This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anal Canal, Subject name: Surgery
[{'content': 'Treatment of choice for low fistula in ano is - \nSelect and explain. \nA. Fistulotomy, B. Intravenous antibiotics, C. Staged surgical resection, D. None of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e. Fistulotomy * A fistula in ano is a track, lined by granulation tissue, that connects deeply in the anal canal or rectum and superficially on the skin around the anus.* It usually results from an anorectal abscess (cryptoglandular abscess)* Other causes are:# Crohn's ds., malignancy, radiation, tuberculosis, actinomycosis, chalamydia inf* It is divided into 2 types - high & low, according to whether their internal openings is below or above the anorectal ring.* The importance of deciding whether a fistula is a low or a high type is that a low level can be treated by fistulotomy (opening the tract) without causing damage to the sphincter.* High level fistulas can be treated only by 'staged' operation as there is risk of incontinence.", 'role': 'assistant'}]