Patients with imperforate anus and a perineal, cutaneous fistula have the opening of the latter situated between external genitalia and the site of the external anal sphincter.
Perineal inspection reveals:
- a 'bucket handle' skin tag
- a meconium-filled, black subepithelial area representing the fistula
- an anal dimple
Repair in both sexes involves a minimal posterior sagittal anoplasty at 3-4 months of age. The rectum is partially dissected and then moved to the region of the external sphincter. The formation of a protective colostomy is not required.
Prognosis for return of function is excellent, but intermittent constipation remains a residual problem in most cases. It is treated prophylactically.