There are two issues really. 1) Metal piercings can create an electrosurgical burn risk if they come in contact with ground. But for rhinoplasty, this is more theoretical than actual since you're on your back (i.e., navel piercing facing up), and most surgeons would hopefully be using bipolar cautery rather than monopolar...thus further reducing the risk. 2) The skin tract from a navel piercing takes a long time to epithelialize (line itself with skin)...much longer than an ear piercing, for example. So if there is still a contaminated wound along the piercing tract at the time of surgery it poses a small, but likely tiny, risk of infecting the nasal wound through a transient bacteremia. Again, this is probably more theoretical than actual since the nose wound itself is more highly contaminated and infection is still rare. But why not simply wait until well AFTER the rhinoplasty to get the navel piercing? All the best, --DCP