BACKGROUND:There is wide variation in timing of surgical intervention for classic bladder exstrophy. Timing of initial repair may be dependent on surgeon preference and/or access to care. Safety and efficacy of both newborn and delayed primary closures are well described. However, there is limited understanding of how the bladder and urethral plates change as a child undergoes rapid growth during infancy. In this study, we assessed changes in bladder and urethral anatomy across age at time of closure. METHODS:Through a prospective, multi-institutional exstrophy-epispadias collaborative, intraoperative bladder and urethral plate dimensions were measured prior to primary closure between 2013 and 2024. In this study, only patients with classic bladder exstrophy were included. Preoperative characteristics recorded included: age, sex, institution at which surgery occurred, method of bladder coverage, and exogenous testosterone use. Intraoperatively, number of bladder polyps excised, bladder plate width, height (bladder neck to dome), and depth, bladder neck width (level of longitudinal fibers), urethral plate lengths (bladder neck to tip of glans for males; bladder neck to anterior lip of vagina for females), and maximal urethral plate widths were recorded. Bladder volume was calculated using a hemi-ellipsoid formula. Univariate analyses were performed using t-test and simple linear regression. Multivariable linear regression was used to investigate the association between age at closure and intraoperative variables while adjusting for potential confounders. RESULTS:97 patients underwent primary closure at a median date of 80 days (range 12-208, IQR 44). Clinicodemographic characteristics and intraoperative measurements are summarized in the table. Number of excised polyps (p=0.19), bladder volume (p=0.67), bladder neck width (p=0.27), female urethral plate length (p=0.32), and both male and female urethral plate widths (p=0.34 and p=0.32, respectively) were not associated with age at time of surgery. The number of polyps excised was not associated with method of preoperative dressing (Saran wrap(n=21): 6.9, Tegaderm(n=66): 5.5, p=0.25). Bladder volume at time of closure varied widely, with range of 1.0-40.9 cm3.Male urethral length was associated with age at time of surgery (univariate OR 1.08; 95% CI 1.02-1.13). The association remained significant when controlling for weight and exogenous testosterone exposure (OR 1.13; 95% CI 1.06-1.20). When excluding patients who received exogenous testosterone(n=12), the association remained significant when adjusting for weight (OR 1.13; 95% CI 1.03-1.24). CONCLUSIONS:In patients with bladder exstrophy prior to initial bladder closure, there is significant variability in bladder volume beginning at a young age. However, bladder volume and age are not linearly associated. Delaying surgical intervention and type of preoperative bladder plate dressing were not associated with number of polyps excised. Male urethral length may increase significantly during the first few months of life, independent of exogenous testosterone exposure, likely due to the innate testosterone surge early in life. Further investigations need to be made to identify biologic factors that may promote bladder growth after closure.
| Age at surgery | 80 days (Range 12 - 208, IQR 44) |
| Male | n=66 (68%) |
| Weight | 5.6 kg (Range 2.7 - 8.30, IQR 1.5) |
| Number of Polyps Excised | 5 (Range 1-34, IQR 4) |
| Bladder Volume | 5.3 cm3 (Range 1.1 - 40.9, IQR 5.1) |
| Bladder Neck Width | 2.5 cm (Range 1.3-5.0, IQR 0.9) |
| Urethral Plate Length (Female) | 1.0 cm (Range 0.9-2.0, IQR 0.5) |
| Urethral Plate Length (Male) | 3.7 cm (Range 2.0-5.5, IQR 0.9) |
| Urethral Plate Width (Female) | 1.5 cm (Range 1.0-2.0, IQR 0.4) |
| Urethral Plate Width (Male) | 1.5 cm (Range 1.0-2.5, IQR 0.3) |
