Each doc is different. My first and 2nd resections were emergency 1 was 1 week after the other so it made for a more complex situation. The 2nd surgery left me with a temporary ostomy so in that case I had to do clears just the day before surgery and nothing after midnight prior to surgery.
I had to have another resection for a fistula and I was able to eat normally then the day before the surgery I had to do a colonoscopy prep (using the pills not the drinks) and was limited to clears only and that was my prep.
good luck to you
Dx with Crohn's 1987, symptoms as early as 1984.
Temp iliostomy February 2007, reversed June 2007, Ovarian cysts, migraines, allergies (incl food allergies) , oral allergy syndrome (diff than true food allergies), Asthma, Gall Bladder removed 1999, Inguenal hernia 1987