urologist at Children’s Health and Assistant Professor at UT Southwestern.
Patients with ≥35 mL compliance had lowest risk of adverse events
The team identified three ranges of bladder compliance with different levels of risk for future outcomes:
High preoperative compliance (≥35 mL). No patients in this range underwent subsequent AC or diversion (AC/D) within the study period or developed abnormal renal testing results. Only 16% of patients in the study fell into this group.
Intermediate compliance (≥15 mL to <35 mL). Patients in this range comprised 28% of the total cohort and had intermediate risks of AC/D and abnormal renal function.
Low compliance (<15 mL). More than half of patients (55%) fell into this group, which had the highest risk for AC/D and abnormal renal function.
Urologists can use these ranges to advise patients on treatment options. The group at Children’s Health and UTSW now consider BOP alone for patients with high compliance (few cases), BOP with AC when compliance is low (most cases), and use shared decision making in the patients with intermediate preoperative bladder compliance.
“In my opinion, patients with low compliance – the majority in our study – are likely better off getting augmentation right away based on these results,” says Dr. Schlomer.
High rates of CKD and future surgery overall
Overall, 15-year cumulative estimates for the entire patient cohort showed very high rates of adverse events:
AC/D: 48%
Additional continence procedures: 60%
CKD stage 2 or higher: 46%
These outcomes align with previous research and underline why urologists should be selective about offering BOP without AC.
A majority of pediatric urologists may already take that approach. For them, the new evidence confirms their position and provides clear thresholds to work by.
But some in the field find AC to be the riskier proposition, given the numerous complications, and provide BOP by itself more frequently. The patients in this study demonstrate possible consequences of this approach. Nearly half ended up receiving AC at some point anyway, and a comparable share developed kidney disease.
Based on the results of this study, urologists who favor BOP without AC for all patients may reconsider their algorithms for who is eligible. Using bladder compliance as a guide, they may match patients with more appropriate care and help them avoid long-term complications.
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