Colorectal - Anal Fistulas and Seton

Who we are

The Colorectal Nursing Team are a team of specialist nurses who are here to offer support, guidance, advice and teaching for patients with surgical lower gastrointestinal issues. We can provide clinic assessment, dressing support and advice and can aid you in the care of your wounds, setons and bowel function. Please contact us as below as and when required.

Contact us

Please contact the Colorectal Nursing Team for further advice/ support by the following methods:

Telephone: 0161 206 1249

Please leave a voice message if no answer, including your name, DOB or hospital number and reason for call, and we will get back to you as soon as possible.

Email: colorectalnursesSCO@nca.nhs.uk

Note our working days are Monday - Friday 9am - 4.30pm

Alternatively, you can contact your named consultant’s secretary.

What is an anal fistula?

A fistula-in-ano (anal fistula) is a track running from the skin on the outside of the buttock/anal area to the inside of your bottom. There are different types of fistulae from simple to complex branching ones. Some fistulae may run through the sphincter muscles (the ring of muscles that open and close the anus and are responsible for continence).

There are other types of fistulas including rectovaginal, colovesical, entero-enteric and enterocutaneous, but for the purpose of this leaflet we will focus on perianal fistulas.

Why do they occur?

Most commonly fistulas occur because of an abscess - a collection of pus under the skin next to the back passage. It can occur from blockage and infection of the glands inside your bottom.

It presents as a painful lump and can be associated with a fever (high temperature and shivering). The abscess can either burst itself or continue to grow but can become so painful that an operation is needed to drain it.

Fistulas can also occur in association with conditions that affect the bowel such as Crohn’s disease, diverticular disease, trauma (such as childbirth), cancer or radiation treatment for cancer, sexually transmitted infections or TB.

The fistula can lead to discharge of pus, blood or mucus from an opening in the skin. Once established an operation is often required to manage it.

Treatment for fistulas

There can be several stages to treatment depending on whether the muscles around the back passage (sphincters) are affected.
An MRI scan maybe carried out to assess the fistula prior to surgery.

The aim of surgery is to drain any infection whilst at the same time avoiding damage to the sphincter muscles. Damaging these muscles could lead to bowel incontinence (loss of control over your wind, fluid or solid motion). Clearly these can be difficult decisions to make, and your surgeon would always discuss the risks and benefits with you. Even after discussion some treatment decisions must be made whilst you are asleep during the operation.

Unfortunately, it is common for a fistula to come back despite surgery, and it is not unusual for some patients to have repeated operations.

Fistulotomy

This is the simplest way to treat a fistula which involves cutting open the length of the fistula track to ‘open it up.’ This offers the best chance of cure. This leaves a small raw area that will heal with time. Sometimes a small dressing is needed but often the wound just needs to be kept clean, and a small pad used to prevent any soiling. It is usually safe to cut a small amount of the anal sphincter muscle and initially you may notice a reduction in your ability to control your wind, this should resolve with time.

When a fistula runs deeply it cannot always be treated with a fistulotomy because it would involve cutting too much sphincter muscle and could result in incontinence.

What is a seton?

A seton is a special type of flexible material that is passed through the opening in the skin, along the fistula track, and back out through the anus where it is tied loosely to form a loop with a knot.

The seton allows the fistula to drain any fluid and prevent build up, prevent more abscesses from forming and improve overall healing. You will continue to have a slight discharge, but this should be far more manageable than the original fistula. This is the safest option, but it does not cure the fistula.

Generally, there are two types of setons:

• A loose seton – for drainage
• A cutting seton – gradually tightens, aiming to eventually make its way through the tract to open it up.

Setons can remain in place for weeks, months or years depending on the reason that the fistula developed and can also be replaced later if required.

Learning that a seton will be in place for a long period of time can be stressful. In many cases the length of time a seton may be required for is not always known. Sometimes there can be need for more than one seton if there are multiple fistulas present.

Initial support will be from community nurses and an assessment and teaching will be provided by the colorectal nursing team.
Once the initial wound has healed you should be able to manage this independently at home.

To remove the fistula for good sometimes requires several operations using setons and gradual laying open of the fistula tract or a different approach as below.

Seton Care

The main points of seton care are to keep it clean, allow it to drain, ensuring the seton is not stuck and for you as a patient to be comfortable.

Keeping the area clean will be an important part of the aftercare process. This can include daily showers or as warm as you can tolerate salt bath which help to increase blood flow to your skin and can also reduce pain, itching and irritation. Avoid using soap or perfumed products in the water until healed, but you can buy Epsom salt to use in your bath, which can help to clean and drain any build up. We also recommend that you undertake dressing or gauze tuck changes regularly, to keep the surrounding skin clean and dry and prevent skin irritation and infection.

It is recommended that you carry out daily flossing of your seton to prevent blockage, over healing around your seton and aid drainage. This should be done in a gentle slow movement. You should also feel the seton to ensure the knot of the seton is out of the tract. Please ask the nursing team if you require demonstration of this.

Although a seton can cause anxiety please note that when recovered from the surgery a seton should be comfortable and should not affect bathing, swimming, sexual activity or bowel function. It is possible to live a full life with a seton, but it may take some adjustment time to figure out practical aspects of living with a seton.

Symptoms to be aware of

• High temperature
• Night sweats
• Feeling unwell
• Pressure building up in the bottom (like sitting on a ball)
• Site of fistula becomes red, or hot to touch
• Change in discharge
• Increase in pain

If you develop any of these symptoms you can contact the colorectal nursing team within office hours, or your GP for further assessment. Out of hours we would encourage you to contact 111 or attend your local A+E for further assessment.

Other treatment options

LIFT technique

LIFT (ligation of inter sphincteric fistula tract) procedure is used for fistulae that cross the sphincter muscles. The space between the muscles is opened, the track divided, and the opening stitched closed. Initial studies suggest this can be very effective in up to 80% of patients. It is an attractive option as it does not involve cutting the sphincter muscles.

Fistula plug

This procedure involves a specially designed cone shaped plug. The plug is stitched into the track in a quick operation. The skin opening is not completely sealed so that the fistula can continue to drain. The plug acts as a scaffold for new tissue to grow in and close the fistula. It is a less invasive technique with less risk to continence but has a variable failure rate.

Fistula Paste

This technique involves inserting or injecting collagen paste into the fistula track to close the track, then an absorbable stitch is inserted at the internal opening to close the end. The external opening is partially closed to allow any inflammatory fluid to drain out without allowing the collagen paste to escape.

Further information

Please see links below for research regarding the above topics.

FIAT Trial – Anal fistula plug versus surgeon’s preference for surgery for trans-sphincteric anal fistula
https://www.journalslibrary.nihr.ac.uk/hta/HTA23210

Advances in the treatment of Anal fistula: A mini-review of recent Five – year clinical studies
https://www.frontiersin.org/journals/surgery/articles/10.3389/ fsurg.2 20.586891/full

The Multidisciplinary Management of Perianal Fistulas in Crohn’s Disease: A Systematic review
https://www.cureus.com/articles/101986-the-multidisciplinary- management-of-perianal-fistulas-in-crohns-disease-a-systematic- review#!/