There are many ways to categorize anal fistula, according to the internal and external mouth classification; according to the relationship between fistula and anal sphincter classification; according to the shape of the fistula classification; according to the fistula deep, shallow, branch classification; according to the pathology, etiology classification, etc., the above various classification methods, are used for clinical. However, it is more common to use the classification method of fistula depth, superficiality and branching. Now the country has developed a unified classification method, has a strong scientific, representative and authoritative. Now the various classification methods are introduced as follows. (A) according to the internal and external mouth classification
1, internal and external fistula: internal mouth in the anal sinus, the external mouth in the anus, borrow a fistula to make the internal and external white communication.
2, internal half fistula: only the internal mouth, fistula, no external mouth.
3, external half-fistula: only the external mouth, fistula, no internal mouth.
4, internal fistula, the two openings of the fistula are in the tooth line, borrow a fistula to communicate. This kind of fistula is mostly submucosal fistula.
5. External fistula: the two openings of the fistula are in the anal skin, through a fistula. This kind of fistula is mostly subcutaneous fistula. (B) according to the fistula and anal sphincter relationship classification
1, shallow intermuscular fistula: internal mouth in the anal sinus, the external mouth in the anus, the fistula in the external anal sphincter superficial and subcutaneous layer through.
2, deep intermuscular fistula: internal mouth in the anal sinus, external mouth outside the anus, the fistula tract in the external anal sphincter between the superficial and deep layers through.
3, extra-muscular fistula: internal mouth in the anal sinus, external mouth in the anus, the fistula passes between the subcutaneous layer of the external anal sphincter and the anal subcutaneous.
4, intramuscular fistula: internal mouth in the rectal mucosa, external mouth in the anal sinus, fistula passage between the internal anal sphincter and the rectal submucosa.
5, the fistula on the anorectal muscle: the internal mouth in the anal sinus, the external mouth in the external anus, the fistula passes through the anorectal muscle, through the pelvic rectal space. (C) according to the shape of the fistula channel classification
1, straight fistula; pipe vertical, internal and external mouth opposite, forming a straight line.
2, curved fistula: pipe line curved, internal and external mouth is not relative.
3, horseshoe fistula
(1) anterior horseshoe fistula: the internal mouth in the anal canal before the middle of the anal sinus on both sides, the external mouth in the anus before the transverse line of the perineum on the left and right sides, the two fields of fistula around the anterior half of the circle of the anus and the internal mouth.
(2) after the horseshoe-shaped fistula: the internal mouth in the anal canal after the middle or slightly biased to the left and right sides of the anal sinus, the external mouth in the anus after the transverse line of the left and right sides, the two sides of the fistula around the anus after the half-ring with the internal mouth. (D) according to the fistula deep, shallow, branch classification
1, low simple anal fistula; only a fistula, and through the external sphincter deep below, the inner mouth in the anal sinus near.
2, low complex anal fistula: fistula tube below the deep external sphincter, the external mouth and fistula tract has more than two, the internal mouth in the anal sinus area.
3, high simple anal fistula: only one fistula, fistula through the sphincter deep above, the internal mouth is located in the anal sinus area.
4, high complex anal fistula: there are more than two external mouth and fistula with branches, its main tube through the external sphincter deeper than, there are one or more than two internal mouth. (E) according to the etiology, pathology classification
1, non-specific anal fistula (i.e., purulent anal fistula): is the most common anal fistula, usually more than Escherichia coli, staphylococcus, streptococcus, etc. caused by an acute infection, local redness, swelling, heat, pain is obvious, the pus is mostly yellow, viscous.
2, specific anal fistula: can be divided into tuberculosis and actinomycosis anal fistula, the former is tuberculosis infection, the latter is actinomycosis infection. Such anal fistula local redness, swelling, heat, pain is not obvious, pus more thin, cheese-like secretion out, or mixed with uniform rice size sulfur-colored waist particles. (F) the national unified classification criteria
1, low simple anal fistula; only a tube, and is located below the anorectal ring.
2, low complex anal fistula: with more than two tubes, located below the anorectal ring, and more than two external or internal mouth.
3, high simple anal fistula: only one tube, through the anorectal ring or on it.
4, high complex anal fistula: there are more than two ducts, located above the rectal ring of the anal canal, and there are more than two external or internal orifices.