Anal abscess and fistula

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Anal abscess and fistula is a frequent disease that causes inflammation and fluid discharge. Treatment of anal abscess- fistula is at times difficult and inflammation can sometimes reappear.


Fistula or abscess?

Perianal abscess is a collection of pus in vicinity with the anal canal. This acute condition is characterized by pain, and local inflammation, rarely with fever  while fistula is presented as the long-standing, relatively painless lesion with pus discharge. Flareups and remissions are quite common in perianal abscesses. Pus and inflammation should be treated as an emergency by surgical drainage of pus. Postoperatively, a skin opening with pus discharge is left. This is the clinical appearance of a perianal fistula.



Perianal inflammation is caused from an infection with an internal, anal opening. In case of hidradenitis (skin disease), there is no intra-anal opening. Hidradenitis is more frequent in obese and smokers. Rarely, anal fistulas are a manifestation of Crohn’s disease or after external blunt injury or foreign body ingestion. Other uncommon types of anal fistula are postoperative fistulas, fistulas after pouch surgery, low anterior resection, anovaginal or rectoprostatic fistulas.



The abscesses occur suddenly, within a few days, as a painful inflamed swelling, combined occasionally with fever. Fistulas appear as an opening with pus discharge. Skin openings may heal or reappear. In case, there are multiple skin openings and fistulas, hydradenitis maybe suspected. Rarely, fistulas can be early diagnosed only with the presence of a painful intra-anal bulge.


Diagnosis and preoperative diagnosis

An important feature in the diagnostic and therapeutical assessment of perianal fistulas is the exact location of internal opening in the anal canal. Other significant features of preoperative assessment are fistula’s position in correlation with the anal sphincters (circular muscles which hold the stools) and the proportion of sphincters’ muscle beneath the fistula tract. Manual examination by an experienced surgeon may provide significant information about orientation of fistula. For the diagnostic assestement of perianal conditions is frequently requested NMR scan (Nuclear magnetic resonance). However, in our practice, we use 3-D (3-Dimension) endoanal ultrasound for 25 years. Due to our long-term experience with 3-D ultrasound, we are able to obtain an immediate diagnosis, concerning perianal inflammation, and in addition detailed information about significant features of fistula tract and its relationship to anal sphincters. 3-D ultrasound gives us the ability to make measurements in millimeters. On the contrary, NMR usually gives indefinite answers to the above questions and even completely wrong information, in the worst of cases.


Treatment – Techniques (laser)

Abscesses containing pus should be treated by draining pus out of the abscess cavity. If the surgery is delayed, abscesses can get worse and the patient may have quite important pain. in rare occations, septicemia with hypotension may also occur. If abscesses are not eventually surgically drained, they are eventually drained by themselves.. Nevertheless, in this instance, the abscess has been expanded greatly and it may penetrate deeper into anal sphincters, making the final treatment more complicated. Due to the fact that abscesses usually originate from a intra-anal opening, postoperatively a fistula often remains with pus discharge after the abscess drainage. This condition should be treated in a second phase. Furthermore, there is the opinion that poor drainage of abscess causes the fistula is totally wrong. In selected cases, a complete treatment of anal fistula-abscess can be achieved in one surgical procedure by a proctologist-surgeon and after a detailed 3-D ultrasound.

Antibiotics should be given as a unique treatment of perianal abscess only when an untrained surgeon cannot detect the abscess, especially if there is no preoperative diagnostic assessment. Antibiotics often manage to limit inflammation, and the later often recurs to a greater extent. There are more than ten available techniques for fistula treatment. The existence and use of such a large number of surgical procedures indicate that none of these are appropriate for all types of fistulas. The main aim of the treatment is at first not to damage anal sphincters, and to treat definitely the fistula by causing the smallest possible wound and the less possible postoperative disablement. In recent years, a great number of procedures and appliances have been proposed for the treatment of fistulas. In their introduction they have been advertised as a final solution with important financial and advertising benefits to the medical providers, even though by passing the time all their disadvantages came to surface.

The oldest and simplest technique is to lay open of the fistula tract. The use of a seton (loose or cutting) suture for more difficult fistulas has been used since Hippocratic era. In recent years, many new techniques have been proposed (LIFT, Flap, AFP, Permacol, VAAFT, OTSC, etc.). Some appear and disappear as comets after their disadvantages emerge. Filac-Laser technique in certain cases is a method that promises a lot because it does not cause any injury and does not injure sphincters. Its success rate, according to the inventor of the method, is about 60-70%.

Any proctologist surgeon operating fistulas should not limit his armamentarium only in single technique but should also seek to apply the appropriate procedure in each patient. For a particular fistula surgery, we may use a combination of two or more techniques at the same time in order to gain the best result possible. Some fistulas can be cured within half an hour, if they are easy to treat. More difficult fistulas require patience and more than one surgical procedures for a complete cure. The most important aim for a patient with a fistula is the correct selection of the proctologist-surgeon. If a bilateral trusted relationship between patient and surgeon has been established, a definitive treatment is very likely. In difficult cases the patient must have a lot of patience.


Postoperative course

After a laser surgery, wherever it can be applied, there is no trauma and the patient can return to his activities in a couple of days. In the other techniques, surgical wound with discharge can be present. This usually requires proper wound care and frequent dressings changes.


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