WOFAPS 2025 8th World Congress of Pediatric Surgery

Judith Lindert, Daniel Erkel, Edyta Schmidt, Stefanie Märzheuser

Department of Paediatric Surgery, University Rostock

Purpose
Children with congenital colorectal disorders like Anorectal Malformation (ARM) or Hirschsprung Disease (HD) often face constipation or soiling after surgery. Bowel management (BM) is key for achieving continence and is typically monitored via repeated abdominal X-rays, despite concerns about radiation exposure in young children. X-rays are still used for assessing fecal load in functional constipation (FC), though their value is limited and not guideline-recommended. Abdominal ultrasound has emerged as a safe alternative, but data for ARM and HD are lacking. This study evaluates Point-of-Care Ultrasound (POCUS) measurement of transverse rectal diameter (TRD) for monitoring BM in these patients.

Methods
A prospective case-control study (04/2023–04/2024) included children with HD, ARM, and FC, plus controls without abdominal symptoms. TRD was measured using the Klijn method with a curved probe angled ≥15° over a moderately full bladder. Fecal load was assessed retrogradely, with follow-up at 1, 3, and 6 months. Clinical data were collected from records. Sample size was calculated a priori; analysis was performed using SPSS 26.0.

Results
Post-surgical ARM and HD patients (excluding total colonic aganglionosis) showed significantly increased TRD with constipation or soiling, similar to findings in FC. TRD decreased with successful BM (p < 0.05). Sensitivity was 95.89%, specificity 72.84%. Controls showed no rectal fecal load; asymptomatic cases had minor colonic load. TRD strongly correlated with fecal load (p < 0.0001) and was sufficient for BM monitoring, without needing X-rays.

Conclusion
POCUS is a reliable, radiation-free tool for assessing fecal load and managing BM in children with or without colorectal pathology. A TRD cut-off of 3 cm effectively distinguishes symptomatic from asymptomatic children. This is the first study to validate its use in ARM and HD patients.