Correlation of anorectal malformation complexity and associated urologic abnormalities

Patients with anorectal malformations (ARM) commonly have associated urologic anomalies. Few large studies exist to accurately characterize the incidence or associations between severity of malformation and urologic diagnosis. The purpose of our study was to determine the incidence of urologic diagnoses in a large cohort of children with ARM and evaluate for any correlation between severity of ARM and the incidence and number of associated urologic diagnoses.

A retrospective review was performed of patients with ARM treated at our pediatric colorectal center. All patients underwent protocolized urologic screening. ARM subtypes were ordered with increasing severity as follows in males: perineal, bulbar, prostatic and bladder neck fistulae. Females were similarly categorized as perineal, vestibular and vaginal fistulae followed by cloaca with <3 cm common channel and cloaca with >3 cm common channel. The following urologic diagnoses were assessed to determine whether a correlation existed with the severity of the ARM subtype: hydronephrosis, vesicoureteral reflux (VUR), solitary kidney, renal ascent anomalies (ectopic or pelvic), renal fusion anomalies (horseshoe or cross fused kidney), duplex kidney, hypospadias and undescended testicle. ARM subtypes were defined by distal rectal anatomy.

A total of 712 patients were included in our study with a mean age of 4 years and of whom 45% were male. The overall rate of urologic anomalies was greater in males than females (65% vs 56% p < 0.026). In both sexes, the rate of urologic anomalies increased with increasing severity of ARM subtype (p<0.00010) finding that males with bladder neck fistula and females with cloacal malformations, particularly with long common channels, being the highest incidence. In males and females, the rate of hydronephrosis increased as the complexity of ARM increased and this correlated significantly (p < 0.0001 vs p < 0.0003 respectively). Similarly, the incidence of VUR also increased as complexity of ARM increased in both males and females (p = 0.01 and p<0.0001 respectively). The remaining urologic diagnoses were not significantly correlated with severity of ARM.

Urologic anomalies occur at a high rate in children with ARM and appear to increase in frequency with increasing complexity of ARM subtype. These findings stress the importance of proper ARM screening and proactive collaboration with a clinician with expertise in pediatric urology early in the management of such children to improve early recognition of urologic diagnoses.

Level III.