Q What Is Anal Fistula or Fistula-in-ano?
Anal Fistula is an abnormal passage (communication) between the interior of the anal canal or rectum and the skin surface around the anus.
Rarely, the fistula may communicate from anus (rectum) to Vagina (Recto-Vaginal Fistula), Urinary Bladder (Recto-Vesical Fistula), Urethera (Recto-Uretheral Fistula) or other pelvic structures, including the bowel.
A probe put in through external opening and coming out through internal opening
Q What is a Fistula? How is it different from a Sinus?
Fistula is a tract (passage) which communicates between two surfaces or body parts. Therefore it has two openings. Whereas, a Sinus starts from a surface and ends blindly without connecting to any other surface. Therefore, a sinus has only one opening.
In case of an Anal Fistula, the two body parts which the fistula tract connects are the anus (rectum) lining and the skin (around the anus or buttock) . In cases of Peri-anal Sinus, the opening in the skin doesn’t connect to the anus (rectum). However, Peri-anal Sinus cases are not common and most of the times, such cases are Anal Fistula cases with a very small anal opening.
Q Why is Anal Fistula such a dreaded (feared) disease? Is it really dangerous?
Anal Fistula is a dreaded disease. This is basically for three reasons
1. If the treatment is not done, the pus inside the fistula can spread further leading to formation of multiple tracts and several opening in the skin around the anus. This makes the fistula more complex and further difficult to treat.
2. Anal Fistula treatment is associated with high recurrence rate. A lot of patients who get themselves operated by routine surgeons have to undergo multiple operations to get cured. The lure of curing this disease without operation by quacks further complicate the treatment. Therefore, Anal Fistula should always be treated by an expert Colo-Rectal Surgeon who is proficient in dealing with Anal Fistulas.
3. Another important issue is that many surgeons are used to /comfortable doing a particular procedure for Fistula. They do the same procedure in all the patients. There are 5-6 procedures to treat Anal Fistulas and none of these procedures is perfect. Therefore, different procedure is indicated (should be done) in different patients, depending upon the type and complexity of that patient’s fistula. A single procedure cannot and should not be done in all the procedures. Very few surgeons are expert in doing all the procedures of Anal Fistulas.
4. There is a risk, though low, of cancer formation in the long standing Anal Fistulas. Therefore, Fistulas should always be treated at the earliest.
Q How is Anal Fistula caused?
Most fistulas begin as anorectal abscesses. When the abscess opens spontaneously into the anal canal (or has been opened surgically), a fistula may occur. Approximately, 8-50% of perianal abscess patients end up having an anal fistula.
Other causes of fistulas include tuberculosis, cancer, injury (trauma), Crohn’s disease, after Radiation therapy, anal Fissure, and infections (actinomycoses, chlamydial etc). Fistulas may occur singly or in multiples.
Q What is Ano-rectal abcess?
An anal abscess is an infected cavity filled with pus found near the anus (the opening of the anal canal) or rectum (the portion of large intestine just proximal to the anal canal). This can results from a blockage of the anal glands located just inside the anus. According to the crypto-glandular theory, abscesses often develop from cryptitis which may be associated with an enlarged papillae in the anal canal. They start as cellulitis-a diffuse inflammation, characterized by swelling and redness, which has not yet localized to form an abscess. Then the infecting organisms burrow into the anal glands, producing circumscribed areas of pus in the region of the anus and rectum.
An abscess produces pain and swelling near the anal opening. Fever may also be present. Treatment consists of surgically draining pus from the infected cavity and making an opening (incision) in the skin near the anus to relieve pressure. Sometimes a small catheter is left in the incision for several days to assure adequate drainage. In 8-50% of individuals, a fistula will form after the abscess has been drained.
Q What are the types of Anal Fistulas?
- Intersphincteric-Fistula tract passes between the two sphincters- 64%
- Trans-sphincteric- Fistula tract crosses the two sphincters- 30%
- Submusoal- Fistula tract passes between the sphincters and the mucosa of anus and rectum 5%
- Extrasphincteric- Fistula tract goes beyond the sphincter- 1%
For practical purposes, Anal Fistula are 2 types- Low & High. Low Fistula are present in the lower part and do not extend up to the ano-rectal sling [ muscle layer responsible for continence (control on passage of motions)]. High fistula extend up to or beyond ano-rectal sling. Knowing the type of fistula is important because high fistula if not managed properly can be associated with incontinence.[loss of control on passage of motions]
Q How is Anal Fistula diagnosed?
- Fistula probe
- Endo anal Ultrasound
- Magnetic resonance imaging
Q How is Anal Fistula treated?
An anal fistula usually lasts until it is surgically removed. The following methods are available to treat anal fistula:-
2. Endorectal/ Anal sliding flaps
4. Fibrin Glue
5. AFP – Anal Fistula Plug
6. LIFT (Ligation of Inter-sphicteric Fistula Tract)
7. VAAFT ( Video- Assisted Anal Fistula Treatment)
There is a direct relationship between incontinence and the amount of sphincter muscle divided. The goal of surgical treatment is thus two fold- to eradicate the suppurative( pus forming) process permanently without compromising anal continence
Fistulutomy/Fistulectomy has been the mainstay of treatment. In this surgery, the fistula tract is laid open by cutting out the whole tract with knife. This leads to a large wound from the anal opening to the buttock . Understandably this leaves the patient with lot of pain in the post operative period. The patient needs hospitalization for 4-8 days and requires dressings for this wound for 4-6 weeks .The patient obviously is off the work for few weeks. In spite of all these difficulties, this surgery is associated with a high recurrence rate. Other known methods such as seton treatment and fibrin glue method have also been not widely accepted due to requirements of repeated follow-up visits and high recurrence rates.
In high fistula(the fistulae going above the Rectal sling), the treatment is even more complex. It requires 3 operations in a staged manner. In the first stage, the anal opening is made in the abdomen wall called Diverting Colostomy (The fecal matter comes through an artificial intestinal opening created on abdomen wall with a pouch fitted over it). In the second operation, the fistula is operated upon by cutting it out in the same manner as described above. In the third operation, the Colostomy is closed. The whole procedure takes about few months time. In spite of all this, this operation had high recurrence rates and had the inherent risk of the most dreaded complication- Bowel Incontinence (Loss of control over bowel movements). So treating high fistula has been a nightmare for both surgeons and the suffering patients alike.
Now a new method, known as Anal Fistula Plug(AFP) has dramatically changed the way we can treat this complex disease. This treatment requires placement and fixing of the plug in anal fistula by a special technique. The plug is made of highly sophisticated absorbable material which provide the scaffold over which body’s collagen gets deposited and closes the fistula.
Comparative studies have shown this method to be very effective. The best aspect of this method is that it involves no cutting at all. So there is no post operative wound and any pain. Moreover the patient can go back to work the same day . In lots of patients, AFP plug can also be inserted under local anesthesia making it a wonderful Day-care procedure for treating anal fistula. Most important, this method can be used successfully to treat High Fistula. There is no need for any Colostomy. The risk of Bowel Incontinence is also not there at all.. Compared to the staged operations where patient needs multiple hospitalizations for weeks, in this method the patient hardly needs hospitalization for 24 hours and goes back to work the next day. Somebody has remarked ”For high Fistula, AFP method is a ‘boon sent directly from heaven”. Apart from all these benefits, the success rates of Anal Fistula Plug(AFP) have been higher than all other known procedures.
In LIFT procedure, the sphincter is not divided. A cut is given and a plane is developed between the two anal sphincters and the fistula tract passing between the two sphincter muscles is isolated. This portion of fistula tract between the sphincters is ligated (tied) and excised (cut out). The internal opening of the tract is cauterized and the portion of the fistula tract outside the sphincters is curretted, cleaned and left open so that it can drain freely and get healed.
In VAAFT, a fistulascope is inserted through the external opening and the whole tract is visualized on camera. The internal opening is localized through the endoscope while visualizing the ano-rectum from outside. After this, two stitches are taken through the internal opening so as to isolate the internal opening. After this, the fistula tract is cauterized with a monopolar cautery electrode so as to coagulate (burn) the fistula mucosa (lining) from internal opening to the external opening. The necrotic burnt tissue is taken out with the help of a brush and forceps. After this, the internal opening is lifted with the help of two stitches taken earlier and closed with a linear cutting Stapler which closes the tract at the level of the internal opening.