الفهرس 
EmbryologyOnly 14 pages are availabe for public view
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Abstract
Anal fistula is a common proctological problem. It is a common cause of chronic irritation to both patients and surgeons.
Treatment failure rates may be decreased by good appreciation of normal anorectal anatomy and fistula pathoanatomy.
Radiographic investigations have a limited role in evaluation of fistula-in-ano, most primary fistulae can be treated on the basis of clinical examination alone. However, when atypical features are present or when prior surgery has failed, radiographic evaluation may be useful in selected cases.
Fistulography can reveal the depth and the branches of the tracks. However, the injection of the dye under high pressure carries the risk of sepsis dissemination. Fistulography may be helpful to outline an extra-sphincteric track, otherwise fistulography may doesnot seem worthwhile.
With Three Dimension Endoanal Ultrasound, fistula tract is visualized as tube-like hypoechoic lesion, when hydrogen peroxide 3% is introduced into the fistula tract it generates small air bubbles, the ultrasonographic appearance is changed into bright hyperechoic. By comparing the two images, the fistula tract and its extensions could be identified and discriminated from previous scars.
Pelvic Magnatic Resonance Imaging is accurate in identifying perianal fistula, as it was shown that fistula surgery guided by MRI reduced the recurrence of anal fistula by 75% and therefore, recommened in all patients presenting with recurrent fistula. Performing MRI with contrast allows discrimination of fistulous tracts from adjacent structures.
Surgical strategies to treat anal fistula tend to be guided by their degree of complexity and their underlying aetiology.
Drainage of acute abscess with primary anal fistulotomy should be reserved for cases in which an internal opening is easily identified and in which there isnot a complex high anal fistula.
For simple low fistula, fistulotomy and lay open may be enough. But for high anal fistula, seton fistulotomy provides good results. This method depends on tighting a seton which encircle the straited muscles that lie superficial to the fistula tract. The striated muscle is slowly divided by a process of ischaemic necrosis, this method in remarkably success in preserving sphincter function.
Electrocauterization for fistula-in-ano is a simple and easy technique without complication and less expensive, could be performed as an outpatient procedure.
Fibrin glue has the advantage of minimal risk to continence, but it offers a little benefit over other methods in terms of complex fistula healing. The precise role of fibrin glue in the treatment of anal fistula remains unclear due to lack of good quality clinical trials.
Advancement flap technique has become a popular technique to minimize the incidence of fecal incontinence. There are different types of advancement flaps like (V-Y advancement flap and island flap).
The main problem in flap advancement surgery is the shrinking of the flap principally caused by inadequate blood supply, the reasons for that might be inadequate dissection, dimension or tension at suture line.