What is an ileal pouch?
In some cases of colorectal disease, such as chronic ulcerative colitis, familial adenomatous polyposis (an unusually large number of polyps in the colon), or colorectal cancer, all of the colon and rectum (large intestines) must be removed using a surgery called a total proctocolectomy.
After surgical removal of the large bowel, which absorb liquids and then stores and eliminates solid wastes, patients may be candidates for an ileal pouch-anal anastomosis (IPAA) procedure to provide a new way to store and pass stools the normal way, without a permanent bag.
The term “anastomosis” means a joining together of disconnected parts, like joining two pipes. In the case of an IPAA, the ileum (lowest part of the small intestine) is formed into a new reservoir to store solid wastes. This reservoir or pouch is connected to the anus to provide for elimination the normal way. The pouch enables the patient to store and pass stool through the body’s usual route, so that the patient doesn’t need an external bag to collect waste.
There are three different types of ileal pouches: J-pouch (the most common type), S-pouch, and the K-pouch. The J-pouch and S-pouch resemble the letters in the their names.
In order to have an ileal pouch procedure, the patient’s intestines, anus, anal sphincter muscles, and pelvic nerves must still be able to function normally. This will allow the person to maintain control of bowel movements once a pouch is constructed, and avoid bowel accidents.
How are the different types of pouch surgeries performed?
A J-pouch is made by using two loops of small intestine, each measuring about 8 inches long (20 cm each). The pouch is connected to the top of the anus to allow for elimination of waste matter. After the pouch is constructed, it holds the stool, which is not solid, until the patient is ready to use the bathroom. This is called the ability to defer defecation. Most people who have a J-pouch move their bowels approximately 7 times a day, some once at night, and most don’t have problems with accidents.
The J-pouch is the type that is used most often because it requires a shorter length of intestine than other pouches, is the easiest of the pouches to make, and is highly effective. J-pouch procedures are the preferred method for treating cases of chronic ulcerative colitis in which symptoms are hard to control with medications, or for patients who develop polyps or cancer. J-pouches are also used in cases of familial adenomatous polyposis, and sometimes for colon and rectal cancers.
It usually takes two or three operations to make the J-pouch, and almost all patients will have a temporary ileostomy bag for 3 to 9 months while the new J-pouch heals. Patients who cannot or should not have a J-pouch may need a permanent ileostomy.
The S-pouch is made in a similar way as the J-pouch, except it has a 1-inch (2-cm) “out-spout” of small intestine below the pouch that is attached to the anal canal (using the same technique as the J-pouch). An S-pouch is usually made if the surgeon finds that the J-pouch cannot reach the top of the anus. An S-pouch may be used to help a new (redo) pouch reach if the previous pouch has complications and doesn’t work properly.
Three loops of small intestine, each about 6 inches in length (about 15 cm each), are used to make the S-pouch. The pouch is able to hold from one-half to one pint of fluid. As with the J-pouch, it usually takes two or three operations to make the S-pouch, and almost all patients will have a temporary ileostomy bag for 3 to 9 months while the new S-pouch heals. Patients who cannot or should not have an S-pouch may need a permanent ileostomy.
Some patients who have an S-pouch have trouble completely emptying the pouch. These patients have to clear the pouch with intubation (inserting a tube into the pouch through the anus). It should be noted that this procedure is not done often currently.
K-Pouch (also known as a Kock Pouch or Continent Ileostomy)
Most patients who cannot have a J- or S-pouch will have a permanent ileostomy bag. However, the Kock pouch, or K-pouch, is an alternative to a regular (end) ileostomy. The K-pouch is used in cases of ulcerative colitis when the large intestine and rectum need to be removed because of disease and the anal sphincter muscles are weak, or because a J- or S-pouch cannot or should not be made.
About 16 inches (40 cm) of the last portion of the small intestine are used to build an internal reservoir, which is then attached to the inside of the abdominal wall. A small opening called a stoma leads out and is used several times a day to drain waste matter through a catheter (tube) inserted into the K-pouch.
Three loops of the small intestine, each about 12 inches long (about 30 cm), are stitched or stapled together to form the pouch. Another length of intestine, approximately 4 inches (about 10 cm), is used to make a valve or “nipple” between the stoma and the pouch. The nipple acts as a flap valve to keep waste and gas inside the pouch until the patient drains it with a tube. When stool and gas build up inside the pouch, the flap is pushed shut to prevent leakage.
The main advantages of the K-Pouch over a regular ileostomy are that:
- The patient does not require a bag.
- The stoma is covered with a gauze pad, Band-Aid, or “mini-bag.”
- The patient chooses when to empty his or her bowels.
The main disadvantages of the K-pouch are that:
- The procedure is rarely performed.
- The re-operation (revision) rate is around 50%.
- If the K-pouch needs to be removed, the patient loses more small intestine relative to the other kinds of pouches.
Recovery and Outlook
What can be expected after ileal pouch surgery?
In most cases after ileal pouch surgery, quality of life improves over time. Patients can usually resume normal work and activities about 4-8 weeks after surgery. What ulcerative colitis patients like most about having any kind of pouch is that they no longer have the severe urgency or need to run to the bathroom.
After ileal pouch surgery, the patient must have an examination of the inside of the pouch with an instrument called an endoscope every year or every other year for the rest of his or her life to watch for the development of precancerous cells. In addition, all types of pouches can develop pouchitis, an irritation and inflammation of the inner lining of the pouch. Pouchitis is very common, but usually responds to oral antibiotics within 24 hours.
Overall, the long-term success rate of the pouch procedure is approximately 95%. However, there is a 5-10% chance of failure after pouch surgery. Most failures are due to the wrong diagnosis (for example, constructing a pouch in cases of Crohn’s disease), persistent severe pouchitis, or complications of surgery.
In some cases, the pouch may need to be repaired or removed and replaced with a new pouch. Another option is to convert the pouch to a permanent ileostomy (an opening through the abdominal wall to evacuate waste).
When is an ileal pouch not recommended?
People in the following situations or who have these conditions may not be good candidates for ileal pouch surgery:
- Crohn’s disease: This inflammatory condition of the entire digestive tract has a high risk of returning after treatment. Therefore, it is not a good idea to use the small intestine to construct a pouch. In some cases of pure Crohn’s colitis without small bowel or perianal disease, a pouch may be an option.
- Anal incontinence: problems controlling rectal functions.
- Older age: Although a number of elderly patients do well with an ileal pouch, the ideal age range for this surgery is 20-50 years old, when anal sphincter control is at its best.
- Obesity: People who are morbidly obese are not good candidates because of the greater chance of surgical complications, and a thick abdominal wall that makes the procedure more difficult to perform.