Anal fistulae: diagnosis
The diagnosis of perianal fistula occurs during the rectal examination. The fistula is identified by means of a rectal exploration and of palpation of the tissues around the anus. To identify any secondary lesions, the specialist may also use transanal ultrasound.
After the physical examination, the specialist will recommend the most appropriate therapy.
Anal fistula and abscess
The therapy for resolving an anal fistula is surgery. The operation is performed with different techniques and procedures depending on the type of fistula.
If the fistula is associated with an anal abscess, the operation must be combined with the treatment of the perianal abscess. Anal fistulae represent the chronic phase of the anal abscess. Anal fistulae and anal abscess are in fact considered two stages of the same disease.
Perianal abscess: treatments
The perianal abscess can be removed in outpatient or surgically.
When the abscess is superficial, the surgeon can remove it in outpatient with local anaesthesia. Whilst draining the perianal abscess, the surgeon cuts the skin over the abscess and drains the pus inside it.
Conversely, if the abscess is deep, deep sedation surgery is required. During the operation the surgeon will aspirate the pus and evaluate whether to also treat the anal fistula.
However, surgery is always necessary in order to resolve an anal fistula.
The techniques depend on the features of the fistula and on the symptoms and they are not without risks. Let's look at them in detail:
The surgeon cuts the fistula along its entire length so as to favour the formation of a flat scar from the inside towards the outside. This surgical procedure is mainly used for smaller and more superficial fistulae.
The anal fistula is completely removed. The surgeon reconstructs the incision which forms in the sphincters using a flap of the rectum mucosa and sub-mucosa. In this way, damage to the anal sphincter is limited and therefore so is the risk of incontinence.
For deeper and more extensive anal fistulae, multi-stage surgery is used. The operation occurs in multiple stages in order to avoid damaging the anal sphincter.
During this procedure, the surgeon inserts a small tube, called a seton, inside the fistula. The seton allows to dissect and drain the contents of the fistula towards the outside.
Each time he sees the patient, the surgeon repositions and tightens the seton to progressively complete the treatment. In fact, the surgeon leaves time for the sectioned portion of the sphincter to heal between sessions. The treatment generally lasts a few months during which it is possible to carry out normal daily activities.
- Closure with fibrin glue, collagen or plugs
The surgeon injects a substance called fibrin glue into the anal fistula to help it close. Fibrin glue is obtained from coagulant substances contained in the human serum. Alternatively, the surgeon can inject collagen or implant small cylinders of biocompatible material called plugs. This technique is simple and minimally invasive, but has a high recurrence rate.
- Minimally invasive techniques: LIFT and VAAFT
In recent years new minimally invasive surgical techniques have been developed. These techniques make it possible to reduce hospital stays and surgery complications:
- LIFT technique | Ligation of intersphincteric fistula tract
A particularly complex surgical procedure. The LIFT technique involves opening the intersphincteric space, ligation and sectioning the fistula. At the end of the operation, the incision is closed with stitches. This technique allows to safeguard the integrity of the internal and external anal sphincter.
- VAAFT | Video Assisted Anal Fistula Treatment
A multi-step surgical technique useful for treating more complex anal fistulae. The VAAFT technique allows to view all the operating phases through a monitor and to reduce the risk of sphincter damage. The procedure is divided into two phases:
- diagnostic phase: identification of the route and of the internal fistula opening
- operational phase: destruction of the fistula from the inside, removal of the necrotic material and closure of the internal orifice.