Anal fistulae: diagnosis
The diagnosis of perianal fistula occurs during a 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 clinician may also use transanal ultrasound.
After the physical examination, the specialist will recommend the most appropriate treatment pathway.
Anal fistula and abscess
The therapy for resolving an anal fistula is surgery. The surgical techniques and procedures depend 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: therapies
The perianal abscess can be removed in a day case hospital setting or surgically.
When the abscess is superficial, the surgeon can remove it in a day case hospital 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, sedation would be required before surgery is carried out. 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 fully resolve an anal fistula.
The techniques depend on the features of the fistula and on the patients symptoms and they are not without risks. Let's look at them in detail:
The surgeon cuts the fistula along its entire length to create a flat scar from the inside towards the outside. This surgical procedure is mainly used for smaller and more superficial fistulas.
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.
Seton For deeper and more extensive anal fistulas, 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 dissection and draining of the contents of the fistula towards the outside.
At each visit, 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 visits. 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 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 surgical 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 fistulas. The VAAFT technique allows the surgeon to view all the operating phases through a monitor helping 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.