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: ENT
[{'content': 'If posterior epistaxis cannot be controlled, which artery is ligated - \nSelect and explain. \nA. Posterior ethmoidal artery, B. Maxillary artery, C. Sphenopalatine artery, D. External carotid artery', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ligation technique is reserved for intractable bleeding where the source cannot be located or controlled by other techniques.\nThe hierarchy of arteries used for ligation is:\n\nSphenopalatine artery\nInternal maxillary artery\nExternal carotid Artery\nAnterior/posterior ethmoidal artery\n\n\nEarlier the most common artery ligated was maxillary artery but now endonasal sphenopalatine artery ligation (ESPAL) is the ligation of choice.\n\n“ESPAL is the current ligation of choice controlling bleeding in over 90% of cases with a low complication rate.”\nTransnasal Endonasal Sphenopalatine Ligation (TESPAL or ESPAL)\n\nIt is the most popular procedure for ligation and has replaced internal maxillary artery ligation.\nCan be done under LA/GA\nIncision is given 8 mm anterior and under the posterior end of middle turbinate\nSphenopalatine artery is ligated in the sphenopalatine foramenQ\nSuccess rate ~100%\nComplications very rare – rebleeding, infection and nasal adhesions\n\nInternal Maxillary Artery Ligation\n\nEarlier it was the ligation procedure of choice for uncontrolled bleeding:\nInternal maxillary artery is ligated in the pterygopalatine fossa using a Caldwell-Luc approach (3rd part of the artery is ligated)Q\nSuccess rate – 89%\nComplications – Sinusitis, damage to infraorbital nerve, oroantral fistula, dental damage and anesthesia, and rarely ophthalmoplegia and blindness.\n\nExternal carotid artery ligation and anterior and posterior ethmoidal artery ligation is not commonly done.', 'role': 'assistant'}]