Surgery for sinus mucocele & turbinate reduction done under general require urine cathetor? any danger to this nature of surgery?

Most likely no: There is no reason that you should need a catheter for sinus surgery. The procedure is relatively short in time & often done out-patient. That said, your surgeon will do what s/he feels is proper for the safety of your health. You can always call & ask. Just like intubation for breathing though, they may do it once you are "out" & remove it before you wake so you may not even know it was done.

Not usually: All surgery carries risks. Discuss your specific risks with your doctor before the appointment. You will likely not need catheterization as the procedure is relatively quick and you should be npo (no food or drink) for 6-8 hours prior to the surgery.