الفهرس 
3 Anatomy and Embryology of Rectum and Anal Canal…..…Only 14 pages are availabe for public view
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Abstract
SUMMERY & CONCLUSION
Anal fistula is a common proctological problem. It is a common cause of chronic irritation to both patients and surgeons. Treatment failure may be decreased by good appreciation of normal anorectal anatomy and fistula pathoanatomy.
The anal canal is always closed except for the passage of flatus and faeces. It is held closed by sphincter tube of muscles which are in two distinct sphincteric entities; internal (smooth muscle) and external (striated muscle). Anal sphincters are considered the most important factors for maintaining anal continence.
Perianal abscess fistulous disease not associated with a specific systemic disease is most commonly cryptoglandular in origin. The categorization of fistula-in-ano is dependent on its location relative to the anal sphincter muscles according to Parks’ classification: inter-sphincteric, trans-sphincteric, supra-sphincteric, or extra-sphincteric.
Symptoms of fistula-in-ano have been reported to be: Discharge (65%), pain (34%), swelling (24%), bleeding (12%), & diarrhoea (1%). Additional bowel symptoms may be present when the fistula is secondary to proctocoltis, Crohn’s disease, actinomycosis or anorectal carcinoma. The most important initial step in diagnosis is to determine the activity and severity of the disease process. Probing of fistula is an important step for its classification, however the probe should never be forced, only gently maneuvered.
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 does not seem worthwhile.
With 2-D EUS, 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 ultrasonic appearance changes into bright hyperechoic. By comparing the two images, the fistula tract and its extensions could be identified and discriminated from previous scars. 3-D EUS combined with hydrogen peroxide offers extra visualization of perianal fistulae and therefore provides more information than conventional EUS.
Pelvic magnetic 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, recommended in all patients presenting with recurrent fistula. If MR imaging and expertise are available, the best option for preoperative assessment of fistula-in-ano would be to progress straight to MR imaging.
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 is no complex high anal fistula.
For simple low fistula, fistulotomy may be enough, however for high anal fistula, seton fistulotomy provides good results. This method depends on tightening a seton which encircle the striated muscles that lie superficial to the fistula tract. The striated muscle is slowly divided by a process of ischaemic necrosis. This method in remarkably successful in preserving sphincter function.
Fibrin glue has the advantage of minimal risk to continence, however 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 faecal 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 shrinkage of the flap principally caused by inadequate blood supply, the reasons of which might be inadequate dissection, dimension, or tension at suture line.
Electrocauterization of fistula-in-ano is a simple and easy technique without complication and less expensive and could be performed as an outpatient procedure.
Recently described for the treatment of fistula-in-ano, a new technique for fistulotomy with use of the radiofrequency surgical device. The results of radiofrequency fistolotomy are promising, significantly less time-consuming, and more haemostatic since Gupta reported the procedure, which he proposed as ”sutureless fistulotomy”.