Bladder outlet procedures without augmentation cystoplasty: Long-term outcomes and association of preoperative bladder compliance with subsequent augmentation cystoplasty or urinary diversion and DMSA abnormalities.

Abstract

Background: A bladder outlet procedure (BOP) without augmentation cystoplasty (AC) for incontinence from neurogenic bladder has risks including renal damage and future surgeries.

Objective: Our objective was to obtain long-term outcomes after BOP without AC and identify risk factors for adverse outcomes. We hypothesized that high preoperative bladder compliance is associated with lower risk of subsequent AC or diversion (AC/D) and dimercaptosuccinic acid renal scan (DMSA) abnormalities.

Design: After retrospective review and longitudinal dataset creation, cumulative incidences of outcomes to 15 years were calculated. The association of preoperative bladder compliance with subsequent AC/D and DMSA abnormalities was studied by log-rank test, interval likelihood ratios (ILR), and receiver operative curve analysis.

Results: 119 patients underwent BOP without AC from 2000 to 2022 at median age of 7.4 years (IQR 5.6-11.5). 39 underwent AC during follow up, 4 underwent diversion. Median follow-up was 11.6 years (IQR 7.3-14.1). At 15 years, cumulative incidence of AC/D was 48 % (95 % CI 37-59 %) and DMSA abnormalities was 38 % (95 % CI 29-49 %). For the 85 patients with preoperative urodynamic tracings, ILRs for subsequent AC/D and DMSA abnormality for the 55 % of patients with bladder compliance <15 mL/cm H2O were 2.0 and 1.9. For the 28 % with compliance ≥15 to <35 mL/cm H2O, ILRs were 0.6 and 0.5. The 16 % of patients with compliance ≥35 mL/cm H2O had ILRs of zero for both outcomes. Preoperative bladder compliance was associated with subsequent AC/D (p = 0.004) and DMSA abnormalities (p = 0.015) by log-rank test (Summary Figure).

Discussion: Patients with low preoperative bladder compliance (<15 mL/cm H2O) had high risk of subsequent AC/D and DMSA abnormalities, while patients with high preoperative compliance (≥35 mL/cm H2O) had low risk of these outcomes. There was continued rise in incidence of subsequent AC/D, CKD diagnosis, upper tract changes, and urodynamics with end fill pressure >40 cm H2O from 10 to 15 years after BOP without AC. Limitations include retrospective nature, lack of preoperative DMSA in most, and lack of standardized indications for surgery.

Conclusion: Following BOP without AC, preoperative bladder compliance ≥35 mL/cm H2O was seen in a minority of patients and was associated with low risk of subsequent AC/D and DMSA abnormalities. These results provide practical information for urologists and families for a shared decision making process and support selective use of BOP without AC in patients with high bladder compliance. Long-term monitoring remains important.