This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Lateral internal sphincterotomy is useful for: September 2007 \nSelect and explain. \nA. Anal fistula, B. Anal canal strictures, C. Haemorrhoids, D. Anal fissure', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D: Anal fissure Lateral internal sphincterotomy is the preferred method of surgery for persons with chronic anal fissures, and is generally used when medical therapy has failed. It is associated with a lower rate of side effects than older techniques such as posterior internal sphincterotomy and anoplasty, and has also been shown to be superior to topical glyceryl trinitrate (GTN 0.2% ointment) in long term healing of fissures, with no difference in fecal continence.', 'role': 'assistant'}]