Male anorectal malformations: presurgical radiologic imaging objective and evaluation

Prone cross-table lateral X-rays (CTLxR) and colostograms play a role in planning surgeries for anorectal malformations (ARMs) without perineal fistulas. 

A new study aimed to establish objective imaging criteria for classifying ARMs.

For this research, male patients with ARMs (2012-2022) were evaluated by three observers using CTLxR and colostograms. The rectal pouch level was estimated using pubococcygeal (PC) and ischiatic (I) lines. The "pigeon sign," characterized by a beak-like image at the end of the rectal pouch on CTLxR, was described and assessed for its diagnostic value. ARMs were categorized as rectobulbar, rectoprostatic, or rectovesical based on pouch location relative to the PC and I lines. Agreement among observers was measured, and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the "pigeon sign" were determined.

Overall, thirteen patients were included. Inter-observer agreement was observed for pouch ending (69.2%), the "pigeon sign" (84.6%), and diagnosis (76.9%) on CTLxR. Concordance between observers and intraoperative diagnosis was moderate (66.6%). The "pigeon sign" demonstrated a sensitivity of 75%, specificity of 100%, PPV of 100%, and NPV of 50%. Colostogram interobserver agreement was 84.6% for pouch ending and 89.7% for diagnosis – with substantial agreement (92.3%) between observers and intraoperative diagnosis.

In conclusion, using PC and I lines along with the "pigeon sign" enhances the analysis of CTLxR and colostograms. These objective methods provide valuable anatomical insights before surgery. They offer reproducibility and accessibility, particularly for less experienced surgeons and radiologists. Accurate execution of radiological studies remains crucial for their proper interpretation and optimal patient care.

Source: Morandi A, Maestri F, Ichino M, et al. Frontiers in Pediatrics.;11:1224620