We describe the physiological examination of anorectal function in children with chronic constipation (CC), including Hirschsprung's (H) disease (aganglionosis) and its allied disorders [hypoganglionosis (Hypo) and intestinal neuronal dysplasia (IND)]. The assessments are summarized as follows: 1) Anorectal manometry: Enteric nervous system, especially non-adrenergic non-cholinergic excitatory and inhibitory nerves, controls the ano-rectal sphincter reflex. Therefore, patients with aganglionosis lack ano-rectal sphincter reflexes. Abnormalities of the enteric nervous system in Hypo and IND show atypical sphincter reflexes. In contrast, CC patients exhibit normal sphincter reflexes. 2) Terminal motor latency in the pudendal and sacral nerves: Patients with aganglionosis, Hypo, IND and CC exhibit conduction delay of these nerves. These findings may suggest damage to the pudendal and sacral motor nerves due to straining during defecation. 3) Anal canal sensation test (anal canal mucosal electrosensitivity and somatosensory evoked potential tests): Anal sensation is decreased in patients with H disease, Hypo, IND and CC. These findings may suggest damage to the pudendal sensory nerves due to straining during defecation. 4) Defecography: This examination easily detects an obstructive type in school-age patients with CC. 5) Gastrointestinal transit time: This examination easily detects the slow transit type in school-age patients with CC. Conclusions: It is easy for pediatric surgeons to evaluate physiological function in patients with CC, H disease and its allied diseases using physiological examinations.
