Anorectal Malformations

Explanation

The priority in a newborn with suspected imperforate anus is a systematic evaluation to determine the type of malformation (high vs. low) and to screen for associated life-threatening VACTERL anomalies. The initial step is to transfer the baby to a monitored setting (like the NICU) for evaluation. A cross-table lateral radiograph (the "invertogram" or prone cross-table lateral) taken after 24 hours of life (to allow air to reach the distal rectum) helps estimate the distance between the rectal pouch and perineum, guiding initial surgical planning. Option A is a subsequent study done after colostomy. Option C is contraindicated without defining the anatomy first, as a blind incision could damage the sphincter complex. Option D is incorrect as this is a surgical condition requiring immediate attention.