Seton insertion & management

A seton (a thin, soft loop of thread or flexible tubing) is passed gently through the fistula tract — the tunnel that has formed — and tied loosely so that it sits in place without cutting. Think of it like a drain that keeps the tunnel open in a controlled way: it lets any infection drain away, prevents abscesses from building up, and allows the tissue around the sphincter muscle (the muscle ring that controls your bowel) to settle and strengthen over time. A loose seton is used as a long-term drain for high or complex fistulas where removing the fistula immediately would put your bowel control at risk. For fistulas related to Crohn's disease, a long-term seton is often a reasonable ongoing strategy, kept in place while medical therapy controls the underlying inflammation.

• A high transsphincteric fistula — one that passes through a significant portion (more than 30%) of the external sphincter muscle, making it too risky to lay open in one go
• A complex or horseshoe fistula — one that branches or curves around both sides of the anal canal rather than running in a simple straight line
• A fistula associated with Crohn's disease, where inflammation makes the tissue fragile and definitive repair is rarely appropriate
• A fistula in someone whose sphincter muscle has already been weakened or injured — protecting what remains of your muscle control is the priority
• As the first step in a staged plan — the seton settles the infection and softens the surrounding tissue before a more definitive, muscle-preserving repair is attempted
• A fistula with an active infection (sepsis) that needs to drain and calm down before any further surgery is safe

• Your sphincter muscle is completely left alone — there is no cutting of muscle during seton insertion, so your bowel control is protected throughout this stage of treatment
• Infection is kept drained and under control, preventing painful abscesses from forming while the next step of your treatment is planned
• Most patients live normally with a seton in place — you can return to work, exercise, and daily life within a week
• The time the seton spends in place allows inflammation to die down, making any later muscle-sparing repair more likely to succeed
• For Crohn's-related fistulas where a cure is not achievable, a long-term seton provides lasting comfort and drainage — a practical, dignified solution
• A day procedure — you go home the same day; no overnight hospital stay is needed

• The seton manages but does not cure your fistula: This is intentional — the seton is not meant to fix the fistula on its own. It is a bridge, keeping you comfortable and infection-free while the definitive plan is prepared. A cure will be attempted at a later stage when conditions are right.
• Some discomfort and mucus discharge: It is common to notice a small amount of mucous (clear or slightly cloudy fluid) around the seton. This is the drainage doing its job. Most people find it manageable with a small pad in their underwear.
• Seton migration or breakage: Occasionally the thread shifts or frays. If this happens, it can be replaced under a brief anaesthetic — it is a minor procedure.
• Cutting setons — important to understand: There is a type of seton that is gradually tightened over time to slowly cut through the muscle. This technique is not routinely used here. The loose drain seton used in this practice does not cut through muscle, so your bowel control is not at risk from the seton itself.
• Skin irritation: The skin around where the seton exits can become a little sore or red. A simple barrier cream keeps this comfortable.
• Infection around the tract: Occasionally a small abscess can develop alongside the seton despite it being in place. This is uncommon and treatable.

If you take blood thinners, diabetes medication, GLP-1 weight-loss injectables, or iron supplements, please flag this when you book — these need specific adjustments before the procedure. Full details are in the guide above.

• An MRI scan of your pelvis — a detailed imaging study to map the full course of your fistula, including any hidden branches, before the seton is placed
• No bowel preparation needed — no laxatives or enema required before this procedure
• A consent conversation at which the staged management plan is explained in plain language, so you understand what this step means and what comes next

• You will be admitted to the day-surgery unit at Warringal Private Hospital or Epworth Eastern on the morning of your procedure and given a general anaesthetic — you will be completely asleep and will not feel anything
• A thin probe is gently passed through the fistula to confirm its path, then the soft seton loop is threaded through and tied loosely — snug enough to stay in place, but not tight enough to cut
• If your fistula curves around both sides (a horseshoe fistula), small additional openings may be made to ensure all branches drain properly
• Local anaesthetic is injected to keep you comfortable when you wake up; you recover in the day-stay unit for a couple of hours
• Before you go home, you will receive written instructions explaining exactly how to care for and clean the seton — it is straightforward, and the nurses will go through it with you

• Days 1–2: Mild soreness around the seton and a little mucus discharge are completely normal — this is the drain working as intended. Take your pain relief regularly.
• Days 3–7: Most people are back to their usual routine within a week. The seton will simply become part of your everyday life.
• Ongoing seton care: Once a day — most easily in the shower — gently rinse around the seton with clean water or saline. This keeps the tract clean and prevents soreness. It takes about a minute and becomes second nature very quickly.
• Regular review: You will be seen regularly so the tissue can be checked as it settles. Whether the next step is a muscle-sparing repair, or whether continuing with the seton long-term is the right choice for you, will be discussed at these reviews.
• Planning the next step: Once inflammation has fully settled — usually several months after seton insertion — a definitive sphincter-preserving operation such as a mucosal advancement flap or LIFT procedure can be considered. Nothing will be rushed; the timing will be chosen together.
• For Crohn's patients: Surgical and medical care are closely coordinated with your gastroenterologist. Keeping your Crohn's disease well controlled with medication gives any surgical treatment the best chance of success.
• A post-operative review is routinely arranged 2–6 weeks after your operation, with timing depending on the type of surgery — this review is provided at no charge.
• For day-by-day instructions on seton hygiene, what to expect from the drainage, and what to watch for, see the Seton care aftercare guide on the Resources page.

Post-operative concerns: Please call our rooms on (03) 9816 3951 and leave a message — this will be sent directly as a text to Mr Nguyen. Alternatively, you may text the office mobile on 0499 090 126. We aim to respond promptly during business hours.

Emergencies: For any life-threatening emergency, call 000 immediately or go to your nearest emergency department. Do not wait for a call back from our rooms. For the Austin Hospital Emergency Department: (03) 9496 5000.