Defaecation problems in children: anatomy, physiology and pathophysiology of the defaecation mechanism.

Disturbed defaecation mechanism in children is an underestimated problem. On the one hand because many are unaware that children too may have serious defaecation problems, on the other hand due to ignorance of the anatomy and the physiology of the congenital malformations of the defaecation mechanism, such as anorectal malformations and Hirschsprung's disease. The notion that after operative correction the defaecation mechanism will function normally again is incorrect, for the surgical techniques have their limitations, and at postoperative check-up subjective feelings often obscure correct observation. Objective registration methods, morphological and functional tests that may elucidate the defaecation problem, are not being used to their full advantage. Two case histories illustrate the correlations between the anatomical structures of the defaecation mechanism, the functions of these structures, the history and physical examination of the patient, and defaecography and anorectal manometry. History and physical examination should be considered subjective registration methods, defaecography and anorectal manometry objective methods. After scrupulous evaluation of the recorded data it will appear to be possible to decide on the most suitable treatment and guidance.