My dad has been suffering from bleeding from anus, irritation in that area, itching, severe pain, constipation. He says that it hurts down there even when he coughs or sneezes or whenever he tries to urinate. He consulted a gastro today who did his proctoscopy and told him to have a laser fisserectomy on monday. He says that the condition is pretty bad but we have to wait 3 more days for the surgery as my dad was taking blood-thinners (because he had a heart attack in 2016). What worries me the most is that he is complaining of constipation since the last 2-3 days despite of taking laxatives like lactulose syrup and kularsh ayurvedic tablets. My main question is is there any need for a colonoscopy before having surgery to check why is he having constipation? I am worried about it. Is there anything other than fissures which should be checked? And will the doctor put him under sleep before the procedure?