Fistulas

Fistulas are pathological passages lined with granulation tissue or epithelium, connecting a pathological focus in tissues, organs or cavities with the external environment or with each other.

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What causes fistulas?

The occurrence of fistulas is associated with developmental defects, inflammatory and tumor processes, injuries and operations. In this regard, fistulas are divided into congenital and acquired. In relation to the environment, a distinction is made between: external, opening onto the surface of the skin; internal, not communicating with the external environment; and combined, when there is communication between the internal organs and the skin, for example, a bronchopleurothoracic fistula, etc. By the nature of the discharge, fistulas are: mucous; purulent, biliary, intestinal, milk, salivary, urinary, etc. Fistulas are also designated by the organ: gastric, intestinal, urinary, bronchial, esophageal, etc.

Congenital fistulas are always lined with epithelium, they are divided into median and lateral, complete and incomplete. Incomplete fistulas, one end of which is obliterated, are called diverticula of the esophagus, bronchus, bladder, ileum/ (Meckel's diverticulum), etc. Congenital fistulas of the neck are most often encountered in practice: median fistulas are associated with developmental anomalies of the thyroid gland; lateral fistulas are of bronchogenic nature. Complete umbilical fistulas are associated with non-closure of the umbilical-intestinal tract or urinary duct with characteristic discharge. They must be differentiated from umbilical cysts, which are characterized by mucous discharge. Epithelial coccygeal tract is often encountered. Given their epithelial lining, they cannot close themselves and require plastic surgery.

Acquired fistulas can be caused by various reasons, but the most common of them are trauma and purulent-inflammatory processes, since pus always tends to break through to the outside. Epifascially located abscesses and deep ones, in cases of corrosion or damage to the fascia; open onto the skin, forming a purulent fistula. If the exit to the skin is difficult for some reason, the abscesses are connected to each other by internal fistulas, an example of which are: ischiorectal, pelviorectal paraproctitis, retropanniculum panaritiums, etc. Pus can break through into adjacent hollow organs or body cavities, forming internal organ or interorgan fistulas, for example, bronchopleural, esophageal-tracheal, etc. Tumors during the period of decay and some types of injuries can also give interorgan fistulas, for example, utero-vesical, interintestinal, vaginal-rectal, etc.

A distinctive feature of acquired fistulas is that they have a granulating wall and do not have an epithelial lining. The fistula persists for a long time due to abundant exudation of pus, secretions, especially active ones. As a result, when the main focus is stopped or the inflammation in it subsides, the fistulas close or close themselves. But when the chronic process in the focus worsens, they open again, which, for example, happens with the fistula form of chronic osteomyelitis.

How are fistulas recognized?

Diagnosis of external fistulas is not difficult. The presence of complaints, anamnesis data, the presence of a hole in the skin with a characteristic discharge allow us to make a diagnosis. Fistulography is performed to determine the nature of the course and its connection with tissues. To determine the course of the fistula during surgery, it is stained with dyes. A laboratory study of the contents of the fistula is indicated.

Fistulas formed by a specific infection have their own characteristics. When lymph nodes or skin abscesses are opened in tuberculosis, the formation of a fistula is accompanied by the formation of an ulcer around it: the surrounding skin is thinned, cyanotic hyperemic, the granulation of the fistula is pale, the openings of the fistulas and ulcers have characteristic bridges, the discharge is "cheesy", they heal with a rough scar, for a short time, after which they quickly recur. Fistulas in actinomycosis are painless, with a scanty discharge in the form of millet grains, around it there is a painless inflammatory infiltrate.

Diagnosis of internal fistulas is very difficult, especially in case of suture failure. Dyes are used primarily, most often indigo carmine or methylene blue, for example, to diagnose a gastric or intestinal fistula, the patient is given 10-20 ml of dye to drink, if there is a fistula, it will be released through the drainage from the abdominal cavity; also, the introduction of dye into the bronchus and its release through the drainage from the pleural cavity indicates the presence of a fistula. But in many cases, it is necessary to conduct a comprehensive examination, including endoscopic and contrast radiographic studies.

A special group consists of artificial fistulas, created intentionally by surgery to restore the patency of a hollow organ, to divert its contents or secretion in the right direction, and to provide nutrition to the body through it. Depending on the indications, two types of artificial fistulas (stomas) are formed: temporary ones, which heal on their own after the need for them has passed, and permanent ones, which are necessary for long-term use. In these cases, epithelial fistulas (labial: complete and incomplete) are created by suturing the mucous membrane of the hollow organ to the skin. The most common stomas are tracheostomies, gastrostomies, colostomies, enterostomies, and cystostomies.