Assessment of the percentages of maximum static pressure in the anal canal for postoperative continence in patients with imperforate anus.

The maximum static pressure in the anal canal was measured using an open-tip manometric method with a continuous infusion system. The values obtained from 49 postoperative patients with imperforate anus were expressed as a percentage of those values obtained from 108 aged-matched controls. The value was observed to be 50 per cent or more in those patients with translevator type, showing normal defecation, 30-50 per cent in those with supralevator type, showing normal defecation or constipation, and 30 per cent or less in those with supralevator type, showing incontinence, and 30 per cent or less in those who had undergone surgery on the anal area at another hospital and required re-operation at our department, showing normal continence or incontinence.