Ileoanal reservoir surgery or ileoanal anastomosis is a two-stage restorative procedure that removes a part of the colon and uses the ileum (a section of the small intestine) to form a new reservoir for waste that can be expelled through the anus.
This surgery is one of several continent surgeries that rely upon a newly created pouch to replace the resected colon and retain the patient’s sphincter for natural defecation.
Ileoanal reservoir surgery is also called a J-pouch, endorectal pullthrough, or pelvic pouch procedure.
A number of diseases require removal of the entire colon or parts of the colon. Proctolectomies (removal of the entire colon) are often performed to treat colon cancer.
Another surgical option is the creation of an ileoanal pouch to serve as an internal waste reservoir—an alternative to the use of an external ostomy pouch.
An ileoanal reservoir procedure is performed primarily on patients with ulcerative colitis, inflammatory bowel disease (IBD), familial polyposis, or familial adenomatous polyposis (FAP), which is a relatively rare cancer that covers the colon with 100 or more polyps.
FAP is caused by a gene mutation on the long arm of human chromosome 5. Ileoanal reservoir surgery is recommended only in those patients who have not previously lost their rectum or anus.
The prevalence of familial adenomatous polyposis (FAP) in the United States is two to three cases per 100,000 persons. It develops before age 40 and accounts for about 0.5% of colorectal cancers; this figure is declining, however, as more at-risk families are undergoing detection and prophylactic colon surgery.
The annual incidence of ulcerative colitis is 10.4–12 cases per 100,000 people. The prevalence rate is 35–100 cases per 100,000.
People of Jewish descent have two to four times the risk of developing ulcerative colitis than people from other ethnic backgrounds. About 20% of ulcerative colitis patients require surgery of the colon.
Conventional ileoanal reservoir surgery is an open procedure that is done in two stages. In the first stage, the surgeon removes the diseased colon and creates a pouch.
The second stage is performed three months later, when the temporary drainage conduit is closed and the newly created reservoir allows the patient to defecate in the normal fashion.
Both surgeries can also be done together, bypassing the creation of a temporary ileostomy .
Some surgeons use a laparoscopic approach to ileoanal surgery. This technique involves the insertion of scaled-down surgical instruments and a scope that allows the surgeon to see inside the abdomen through several relatively small incisions (3.5 inches [9 cm] or about compared to 6.3 inches [16 cm] or for an open procedure) in the abdominal wall.
Studies indicate that there are few differences in the rates of mortality or complications between laparoscopic surgery and conventional open surgery.
Because the incisions are smaller, patients typically require less pain medication with laparoscopic surgery.
Ileoanal surgery includes the following steps:
- The surgeon isolates the ileum or small segment of bowel.
- The segment is then attached to the anus with absorbable sutures.
- A pouch is created out of the small bowel above the anus.
- If the surgeon is performing the procedure in two stages, he or she creates a temporary ileostomy. An ileostomy is a tubular bowel segment attached to a stoma at the abdomen that drains into a bag outside the abdomen.
In the second-stage operation, the surgeon uses an open abdominal procedure to close the temporary pouch.
The surgeon will insert stents to bypass the surgical site and divert urinary and digestive wastes to the outside of the body, thus allowing the new connection between the ileum and the anus to heal properly.
Who is a candidate for the procedure?
This surgical procedure is an option for most individuals with ulcerative colitis (UC) or familial adenomatous polyposis (FAP). The creation of the reservoir can involve multiple operations.
A period of adjustment to the “normal” functioning of the completed reservoir is required. This may involve some minor lifestyle changes.
Adaptation to the reservoir can take 6-12 months. Patient motivation will add to the success of the procedure.
In general, the IAR procedure is not considered an option for patients with Crohn’s disease or those who have poorly functioning anal sphincters.
Patients with indeterminate colitis (where a definite diagnosis of either Crohn’s disease or ulcerative colitis cannot be made) may be candidates for the IAR, but the failure rate for the procedure is higher for those with indeterminate colitis than UC.
Older patients may also have the operation, but may be considered poor candidates. Concerns with older patients include the potential for poor post-operative function of the reservoir (including incontinence) and complications during the operation.
Your surgeon will review whther this surgery is appropriate for you.
What is involved in the ileo-anal reservoir (IAR) operation?
The IAR procedure requires one, two, or three operations (stages) to remove the large bowel and the rectum, and to create a new reservoir. Determining whether your IAR can be done in one, two or three stages is dependent upon:
- how healthy you are at the time of your operation,
- whether you have been on any medications that may increase your risk for complications (like steroids),
- the surgeon’s judgement as to which procedure will work best for you, and
- your underlying disease (UC, indeterminate colitis, or FAP).
For most people, the IAR is done in two stages.
The diagnosis of FAP is usually made after symptoms caused by polyps in the colon, such as rectal bleeding, diarrhea, and abdominal pain, have led to a physical examination , the taking of a family history, and in some cases a genetic test.
Ulcerative colitis or inflammatory bowel disease patients have usually been treated with medical alternatives before they decide to have surgery.
All patients who are candidates for an ileoanal procedure will have an evaluation of the upper gastrointestinal tract, an x ray of the small bowel, and a colonoscopy with a pathology review.
Most patients will also be given a sigmoidoscopy and a digital rectal examination.
The surgeon will need to perform an ileostomy in about 5–10% of cases because the patient’s rectal muscles are not strong enough for an anastomosis.
This possibility is discussed with the patient, as well as the fact that complications in surgery may lead to an ostomy procedure. The placement of a stoma must be decided in the event that an ileostomy is necessary.
The physician evaluates the patient’s abdomen while the patient is sitting and then standing, in order to avoid placing the stoma inside a fatty fold of the abdomen.
A stomal therapist is often called in to prepare the patient for the possibility that an appliance will be needed. In addition to the medical and surgical considerations of the procedure, the patient requires psychological preparation regarding the changes in function and appearance that accompany this surgery.
Prior to surgery, the patient must undergo a bowel preparation, which includes a clear-liquid diet for two days before the procedure.
In addition to drinking nothing but clear fluids, the patient must have a cleansing enema until the bowel runs clear.
The importance of a thorough bowel preparation must be explained to the patient, because leakage from the bowel during surgery can be life-threatening.
Open ileaoanal reservoir surgery is a lengthy procedure (as long as five hours) with a slow recovery rate (approximately six weeks) and a relatively long stay in the hospital (about 10 days). The catheters and stents that were used are removed several days after surgery.
The patient will be introduced to a special diet in the hospital, and the diet will be altered if needed in response to changes in the chemistry of the colon.
The patient’s stools are measured, and he or she is monitored for dehydration. In addition, the patient will have the opportunity to discuss his or her concerns about care of the new reservoir and frequency of defecation with staff members before leaving the hospital.
For carefully selected patients this procedure, developed over 30 years, is the preferred form of radical colon surgery when the patient’s sphincter and rectum are still intact.
The advantage of the ileoanal reservoir surgery is that the patient has an internal pouch for the collection of waste material and can pass this waste normally through the anus. Bowel movements may be more fluid, however, and more frequent with the new reservoir.
In a small percentage of cases, the surgeon may eventually need to perform an ileostomy due to complications.
In one quality of life study for patients who have undergone ileoanal reservoir surgery, researchers found only slight differences in their general health and level of daily activity compared with subjects recruited from the general population.
Morbidity rates with this procedure have decreased over time due to improvements in technique. The most common complication is inflammation of the pouch, which occurs in as many as 40% of patients. This complication can be treated with medication.
Other complications include severe scarring around the incision, and some risk of injury to the nerves that control erection and bladder function.
In one major study of 379 patients, researchers at the University of Cincinnati reported that 79 patients had pouch infections (24.3%) and another 20 patients required further surgery for obstructions of the small bowel (6.2%).
The major surgical alternative to an ileoanal reservoir procedure is an ileostomy. In an ileostomy, the patient’s fecal matter drains into a plastic bag attached to a stoma on the outside of the patient’s abdomen or into a pouch attached to the abdominal wall to be withdrawn through a plastic tube.