Internal anal sphincter achalasia in chronic functional constipation in children: A myth rather than reality

Internal anal sphincter achalasia (IASA) is characterised by chronic constipation and it is diagnosed based on an absent rectoanal inhibitory reflex (RAIR) on manometry despite a ganglionated rectal biopsy. This study evaluates the pathophysiology of IASA in children with chronic functional constipation (CFC) and determines whether it represents a distinct disorder or a functional variant of constipation.