Fistula-in-Ano BY

DR.SEFEEN SAFE ATTIA SOHAG TEACHING HOSPITAL

INTRODUCTIONINTRODUCTION

A fistula is an abnormal connection between A fistula is an abnormal connection between two epithelial surfaces. two epithelial surfaces.

The term fistula is derived from the Latin The term fistula is derived from the Latin meaning meaning ““pipe, or flute.pipe, or flute.””

An anal fistula is a tract which usually An anal fistula is a tract which usually

communicates an infected anal gland to a communicates an infected anal gland to a secondary opening in perianal skin, which issecondary opening in perianal skin, which is

lined with granulation tissue.lined with granulation tissue.

ETIOLOGYETIOLOGY

Cryptoglandular disease (anorectal abscesses ) Cryptoglandular disease (anorectal abscesses ) is responsible for 90% of fistula-in-ano. is responsible for 90% of fistula-in-ano.

Anorectal abscesses, represent the Anorectal abscesses, represent the acute presentation of cryptoglandular disease, whileacute presentation of cryptoglandular disease, whilefistulae are the chronic evolution of the same fistulae are the chronic evolution of the same

process. process. Other less common causes of fistulae are Other less common causes of fistulae are

CrohnCrohn’’s disease, trauma, anal fissures,s disease, trauma, anal fissures,carcinoma, radiation therapy, tuberculosis, and carcinoma, radiation therapy, tuberculosis, and

chlamydial infections. chlamydial infections.

Differential Diagnosis of Fistula-in-ano

Nonspecific 90%CryptoglandularSpecific 10%

TraumaForeign bodyObstetricHemorrhoidectomyInflammatory bowel disease

CancerAdenocarcinoma of the rectumSquamous cell carcinoma of the anusLymphoma

InfectiousTuberculosisActinomycosisLymphgranuloma venereumPelvic inflammatory diseaseAppendicitis

Extra-anal sourcesPresacral cystBartholin’s cystPilonidal diseaseHidradenitis suppurativa

Anorectal Abscess Anorectal abscesses arise from obstruction of

the anal glands and ducts,which communicate with the anal crypts located at

the dentate line. The resulting infection begins in the space

between the internal and external sphincters and can spread through the perianal spaces, forming pockets of purulent material.

Locations of anorectal abscesses include (in order of frequency) (1) perianal, (2) ischioanal,

(3) intersphincteric, (4) supralevator

The location and course of the The location and course of the fistula typically reflects the location fistula typically reflects the location of the original abscess:of the original abscess:

(1) intersphincteric(1) intersphincteric

(2) transsphincteric(2) transsphincteric

(3) suprasphincteric(3) suprasphincteric

(4)extrasphincteric(4)extrasphincteric

((55))subcutaneoussubcutaneous

CLASSIFICATIONCLASSIFICATION

fistulae are classified as either simple orcomplex .

Simple fistulae are considered to be intersphincteric or low transsphincteric

<(30% sphincter compromise .)Fistulotomy is the best treatment for this kind of fistula, and is notexpected to put a patient’s continence at risk .

Complex fistulae involve more than 30% of thesphincter and usually are transsphincteric, suprasphincteric, or extrasphincteric.

SymptomsSymptoms

History of an abscess that was either History of an abscess that was either drained spontaneously or surgically. drained spontaneously or surgically.

Intermittent or continuous discharge. If itIntermittent or continuous discharge. If it

is intermittent, the patient may have is intermittent, the patient may have increased pain and pressure prior to increased pain and pressure prior to recurrent drainage, which gives relief. recurrent drainage, which gives relief.

Other symptoms include bleeding, Other symptoms include bleeding, soreness, pruritis or perianal dermatitis.soreness, pruritis or perianal dermatitis.

Physical ExaminationPhysical Examination

InspectionInspectionThe external opening can be seen as an The external opening can be seen as an elevation of granulation tissue dischargingelevation of granulation tissue discharging

pus. (This may be elicited on the digital rectal pus. (This may be elicited on the digital rectal examination) Scar from earlier procedures examination) Scar from earlier procedures maymay

be appreciated as well as chronic skin be appreciated as well as chronic skin changes such as thickened and redness changes such as thickened and redness from persistentfrom persistent

drainagedrainage . .

PalpationPalpation

Digital rectal examination may reveal an Digital rectal examination may reveal an indurated cord-like structure beneath the skin in indurated cord-like structure beneath the skin in thethe

direction of the internal opening. direction of the internal opening. Inability to palpate the fistula tract implies a Inability to palpate the fistula tract implies a

deeper coursedeeper courseand therefore higher transsphincteric fistula. and therefore higher transsphincteric fistula. Internal openings may be felt as indurated Internal openings may be felt as indurated

nodulesnodulesor pits that correspond to enlarged papilla, leading or pits that correspond to enlarged papilla, leading

to a thickened tract.to a thickened tract.

AnoscopyAnoscopy

This examination allows visualization of the This examination allows visualization of the dentate line for possible identification of internaldentate line for possible identification of internal

openings before surgery, as well as identification of openings before surgery, as well as identification of other pathology such as Crohnother pathology such as Crohn’’s disease ors disease or

carcinoma.carcinoma.

GoodsallGoodsall’’s rule, which states that external s rule, which states that external openings located posteriorly to the coronal line openings located posteriorly to the coronal line are associated with tracts that curve to the are associated with tracts that curve to the posterior midline before entering the anal canal. posterior midline before entering the anal canal. external openings anterior to the coronal line external openings anterior to the coronal line track straight toward the internal opening of the track straight toward the internal opening of the anal canal. anal canal.

Radiological EvaluationRadiological Evaluation

Radiology has a limited role in the Radiology has a limited role in the evaluation of anal fistulaeevaluation of anal fistulae . .

Most cases can be diagnosedMost cases can be diagnosed

and treated based on clinical and treated based on clinical examinationexamination . .

Radiological examinations are useful Radiological examinations are useful in atypical cases or after reccurencesin atypical cases or after reccurences

FistulographyFistulography

Fistulography involves cannulation of the Fistulography involves cannulation of the external opening with injection of water external opening with injection of water soluble contrastsoluble contrast

It may be useful for evaluation of recurrent It may be useful for evaluation of recurrent or complex fistulae.or complex fistulae.

Its use has been generally discouraged Its use has been generally discouraged because of risk of septicemia in a small because of risk of septicemia in a small amount of patients and poor visualization of amount of patients and poor visualization of anatomic landmarks. anatomic landmarks.

This study has been substituted by other This study has been substituted by other diagnostic modalities diagnostic modalities

CT ScanCT Scan

CT scan has a minor role in the CT scan has a minor role in the assessment of anal fistulae. assessment of anal fistulae.

The main use of CT scan is toThe main use of CT scan is todistinguish an abscess requiring drainage distinguish an abscess requiring drainage

from perirectal cellulites. from perirectal cellulites. It is done with intravenous and rectal It is done with intravenous and rectal

contrast. contrast. It may be useful if MRI is not available or It may be useful if MRI is not available or

contraindicatedcontraindicated

Endoanal UltrasoundEndoanal Ultrasound

The role of ultrasound is toThe role of ultrasound is to: :

11--Identify the fistula tract in relation to the internal Identify the fistula tract in relation to the internal and external sphinctersand external sphincters

22--To determine if the fistula is simple or complex 3-To determine if the fistula is simple or complex 3-Define the location of the internal openingDefine the location of the internal opening

The injection of hydrogen peroxide into the fistula The injection of hydrogen peroxide into the fistula opening during ultrasound improvesopening during ultrasound improves

identification of fistulae and their internal openings identification of fistulae and their internal openings by making them hyper instead of hypoechoicby making them hyper instead of hypoechoic..

Magnetic Resonance ImageMagnetic Resonance Image

Accurate classification of fistulae with MRI is Accurate classification of fistulae with MRI is possible in 89% of patients compared to 61% possible in 89% of patients compared to 61% using 2-D anal ultrasoundusing 2-D anal ultrasound..

Although MRI seems superior to endoanal Although MRI seems superior to endoanal ultrasound in the assessmentultrasound in the assessmentof fistula-in-ano, anal ultrasound tends to be more of fistula-in-ano, anal ultrasound tends to be more useful than MRI because it is more widelyuseful than MRI because it is more widelyavailable, can be performed quickly in the office available, can be performed quickly in the office setting, and is less expensivesetting, and is less expensive

MRI is therefore best reserved for cases where MRI is therefore best reserved for cases where ultrasound has already failed to identify the ultrasound has already failed to identify the fistula and internal openingfistula and internal opening

Locating the fistuloustract. The probe iscarefully inserted through the external opening, and allowed to follow the tract until

it exits through the

internal opening.

This will serve as a guide for eithersubsequent fistulotomyor seton placement

Fistulotomy

After gently passing a probe down the tract through the external opening an incision may be made on the probe using a scalpel or electrocautery through the perianal skin and rectal mucosa .

The edges of the tract should be excised completely ,and care should be taken not to undermine the edges

Once open, the fistulous tract should be cleaned with a curette to remove any granulation tissue .

At the completion of the procedure, light packing tape may be placed in the fistula tract

Seton PlacementSeton Placement

Cutting setonsCutting setons will gradually cut through the sphincter muscle via pressurewill gradually cut through the sphincter muscle via pressurenecrosis, with fibrosis behind the seton, preventing sphincter necrosis, with fibrosis behind the seton, preventing sphincter retraction and incontinenceretraction and incontinence..A large Ethibond or other braided suture is placed through theA large Ethibond or other braided suture is placed through theinternal and external openings of the fistulous tract and tied internal and external openings of the fistulous tract and tied down onto the sphincter complexdown onto the sphincter complex..

The seton will then be The seton will then be ““advancedadvanced”” over the course of the over the course of thenext several weeks until the fistulous tract is completely next several weeks until the fistulous tract is completely incisedincised . .care must be taken to not advance the seton too quicklycare must be taken to not advance the seton too quickly, ,

as the patient will experience a tremendous amount of pain asas the patient will experience a tremendous amount of pain aswell as suffer a complication of sphincter divisionwell as suffer a complication of sphincter division..

Draining setonsDraining setons will keep the fistulous tract open, allowing for abscess drainagewill keep the fistulous tract open, allowing for abscess drainageand tract maturation, therefore facilitating a future fistulotomy or other and tract maturation, therefore facilitating a future fistulotomy or other advancedadvancedfistula closure technique. A vessel loop or large Ethibond suture is passedfistula closure technique. A vessel loop or large Ethibond suture is passedthrough the internal and external openings of the fistulous tract and tied through the internal and external openings of the fistulous tract and tied loosely around the sphincter complexloosely around the sphincter complex. .

indications for use of a draining seton includeindications for use of a draining seton include: : ((11 ) )complex anorectal fistula extensively involving the externalcomplex anorectal fistula extensively involving the external

sphincter, with the goal of staged fistulotomy; (2) complex anorectal fistula insphincter, with the goal of staged fistulotomy; (2) complex anorectal fistula inthe setting of sepsis; (3) anterior high transsphincteric fistula in a female the setting of sepsis; (3) anterior high transsphincteric fistula in a female patientpatient;;

((44 ) )high transsphincteric fistula in a patient with AIDS; (5) long-term fistulahigh transsphincteric fistula in a patient with AIDS; (5) long-term fistulatreatment in a patient with active IBD; and (6) concern for fistulotomy leading treatment in a patient with active IBD; and (6) concern for fistulotomy leading to fecal incontinenceto fecal incontinence

Draining setonDraining seton

The seton placedThe seton placed

through the external through the external and internal and internal fistulafistula

openings and tiedopenings and tied

loosely to maintainloosely to maintain

drainagedrainage..

Fibrin GlueFibrin Glue

Fibrin glue may be used as an alternative means of occluding the Fibrin glue may be used as an alternative means of occluding the fistulous tractfistulous tract . .

Following digital rectal examination, the fistulous tract is identified andFollowing digital rectal examination, the fistulous tract is identified andany granulation tissue at the internal or external openings is gently any granulation tissue at the internal or external openings is gently debrided with a curettedebrided with a curette . .

Fibrin glue is then gently injected through the external openingFibrin glue is then gently injected through the external opening until the tract is fulluntil the tract is full . .

Success of this technique is variable, with long-term healing reported at Success of this technique is variable, with long-term healing reported at 3131––60%60%However, it can be used to avoid a large operation in risky patientsHowever, it can be used to avoid a large operation in risky patients

Fibrin glue is an activated mixture of solution containing fibrinogen, Fibrin glue is an activated mixture of solution containing fibrinogen, factor XIII, fibronectin, and aprotininfactor XIII, fibronectin, and aprotininWhen applied to the fistula tract, the fibrin clot seals the tract and When applied to the fistula tract, the fibrin clot seals the tract and stimulates migration, proliferation, and activation of fibroblastsstimulates migration, proliferation, and activation of fibroblasts..

Anal Fistula PlugAnal Fistula Plug

This fistula plug made from lyophilized This fistula plug made from lyophilized porcine intestinal collagen is designed to porcine intestinal collagen is designed to occlude the fistula tract from the internalocclude the fistula tract from the internal

to the external openingto the external opening . .

The plug provides a scaffold for theThe plug provides a scaffold for the

ingrowth of native tissueingrowth of native tissue . .

Advantages of this technique are the Advantages of this technique are the mechanical stable configurationmechanical stable configuration,,

Endorectal Advancement FlapsEndorectal Advancement Flaps

Endorectal advancement flaps were first Endorectal advancement flaps were first described by Noble 1902described by Noble 1902 , ,

This treatment modality consists of removal This treatment modality consists of removal and patching of the internal openingand patching of the internal opening

with a muscularwith a muscular––mucosal flap of rectal wallmucosal flap of rectal wall . .

Island Flap AnoplastyIsland Flap Anoplasty

Dermal island advancement flap (anocutaneous Dermal island advancement flap (anocutaneous advancement flap). Its use in the treatment of advancement flap). Its use in the treatment of fistulae started in the pastfistulae started in the pastdecade, basically to avoid incontinence and decade, basically to avoid incontinence and mucosal ectropion after mucosal flap mucosal ectropion after mucosal flap advancementadvancement..

This procedure has been reported forThis procedure has been reported forcomplex or recurrent casescomplex or recurrent cases . .

There are good results in terms of healing, There are good results in terms of healing, postoperative complications, pain, and postoperative complications, pain, and incontinenceincontinence . .

Post-operative CareAfter Fistulectomy

wound irrigations are recommendedthree to four times daily. In order to promote the healingfrom the depth of the wound, The wound must be kept clean.

A post-operative antibiotic treatmentWeekly inspection should be carried out by the surgeon.Silver nitrate may be applied to prevent overgranulation .Sphincter function must be evaluated soon after surgery ,

Bulky laxatives must be given to allow passage of stools without straining and to reduce pain .

Non-steroidal anti-inflammatory drugs are useful to reduce local pain.

Results and ComplicationsAfter Treatment

Satisfactory results may be achieved in the treatment ofanal fistula. Results depend on the type of fistula. Thehealing time varies from 6 weeks for the low type to

16 weeks or more for the complex variety .Fistula surgery should be reserved for experienced surgeons inorder to reduce as much as possible the high incidenceof recurrence and prevent incontinence .

Two main post-operative complications may occur after treatment of an anal fistula :

recurrence and incontinence

Recurrence

Recurrence of anal fistula in cases of cryptoglandular origin is essentially due to failure to remove the correct anal gland .

The internal opening may not be foundand part of the tract may be buried under the granulation tissue, including the epithelial remnantsA recurrence rate of up to 10% is observedIf a fistula has been adequately treated and still recurs, the possibility of Crohn’s disease must be considered.

Incontinence

Partial early post-operative incontinence is frequentafter surgery of any fistulous tract and is the result ofinflammation, tissue deformity and painIf the sphincter has been divided, the initialweakness regresses, and continence has proved to beadequate within 2–3 weeks.

As many as one-third of the patients have some permanent disturbance in anal continence ,varying from loss of flatus control to severe faecal incontinence .

To prevent incontinence, there must be a sufficient time interval between the two operative sessions in a two-stage procedure .Division of the sphincter muscle must be kept to a minimum .

If sphincter division results in persistent incontinence,sphincter repair must be considered