![]() ![]() No single factor can be attributed to the etiopathogenesis of anal fissures, and a combination of factors may be contributory. It has also been found that there is a decrease in the normal spontaneous cyclical anal sphincter relaxation in patients with anal fissure. 1989) and hence the increased propensity of occurrence of anal fissures in this region. The blood supply to the posterior midline of the anal canal has been demonstrated to be significantly lower using Laser Doppler Flowmetry than anywhere else in the anal canal (Klosterhalfen et al. In 1994, a theory of inverse relationship of anodermal blood flow in the posterior commissure of the anoderm to the internal sphincter resting pressure was postulated by Schouten et al. It was known for a long time that the tear in anal fissure is caused by passage of hard fecal mass. The etiology and pathogenesis of this condition is poorly understood and hence the confusion in the choice of optimal modality of treatment. Eventually after several months, the muscle may become fibrosed in its spastic condition so that a rather fibrotic, tightly contracted, internal sphincter may result. When the fissure is relatively superficial, the sphincter usually undergoes a tight spasm, but when the fissure deepens and bares the sphincter fibers, this becomes even more pronounced. Usually the external opening of this fistula lies in or close to the midline, a short distance behind the anus, and an anal fissure should always be thought of as the most common cause of such a median low dorsal anal fistula. At any stage, frank suppuration may occur and extend into the surrounding tissues to form a perianal abscess, which may discharge through the fissure into the anal canal or may burst externally to produce a low anal fistula: fissure fistula complex (Fig. ![]() Another feature in a long-standing case is the development of fibrous induration in the lateral edges of the fissure. Quite frequently, the anal valve immediately above the fissure also becomes swollen due to edema and fibrosis and forms a hypertrophied anal papilla. Atypical fissures are located at any other site and usually due to some secondary pathology. Among the typical sites, posterior fissures are the most common (90 %), while anterior ones are uncommon. Based on location, fissure is classified as typical or atypical. 4.5), induration of the lateral edges of the fissure, relative stenosis secondary to spasm, or fibrosis of the internal sphincter are labeled as chronic, and these often require surgical management (Zaghiyan and Fleshner 2011 Madalinski 2011). Fissures which have not healed in 6 weeks and developed secondary changes in the form of sentinel tag, hypertrophied anal papilla (Fig. They are superficial and may deepen to expose the underlying internal sphincter. ![]() Typically acute anal fissures are those which heal within 6 weeks of duration spontaneously or with medical management. It has also been classified arbitrarily as acute fissure in ano and chronic fissure in ano based on the duration of symptoms and healing. Fissures may be classified as primary idiopathic, which is the most common and secondary, based on the etiology. ![]()
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