الفهرس 
EMBRYOLOGY OF RECTUM AND ANAL CANALOnly 14 pages are availabe for public view
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Abstract
The fistula is an abnormal communication between two epithelial lined surfaces, it is lined by granulation tissue, that is why it persists. The cryptoglandular hypothesis is the most accepted theory in the pathogenesis of the anal fistulae also there are some other causes e.g. Crohn’s disease, ulcerative colitis, T.B, actinomycosis, foreign body, lymphogranuloma venereum and trauma. The estimated incidence among population is about 1: 10.000 and male to female ratio is about 2:1 and 4:1. In the standard classification of anal fistulae, the fistulae are classified into two groups; low level fistulae in which the internal opening below the anorectal ring, and high level fistulae in which the internal opening at or above the anorectal ring, but the most widely used classification is that of Parks’ in which the anal fistulae are classified into; intersphincteric fistulae in which there are simple and complicated, trans-sphincteric fistulae in which there are simple and complicated, suprasphincteric fistulae and extrasphincteric fistulae.
Diagnosis of anal fistulae is by symptoms: purulent discharge, bleeding, diarrhea and pruritis but if the orifice is occluded the pain is present and increases until the discharge erupts. Signs: sexternal opening, induration a long the track and internal opening may be identified by rectal examination or proctoscopy. Fistulography may be helpful but it was found inaccurate in about 84% of cases.
Computerized tomography has no convincing evidence of improvement in management, anal ultrasonography is not yet widely used. The role of MRI (magnetic resonance imaging) can accurately identify the internal opening reaching up to 85% and the abscesses in about 100% and if it is done in recurrent fistulae reduces further recurrence from 52% to 13%. Treatment of high anal fistulae is surgical except in those circumstances of unusual aetiology such as Crohn’s disease or TB which can be treated by treatment of the cause, in surgical treatment many various methods have been devised to preserve the external sphincter complex, the multiplicity of techniques reflects their relative lack of success, fistulotomy and fistulectomy are suitable only for low anal fistulae, however, fistulotomy is better.
Fistulectomy by core out technique is suitable for high anal fistulae but not for recurrent or more complex fistulae, rerouting method is technically difficult and necessitates more than one sitting, seton technique whether two stage fistulotomy or cutting seton are equally have recurrence rate of about 8% and partial loss of continence of about 66% in treatment of high anal fistulae, however, 44% may heal spontaneously after removal of loose seton, with partial loss of continence of about 17%.
The results of chemical seton are comparable with conventional surgery. Advancement flap and core out fistulectomy technique has a recurrence rate of about 7% and partial loss of continence of about 8%, but it is technically difficult and the flap may undergo necrosis.
Fibrin glue may be used in high fistulae with success rate of about 70% and recurrent fistulae with success rate of about 60%, it has no advantage over fistulotomy in simple fistulae, but it healed more complex fistulae than other techniques and with higher patients satisfaction.