Rectal prolapse is a protrusion of rectal wall tissue through the anus. In a normal individuals, rectal prolapse does not occur because the rectum is anchored to the pelvic structures by suspensory mechanisms of the normal rectum. Patients with anorectal malformations represent a spectrum of defects, that ranges from patients born with benign defects, good functional prognosis and almost normal sphincters who rarely suffer from rectal mucosal prolapse to these that are born with complex malformations, poor functional prognosis, poorly developed pelvic structures, poor or absent sphincters, poor nerves and, in general, poor mechanisms of suspension of the rectum.
The rectal prolapse is problematic because it produces wetness (mucus produced by the rectal tissue), which can pass through the underwear and the clothes of the patient. Also, when the child is very active the prolapsed rectal tissue can be injured, and may bleed.
Also, when the prolapse remains constantly outside the rectum, it can produce fecal incontinence. To explain this, one must remember that bowel control (fecal continence) depends on three factors: A) sensation at the anal canal and rectum, B) sphincter function, the ability to squeeze closed the anus by surrounding muscles and C) colonic motility. To have bowel control, one must feel what is inside the rectum. The most sensitive part of our rectum resides within the last 3 or 4 cms of the rectum, near the skin. This portion is called the anal canal. When a prolapse occurs, the rectal contents (stool) do not touch or distend the sensitive area (anal canal) and therefore it is not felt by the patient. Also, the sphincters cannot fully close the anal canal because of the protruding rectal tissue. Therefore, in a patient with anorectal malformations, a rectal mucosal prolapse can interfere with bowel control, even if the patient was born with a good prognosis type of malformation.
Many patients with anorectal malformations receive a colostomy at birth, followed by the main pull-through and subsequently, (after the patient has undergone a protocol of anal dilatations), the patient undergoes the last operation which is the colostomy closure.
The operation for rectal prolapse takes approximately 45 minutes and consists in resecting the extra tissue, and resuturing the rectal wall to the skin of the periphery of the anus. The operation is painless, and the patient can be discharged the same day. Two weeks after the operation, the patient is again subjected to the same protocol of anal dilatations, and thereafter, the colostomy is closed. It is extremely unusual for a prolapse to come back after an operation like this.
It is very important for the parents to know that rectal prolapse can be worsened when the patient remains for long periods of time sitting on the toilet. This is particularly common in patients suffering from constipation. This is one of the many negative effects of constipation and therefore, constipation must be treated proactively and aggressively. Patients with anorectal malformations often need to receive laxative foods or laxative medications, enough to make their bowel movements quick and easy episodes.