Ileoanal pouches – an update
Miss Sue Clark MD FRCS (Gen Surgeon)
Many of you with will have heard of or even had an ileoanal pouch, an operation pioneered by Professor John Nicholls at St Mark’s. I am honoured to have taken over his post on 1st March 2006 on his retirement.
I am not new to St Mark’s, having started my two years of research at City Road, and moved with the hospital to Northwick Park in 1995. I came back for my final year of specialist training in 2002, and spent some time at Mount Sinai Hospital in Toronto, the main pouch centre in Canada, before starting my previous consultant job at the Royal London in 2003.
Since the first operations in the late 1970s, over 1500 pouches have been constructed at St Mark’s, one of the biggest series in the world. Careful follow-up of this large group of patients has given us valuable experience of the problems that can arise, as well as accurate information about what pouch patients can expect in the long term. I hope that this article will provide an update on the subject.
What is an ileoanal pouch?
A pouch is made from small bowel to create a reservoir. This can be used to hold urine, or be situated inside a continent ileostomy (Kock pouch), in which case it is emptied several times a day by passing a catheter through the specially designed ileostomy into the pouch. These are both uncommon types of pouch, so I will not mention them any further. Most pouches are joined on to the anus, so that the faeces is held in the pouch and then evacuated via the anus in the usual way.
How is a pouch made?
Basically pouches are made by opening lengths of small bowel to produce ‘strips’, and then joining these ‘strips’ together to form a bag (Fig 1). In the early days a number of different designs of pouch were tried, all made from different numbers of ‘strips’ joined together in different ways (Fig 2). The commonest of these were S, W and J pouches. Almost all pouches made nowadays are J pouches. W pouches are a little bit bigger, so may hold more faeces, requiring less frequent visits to the toilet, but sometimes they do not empty efficiently, and more bowel is needed to make them.
The ‘strips’ of bowel used to make the pouch were originally sewn together by hand, but usually special staplers are used now. The staples are made of a titanium alloy, so they do not rust, and do not set off airport metal detectors or cause problems with MRI scanners! They can be seen on X-rays though.
The pouch can be joined to the anus (anastomosis) either by hand stitching or using a special circular stapler. Hand stitching is difficult, and the anus is stretched and can be damaged when it is done. Stapling is more straightforward, but sometimes it is necessary to make the join very low down in the anus, where it has to be hand-sewn.
Usually after a pouch has been made a temporary loop ileostomy is formed upstream of it to allow all the various joins to heal before the pouch is used. Usually the pouch is tested to check for leaks after 6-12 weeks, before the ileostomy is closed. This is done using a pouchogram: the pouch is filled with X-ray dye passed in through a catheter placed into the pouch through the anus, then several X-rays are taken over a few minutes.
Who needs a pouch?
Before the pouch operation, patients who needed to have their entire large bowel (colon and rectum) removed were inevitably left with a permanent end ileostomy. The introduction of the pouch allowed the small bowel to be joined to the anus with acceptable functional results. Virtually all patients with pouches have one of two conditions:
- ulcerative colitis (UC)
- familial adenomatous polyposis (FAP)
No patient ‘has’ to have a pouch for medical reasons. The ‘treatment’ part of the surgery is the removal of diseased bowel. The creation of a pouch is a way to join the bowel up again and avoid a permanent ileostomy. Some people who have the colon and rectum removed (proctocolectomy) prefer to have an ileostomy, and not run the risk of poor function or future complications associated with pouch surgery.
This is an inflammation of the bowel. The underlying cause is not understood. Increasingly it can be successfully treated with drugs, but in about a quarter of patients surgery is necessary. In most cases this involves removing the entire colon and rectum. If surgery is done as an emergency the colon is removed, but the rectum is left inside, because removing it in a very sick patient can be dangerous. It is better to wait until the person is better, then go back a few months later, remove the rectum and create a pouch. In people who are less unwell, it is possible to remove all of the large bowel and form a pouch at a single operation.
There is another inflammatory bowel disease called Crohn’s disease, which can behave very like UC in some patients. Pouches frequently develop serious complications in Crohn’s disease, so we are always very careful to make as sure as is possible that we are dealing with UC rather than Crohn’s by checking biopsy results and the pathology of the colon if that was removed at an emergency operation. Even then it can sometimes be very difficult to be certain that the diagnosis is not Crohn’s disease.
Familial adenomatous polyposis
This is an inherited condition in which people develop many hundreds of pre-cancerous polyps in the bowel when they are teenagers. These then turn into cancer in the thirties and forties. The only way of preventing this process is to remove the affected large bowel. In some people with FAP (but not all) this means removing the colon and rectum. The only way to avoid a permanent ileostomy is to have a pouch.
What can go wrong?
Any operation carries risks, such as thrombosis (clots) in the veins of the legs, chest infections or wound infections, etc. In the longer term anyone who has had extensive abdominal surgery will have adhesions (scarring which sticks loops of bowel together), which can cause episodes of obstruction (blockage). In most cases this settles down of its own accord, but sometimes surgery is needed to unkink the bowel.
The pelvic surgery required to remove the rectum can be difficult and involves operating close to the ureters (tubes which drain urine from the kidneys into the bladder) and the nerves which allow erection and ejaculation in men. The risk of damaging these is small (1-5% risk of impotence) and is really a risk of removing the rectum, rather than of pouch surgery itself.
The most serious problem is leakage from one of the seams (usually between the pouch and the anus). An ileostomy protects from the worst effects of leakage, but an abscess can form outside the pouch. Sometimes this can be successfully drained and the hole in the seam can heal. This does not always happen though, and chronic inflammation can result in a scarred pouch which will never work well.
Sometimes the join between the pouch and the anus narrows down (a stricture or stenosis) so that the pouch cannot empty properly. This may require stretching under anaesthetic, and then regular use of dilators to keep the anastomosis open.
About 30% of people with pouches for UC develop inflammation of the pouch (pouchitis) at some time. We do not understand why this happens, but in most cases it can be easily treated with a course of antibiotics and does not return. A few people have troublesome recurrent pouchitis.
Pouches made for FAP can develop polyps, so we follow this group of patients up very carefully and remove any large or worrying polyps.
Research done over the last five years has shown that women who have had pouch surgery may have difficulty getting pregnant. This is likely to be due to adhesions forming around the Fallopian tubes, and is actually probably a result of removal of the rectum rather than pouch formation. We are now trying to avoid the pouch procedure in young women, postponing it until they have completed their families if at all possible. If a woman with a pouch is having trouble getting pregnant we suggest IVF treatment.
On average someone with an ileoanal pouch will need to go to the toilet five times per day and once at night. There may be some mucus leakage.
As this is an average, some people will empty their pouches less often than this, and others will go more frequently. Codeine or Loperimide can help to slow things down. Over many years function seems to improve a little.
Some people have more difficult problems with continence, due to a combination of anal muscle weakness or damage, the loose faeces which are normal with a pouch and advancing age. Just occasionally an ileostomy is needed in these cases.
Overall about 90% of pouches are a success, and 10% fail, usually because of leakage and infection or severe pouchitis. In some cases a new pouch can be made, but the failure rate of ‘redo’ pouches is considerably higher than those done for the first time.
What have we learnt?
So what has changed in the thirty or so years since pouches were first performed?
Virtually all pouches formed now are stapled J pouches, with either stapled or hand-sewn pouch-anal anastomosis.
We can give people a good idea of what to expect in the short, medium and long term, and have developed ways of diagnosing and treating most pouch-related complications.
Recent work has shown that pouch surgery has a major effect on fertility, so we can now warm women about this, and try to avoid this type of surgery in young women who may wish to have a family.
Careful follow-up of patients with FAP has shown that they can develop polyps in their pouches, and need very careful follow-up.
The team at St Mark’s has developed a database which includes details of all pouches formed at the hospital. This is crucial in monitoring long-term results. We also have research groups looking at the following areas:
- fertility in women, to try to understand why this surgery effects fertility, and what the results of fertility treatments are in women who have had pouch surgery.
- the cause and treatment of recurrent pouchitis
- polyp formation in pouches in FAP – why polyps develop in the pouches and how to prevent them
We are enormously grateful to the patients who take part in these studies, as without them we cannot improve the surgery and other treatments which we offer.
In terms of technical progress, one of the most experience laparoscopic (key-hole) surgeons in the country, Robin Kennedy, has recently moved to St Mark’s. He is developing the ‘key-hole pouch’ operation. Several small cuts are needed to inert the key-hole instruments, and an incision is still needed to remove the diseased bowel, but this is far smaller than the wound needed for traditional surgery. This approach will not be suitable for all patients, but may benefit many in the near future.