Perianal fistula: symptoms, causes, diagnosis and treatment

• Perianal fistula is a communication between the anal canal and the perineal skin at the exit of the anus.
• Perianal fistula requires surgical treatment to eliminate it definitively: fistulotomy or fistulectomy.
• The duration of recovery after a perianal fistula will depend directly on the patient's situation and the surgical technique used.

Before explaining what a perianal fistula is, it is important to clarify what a fistula is. It is an abnormal connection that occurs between two parts of the body. Thus, it can develop between two organs, between the intestine and another structure, between two blood vessels, etc.

A perianal fistula is a connection between an external opening, on the skin of the anus, and an internal opening, inside the anus or rectum.

The anal fistula is a tube-shaped conduit under the skin surrounding the anus. The external and internal orifices referred to above communicate with each other. 

This communication is called a fistulous tract and has its origin in glands inside the anal canal whose function is to lubricate it to allow the faeces to pass smoothly.

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This fistulous tract passes through the anal muscles or sphincters (anal sphincters are involuntary muscles that allow people to control the opening and closing of the anus) to an external hole in the skin, usually in the skin near the anus as mentioned above, and pus or even faecal matter is discharged through it.

The incidence of perianal fistula is more common in men than in women and usually occurs between the ages of 30 and 50.

The disease usually occurs in adults, although it is also common in children with associated inflammatory bowel diseases such as Crohn's disease.

Symptoms may be absent if the fistula is located in an area away from the anus, or they may be severe and intense pain. Read all about the symptoms of perianal fistula below.

The symptoms of a perianal fistula are pain in the perianal area and discharge of pus or foul-smelling drainage. The patient who comes to the doctor's office often presents with the typical symptoms of perianal fistula over a long period of time but has not visited the doctor before because of embarrassment or because the symptoms occur intermittently.

The intensity of the pain caused by perianal fistula may be accentuated by defecation, sitting, coughing or sneezing, etc.

A perianal fistula may have no symptoms and therefore go undetected, especially if it is located on the inside of the anus. Also, when the patient presents with symptoms, it is most likely to be as follows:

• Pain in the area where the fistulous tract is located during defecation.
• Anal irritation, where the exit of the perianal fistula is located.
• Continuous or intermittent discharge, often staining the patient's underwear.
• Itching and stinging in the area of the anus where the fistula is located.
• In the event of infection, fever may appear.

A perianal fistula can develop due to injury during surgery, infection or inflammation in the area, however, the most common cause is a blocked gland.

The glands responsible for lubricating the anal canal can become blocked due to excess mucus in the area, leading to the accumulation of germs in the anal canal, infection and subsequent formation of an anal abscess with pus.

Infection caused by mucous build-up is the most common cause of perianal fistula in 80-90 % of cases.

These abscesses may drain spontaneously or be treated surgically for emptying and cleansing. Detection and drainage of these abscesses could prevent up to half of all cases of anal fistula. 

In either case, the fistulous tract formed by the abscess may continue to grow until, as mentioned above, it crosses the muscle or sphincters and reaches the exterior or another exit point such as the vagina.

While most fistulas are the result of an anal abscess, which we call primary fistulas and which represent 90% of all perianal fistulas, there are others (about 10%) that are caused by other processes such as Crohn's disease, sexually transmitted diseases, anal sex, trauma, tuberculosis, cancer, diabetes, a weakened immune system, haematological diseases or diverticula.

Crohn's disease and ulcerative colitis are risk factors predisposing to the development of perianal fistula.

As you have read in the first paragraph, Crohn's disease is an inflammatory bowel disease that can affect other areas such as the mouth or anus.

In addition to this, there are other health circumstances and situations that can favour the appearance of perianal fistula:

• Diabetes
• Infections
• Anal sex or some trauma to the area
• Anorectal cancer
• A weakened immune system
• Radiation therapy. The consequence of radiation for prostate, pelvic or rectal tumours, i.e. radiation of the perianal tissues.

To make the diagnosis of perianal fistula, the physician will look for abscesses and openings in the skin by physical examination. The anal area will be reddened and painful to the touch. Thus, when located, the path and depth of the fistula will be defined with a probe.

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However, fistulas are not always visible as sometimes the lesion is not on the surface of the skin. In these cases, a digital rectal examination or observation of the anal canal with the help of an anoscope is necessary. The anoscope is a short, rigid tube with a light attached to the end, with which the cavity can be observed and samples can be taken.

In addition to this diagnostic test, the specialist may sometimes request an ultrasound scan of the anal canal area to determine the fistulous tract.

During the diagnosis of perianal fistula, the source from which the abscess has developed should be sought.

If, after the diagnostic tests mentioned above, the doctor finds and determines that the problem for which the patient has come to the consultation is a perianal fistula, a series of tests will be carried out to determine whether the appearance of the perianal fistula is related to other types of diseases such as the aforementioned Crohn's disease. These tests may be a complete blood test or a colonoscopy.

To prevent perianal fistulas, good hygiene must be carried out in the area. But, when they have already appeared, the only solution is surgery.

After a complete study of the fistula and the fistulous tract, the treatment to be carried out to resolve the perianal fistula will be determined.

As you have seen, there is no viable non-surgical treatment for the treatment of a perianal fistula. Symptoms can be relieved with some medications but, when a fistula occurs in the anus, the only definitive option is surgery. 

Before any surgical action is taken, it is necessary to make sure that there is no infection or else the patient will have to undergo antibiotic treatment prior to surgery.

Perianal fistulas that pass through the sphincter are the most delicate, as a poorly performed incision in this area could cause significant damage to the sphincter and lead to permanent faecal incontinence.

Different surgical techniques can be used to perform the operation for perianal fistula, the use of which will be determined by the characteristics of the patient, the severity of the problem and the doctor's criteria. 

It is also possible that during the anal fistula operation, the surgeon may change the technique or make modifications to it due to new developments encountered during surgery, always with the sole intention of improving patient safety and providing the most appropriate treatment. 

The following is a brief explanation of the different operations for the treatment of perianal fistula:

Fistulotomy

This procedure is performed under regional anaesthesia in the vast majority of cases. During surgery, the specialist will assess the depth and extent of the fistulous tract to determine the technique to be followed during the surgery.

Fistulotomy is performed when perianal fistulas are simple.

In the case of fistulotomy, the specialist in coloproctology and general surgery will cut the skin and part of the sphincter muscle to flatten the fistulous tract so that it can heal from the inside to the outside.

The aim of fistulotomy is to open and empty the fistulous tract, while ensuring rapid and efficient healing.

Absorbable materials that enhance healing may be used in this procedure.

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Fistulectomy

The anaesthesia used in fistulectomy for the treatment of perianal fistulas is regional in most cases and is used for cases where the fistula is more complex.

Fistulectomy involves total resection of the fistulous tract.

During the surgery, although rarely and always in very complex cases, it may be necessary to repair the sphincters, place grafts in the area and even use an artificial anus in extreme cases.

The function of fistulectomy is the same as fistulotomy, with the difference that the wound will be larger and healing will be slower.

The approximate duration in both cases is between 30 - 90 minutes, depending on the characteristics and severity of the perianal fistula.

At the end of the perianal fistula surgery, the patient will be taken to the recovery room to finish recovering from the anaesthesia and will be advised and explained how to carry out the post-operative dressings and sitz baths.

The most frequently asked question about perianal fistula surgery has to do with the postoperative or recovery stage and is about bowel movements after surgery.

It is normal to have some pain and bleeding with bowel movements during the first week. However, you will be able to make use of fibre foods and stool softeners to make it less uncomfortable. However, the doctor will tell you all this during your consultation before you are discharged from the hospital.

The recovery or postoperative period for a perianal fistula will depend on the technique used and the severity of the fistula corrected. If a fistulotomy has been performed, recovery will take approximately one week to be able to lead a normal life, while the wound will heal after 4 weeks.

On the other hand, if a perianal fistula surgery has been carried out by fistulectomy, recovery takes a little longer because the surgical wound is larger. The patient will have to wait around two weeks before being able to lead a completely normal life, with the wound healing after around 6 weeks.

It is important to bear in mind a series of indications so that your recovery is as quick and effective as possible. For this reason, the doctor will inform you about the things you can do to take care of yourself once you are discharged:

• Get enough rest.
• Walk daily.
• Eat a normal diet, unless there is an upset stomach. In this case, introduce soft, low-fat foods.
• Drink plenty of fluids (this may be contraindicated by the doctor).
• Take the medicines prescribed by the doctor, up to the prescribed period.
• Take care of wounds as prescribed by the doctor.

In addition to informing you about this, the specialist will point out the signs for which you should see a doctor as a matter of urgency. These include the following:

• Pain or redness in the leg or groyne.
• Pus coming out of the incision
• Fever
• Discomfort that does not go away with medication.

Operarme offers you an immediate and free surgical assessment consultation so that you can tell the specialist about your case. In this way, he or she will prepare a surgical diagnosis in which you will be informed of the most appropriate technique for your situation.

In addition, for the assessment to be much more accurate, it is important that you provide all the medical tests you have undergone, as well as your medical history.

However, Operarme has a Patient Service Team available to answer your questions and provide you with all the information you need about the anal fistula operation.

To book a consultation with the specialist you can fill in our contact form or call at +34 91 141 33 56.

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