Anal sphincter function after surgery for high imperforate anus--a long term follow-up investigation.

37 children were treated for high imperforate anus during the years 1944-1965. Eighteen of these 37 participated in a follow-up examination at the age of 18-35 years. The examination consisted of an anorectal manometry, EMG of the external sphincter, a digital anal examination, and an interview. Special attention was paid to anal continence. Fourteen patients did not admit any major anal problems, and eight of them had a good continence. Anorectal manometry showed an absence of internal sphincter function in all patients. During voluntary squeeze the continent patients increased anal pressure significantly more than the incontinent ones, and they were also aware of significantly smaller distensions of the rectal ampulla. The present investigation shows the necessity of well-functioning striated sphincter muscles to achieve good continence, and therefore also the importance of careful dissection and identification of the striated sphincter muscles during the operation.