Definition
By "fistula" we mean an anomalous canalicolo, of a purely pathological nature, which can put two internal organs or an internal cavity in contact with the skin (external). In general, fistulas are the final result of a severe inflammation, in turn caused by an abscess (complicated and pus-rich infection) which, bursting, gives rise to a tubular connection path.
Causes
Most often, fistulas are the final outcome of a severe trauma or infection that progresses to ASCess. The inflammation resulting from the lesion gradually involves the neighboring anatomical structures, thus giving rise to adhesions between tissues. Being a purulent infection - that is rich in pus (creamy fluid composed of bacteria, cellular debris, plasma and white blood cells) - the abscess tends to burst to pour its own content outside: in doing so, it creates a passage (called precisely fistula) which acts as a link between the center of the infection and the neighboring tissues.
Among the main causes of fistulas related to inflammatory phenomena we cannot forget Crohn's disease, often responsible for anorectal fistulas (which connect the rectum or another anorectal site with the skin) and enterocutaneous (between the intestine and the skin).
But inflammations are not the only causal factors of fistulas: these abnormal pathological pathways can in fact be induced by a malformed SURGICAL INTERVENTION.
Examples
- An incorrectly performed gallbladder operation may favor the development of biliary fistulas (which for example connect the bile ducts to the skin);
- A malformed tracheotomy can cause tracheoesophageal fistulas (between the esophagus and trachea).
Other types of TRAUMI can instead generate fistulas of other nature, such as the rectovaginal or vesico-genital ones. These variants of fistulas have been observed in numerous women who have suffered rape.
Furthermore, a particularly complicated and long TRAVEL can cause obstetric fistulas (pathological connection between vagina and bladder / urethra / rectum, see image to the side): it is an extremely dangerous delivery complication both for the unborn child and for the mother. In fact, based on the location in which the obstetric fistula originates, the woman undergoes severe and continuous urinary and / or fecal incontinence. The unborn child dies in most cases.
Obstetric fistulas originate due to an extremely difficult and prolonged labor in which the baby's head remains in the vagina for such a long time as to induce necrosis (death) of adjacent tissues (as marked by the blue stroke and surrounded in red). Due to the necrosis, there is the loss of the correct separation of the surrounding anatomical structures, with the onset of an abnormal communication between the genital and urinary tract or, more rarely, between the genital tract and the intestinal tract.
Types of fistulas
There are innumerable types of fistulas, classified essentially according to the area in which they arise, their position, their structure and the causative agent.
Given the numerous variants, to facilitate comprehension and facilitate memorization, the table lists the classification criteria for fistulas.
| Classification of Fistulas according to the structure | Classification of Fistulas based on position | Classification of Fistulas based on the cause |
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We also remember that fistulas can manifest themselves in acute form or, in more serious cases, become chronic: in the latter case, the fistula persists because it is continuously fed by pathogens involved in the infection (which produce exaggerated amounts of pus). In other cases, especially in urogenital fistulas, the connecting canaliculus may become chronic because biological fluids (eg urine, faeces) continue to pass into the affected tissue / organ.
Common fistulas and localization
Fistulas may appear hypothetically in every area of the human body, involving almost all internal structures. However, by examining medical statistics, we can identify the fistulas that most frequently affect humans:
- Fistulas of the circulatory system (eg pulmonary arteriovenous fistula, in which the canaliculus connects an artery and a vein in the blood)
- Fistulas of the digestive tract (eg fistulas of the stomach and duodenum)
- Fistulas of the urogenital tract (eg urethral fistula, rectovaginal fistulas)
- Fistula of the respiratory system (eg tracheoesophageal fistula)
- Fistula of the eyes and appendages (eg lacrimal fistula, mastoid fistula, periauricular fistula)
- Dental fistula (pathological canaliculus that connects the center of inflammation / dental infection with a neighboring tissue such as the mucosa, skin or alveolus
Therapeutic fistulas
