Introduction: Anal atresia, apparent at birth, is temporized by perinatal diverting colostomy.  Definitive surgical repair approach is determined by distance from the blind-ending rectal pouch to the anal dimple and presence/absence of a fistula. It is imperative that a preoperative diagnostic procedure, an augmented-pressure distal colostogram, be performed with meticulous attention to technique to inform the surgeon’s approach decision. We present a case that demonstrates how to perform the augmented-pressure distal colostogram correctly to avoid pitfalls that could prolong surgery time, recovery time, or negatively affect long term outcome.

 

Case Presentation: History/Physical: A 50-day-old male with anal atresia without clinically apparent rectourethral/rectoperineal fistula was treated with diverting colostomy shortly after birth. Surgeon consulted radiologist for surgical planning assistance.

 

Differential Diagnosis:  Anal atresia with high vs. low positioned rectal pouch with/without rectal fistula.

 

Results: Definitive diagnostic exam is an augmented-pressure distal colostogram. It demonstrated a low rectal pouch inferior to sacral tip and small caliber rectoperineal fistula.

 

Discussion: Anal atresia treatment begins with diverting colostomy with mucous fistula to the rectal pouch shortly after birth as a temporary measure until definitive surgical repair at 4-6 weeks old. The rectal pouch distal end position relative to the sacral tip and the presence/absence of a fistula determine definitive surgical approach: either posterior approach sagittal anorectoplasty (PSA) alone or PSA plus anterior approach via laparoscopy. Radial hydrostatic pressure must be provided to the pouch for proper distention to accurately determine the rectal pouch position relative to the anal dimple and whether a fistula is present.  Meticulous detail to balloon inflation inside the mucous fistula, true lateral positioning of the infant with the legs flexed and adequate filling of the rectal pouch are required.

 

Diagnosis:  A diagnostic quality augmented-pressure distal colostogram assisted the pediatric surgeon in determining that a PSA alone with rectoperineal fistula takedown was the optimal surgical approach to correct the rectoperineal fistula and the anal atresia. VCUG was performed prior to colostomy takedown.

 

Conclusion: Consultation between the surgeon and the radiologist to assure performance of a diagnostic quality augmented-pressure distal colostogram allows individualized surgical planning in each infant with anal atresia.

 

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2. Cho S, Moore SP, Fangman T. One Hundred Three Consecutive Patients with Anorectal Malformations and Their Associated Anomalies. Archives of Pediatrics & Adolescent Medicine. 2001 May 1;155(5):587-91.
3. Singh M, Mehra K. Imperforate Anus. InStatPearls [Internet] 2021 Aug 30. StatPearls Publishing.
4. Kraus SJ, Levitt MA, Peña A. Augmented-Pressure Distal Colostogram: The Most Important Diagnostic Tool for Planning Definitive Surgical Repair of Anorectal Malformations in Boys. Pediatric Radiology. 2018 Feb;48(2):258-69.