The following is from an article on UFCDaily.com:
UFCDaily.com has learned exclusively that Mirko 'Crocop' Filipovic successfully went through surgery which involved straightening his nasal cartilage on Sept. 28. Ever since his debut in UFC, his cartilage has been twisted, which prevented him from breathing properly, thus, 'Crocop' always fought with his mouthpiece slightly out of his mouth.
Crocop said “When I went up to the doctor, he didn't believe the state my nose was in. He didn't even believe that I was an athlete. He said that my nose would account for at least a 50% decrease in my stamina.” CroCop also removed the small UFC-cage he had in his house; he decided to switch to the official-size cage.
“I had trouble determining the distance when I fought in the bigger cage; now I am properly training for that.” Crocop still says that he will challenge for the UFC belt.