Anatomic factors predict urinary continence in patients with anorectal malformation
Molly E. Fuchs, MD, Devin R. Halleran, MD, Yuri Sebastião, PhD, Laura Weaver, RMA, Hira Ahmad, MD, Christina B. Ching, MD, Marc A. Levitt, MD, Richard J. Wood, MD, Daniel G. Dajusta, MD.
Nationwide Children's Hospital, Columbus, OH, USA.
Background: In patients with anorectal malformation (ARM) the use of the ARM index, which incorporates ARM subtype, sacral ratio and type of spinal abnormality, has been used to predict the chance for fecal continence. However, no studies have investigated if any of these anatomic factors that make up the ARM index can predict urinary continence. The purpose of this study was to identify anatomic factors associated with urinary continence in children born with ARM.
Methods: A retrospective review of a large prospectively collected database of children with ARM was performed. Inclusion criteria included diagnosis of ARM, age > 4 years, available lateral sacral ratio measurement and MRI spinal cord imaging available for analysis. Any child with a colostomy, incomplete data or no continence data was excluded. Continence was defined as voiding per urethra volitionally, dry between voids and ≤ 1 urinary accident per week. Bivariable tests of association and log-binomial regression models were used to examine association between anatomic factors and urinary continence.
Results: A total of 434 patients were included in the study. 57.8% (n = 251) were male. Median age was 8.4 years (IQR 6.0 – 12.3). With regards to severity of ARM, 20.3% (n = 88) were high, 23.3% (n=101) were intermediate and 56.5% (n = 245) were low. Lateral sacral ratio included 11.1% (n = 48) that were < 4%, 36.2% (n=157) were 0.4 – 0.6% and 52.8% (n = 229) were > 0.7%. Spine status was 4.4% (n = 19) myelomeningocele, 34.8% (n = 151) with low conus/tethered cord and 60.8% (n = 264) with only a fatty filum/normal spine. Overall 62.2% spontaneously void per urethra and were dry between voids and were therefore, continent. On univariate analysis and multivariable analysis, the anatomic factors of ARM severity, lateral sacral ratio and spine status are each independent predictors or urinary continence in this population. The multivariable results are summarized in Table 1.
Conclusion: In children born with ARM, low severity ARM, high sacral ratio and normal spine are all independently predictive of higher chance of urinary continence. This is important because these anatomic factors that make up the ARM index are congenital and are not impacted by prior surgery or other iatrogenic factors. This data is critical in counseling families of these complex children about reasonable expectations with respect to urinary continence.
Table 1. Prevalence Ratios of urinary continence by patient anatomic factors
Patients (n) | Continent, %(95% CI) | Unadjusted Prevalence Ratio (95% CI) | P | Adjusted Prevalence Ratio (95% CI) | P | ||
Severity of ARM, n (%) | Higha | 88 | 31.8 (22.1-41.6) | 0.42 (0.31-0.58) | <.0001 | 0.50 (0.37-0.68) | <.0001 |
Intermediateb | 101 | 57.4 (47.8-67.1) | 0.76 (0.64-0.92) | 0.004 | 0.81 (0.68-0.96) | 0.013 | |
Lowc | 245 | 75.1 (69.7-80.5) | 1.00 | Reference | 1.00 | Reference | |
Lateral sacral ratio categories, n (%) | <0.4 | 48 | 31.2 (18.1-44.4) | 0.47 (0.31-0.72) | 0.001 | 0.62 (0.41-0.94) | 0.026 |
>=0.4 | 386 | 66.1 (61.3-70.8) | 1.00 | Reference | 1.00 | Reference | |
Spinal cord/Spine/Sacral findings, n (%) | Low conus/Tethered cord/Myelomeningocele | 170 | 44.7 (37.2-52.2) | 0.61 (0.51-0.73) | <.0001 | 0.69 (0.58-0.82) | <.0001 |
Fatty filum/Normal | 264 | 73.5 (68.2-78.8) | 1.00 | Reference | 1.00 | Reference | |
Continent: Dry and spontaneous voiding through the urethra; Unadjusted estimates were obtained from a univariable model that include each variable shown as a single predictor; Adusted estimates were obtained from a multivariable model that included all variables shown. | |||||||
aHigh: (Cloaca>3cm, Cloacal exstrophy, Rectobladderneck)bIntermediate: (Rectoprostatic, Rectovaginal, Cloaca<3cm)cLow: (Perineal, Rectobulbar, Rectovestibular, Imperforate anus, Anal stenosis, Rectal atresia, H type fistula) |
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