Preservation of renal function in the modern staged repair of classic bladder exstrophy

Objective: To compare the estimated glomerular filtration rate (eGFR) in bladder exstrophy patients with published normative GFR estimates. Patients and methods: eGFR was calculated using the Schwartz formula at three timepoints, with mean eGFR at each timepoint compared to normative values. Results: At primary closure (n = 53) the mean eGFR (ml/min/1.73 m²) in exstrophy patients was similar to norms at 0-7 days (exstrophy vs norm: 42.5 vs 40.6, p > 0.05) and after 2 years of age (108.8 vs 133, p > 0.05). However, the mean eGFR in exstrophy patients was significantly lower than norms between 8 days (44.8 vs 65.8, p < 0.0001) and 2 years of life (68 vs 95.7, p = 0.01). At bladder neck reconstruction (n = 13) no statistically significant difference existed between the exstrophy and normative eGFR values (137.1 vs 133, p > 0.05). Similarly, among 27 patients with at least 1 year follow-up after bladder neck reconstruction, the mean exstrophy eGFR was no worse or higher than normative values (2-12 years: 124.5 vs 133, p > 0.05; males ≥13 years 175.6 vs 140, p = 0.04; females ≥13 years 128.8 vs 126, p > 0.05). Conclusion: The staged reconstruction of exstrophy does not appear to negatively impact renal function in most patients. As eGFR detects only significant changes, surgical reconstruction may still cause more subtle renal damage.