Treatment of Anal Fistulas
Surgery is almost always needed to treat an anal fistula effectively. The type of fistula surgery used generally depends on the locations of the opening and the amount of anal sphincter muscles that it involves.
Surgery for an anal fistula is usually carried out under general anaesthesia, and most procedures can be performed on an outpatient basis or with just a short hospital stay. In some instances where there is extensive infection or complicated tracts, patients may stay overnight after surgery.
Main treatment options for anal fistulas include:
The most straightforward type of fistula surgery is the lay open fistulotomy. This involves cutting a small part of the anal sphincter muscle to open up the entire tract, which will then heal from the inside out.
However, this would not be suitable on deeper fistulas as it may lead to bowel incontinence from cutting too much into the sphincter muscle.
This is probably the most common procedure for anal fistula as most fistulas do not involve much muscles.
A seton is a suture made of polypropylene (or some form of rubber) that is placed around the tract. This allows the pus in the fistula to come out along the seton. At the same time, the seton slowly cuts through the muscle below and allows the muscle above it to heal, thus slowly moving the tract downwards through the muscle. However, a second operation may be needed to cut through the rest of the muscles once it is safe enough to do so without risks of incontinence.
The seton technique is a very safe procedure without the risk of damaging the sphincter muscles. However, its major disadvantage is that it most often requires a second surgery. In inexperienced hands, it is also possible that the actual tract / internal opening is missed and a false tract is created instead.
Advancement Flap Procedure
This procedure involves cutting away the lining around the internal opening, then freeing up the inner lining of the anal canal nearby (the flap) and moving (advancing) it to cover the internal opening from the inside.
This used to be the only available treatment for complex fistulas that are not suitable for lay open fistulotomy. However, it is becoming less and less frequently used in view of various new techniques to treat complex fistulas.
The Ligation of Intersphincteric Fistula Tract (LIFT) procedure entails finding the fistula tract between the internal and external sphincter muscles, and then tying and cutting the fistula tract there. It was originally designed for long tracts that passes through both sphincters, though there are now some surgeons who use it as treatment for all fistulas, even for those where the tracts only pass through the internal layer.
This makes use of a special material to fill up the cavity of the tract. It is a relatively simple process where the fibrin is injected to fill up the cavity and the body tissues then grow and replace the fibrin and close up the tract. The sphincter muscles are not cut and hence there is minimal risk of causing damage to the muscles and incontinence.
However, the success rate of this procedure is lower than the others.
This uses a special plug made from pig’s tissue to fill up the tunnel. The body tissues then grow in and seal up the tract. It is similar in concept to the fibrin glue, except this one uses solid tissue to fill up the tunnel, while the fibrin glue injects a liquid which then solidify. Likewise, there is minimal risk of causing damage to the sphincters, but the success rate is relatively low.
Video-Assisted Anal Fistula Treatment (VAAFT)
This is one of the latest techniques available for the treatment of complex fistulas. It allows the surgeon to insert a video scope into the fistula to view the entire tract and trace it to its internal opening. The internal opening is then closed, and the tract is cleaned using a brush and probe through the video scope. One major benefit of this method is that it is minimally invasive even for complex fistulas, and will not require a long cut on the skin.
The key point to anal fistula surgery is to find the internal opening and ensure that it is closed. All of the abovementioned techniques are just different tools available for the colorectal surgeon to choose to use and treat the fistula.
Anal Fistula Surgery: Risks, Recovery & Recurrence
The main risk of anal fistula surgery is bowel incontinence caused by the excessive cutting of the anal sphincter muscles, which are responsible for opening and closing the anus. Other common risks include bleeding, infection and recurrence of the fistula.
Most fistula surgery can be done as a day procedure. In some cases, however, in the presence of underlying infection along the fistula, or for a complex fistula which involves cutting out more tissues, the patient will stay one or two days after the surgery.
Most people are able to carry on their normal daily activities after surgery, and have some degree of pain only during bowel movements.
It is important to plan for time after surgery to go back to the clinic for review and for cleaning the wound, if necessary.
The level of risk, duration of recovery and chances of recurrence are generally a combination of the complexity of the fistula and how meticulous the wound cleaning is after surgery. Speak to your colorectal surgeon for more information before embarking on the recommended treatment plan.