MIAMI A homeless man whose face was mostly chewed off in a bizarre, vicious attack faces a bigger threat from infection than from the injuries themselves, according to experts on facial reconstruction. He will require months of treatment to rebuild his features and be permanently disfigured.

Though gruesome, such severe facial injuries are generally not life threatening. The most serious risk to Ronald Poppo as he remained hospitalized Wednesday were germs that may have been introduced by the bites of the naked man who attacked him. One of the 65-year-olds eyes was also gouged out.

The human mouth is basically filthy, said Dr. Seth Thaller, the chief of plastic and reconstructive surgery at the University of Miamis Miller School of Medicine.

To keep the wounds clean, doctors use grafts of the patients skin, cadaver skin or synthetic skin to cover the exposed bone or cartilage. Dr. Blane Shatkin, a plastic surgeon and director of the wound healing center at Memorial Hospital Pembroke in South Florida, said. The coverage would act like a dressing, protecting the wound as it heals.

Poppos lifestyle and health before the attack could determine how doctors proceed and whether they eventually consider a facial transplant, plastic surgeons said. Poppo had been homeless for more than 30 years, previously survived a gunshot wound and faced multiple charges of public intoxication, among other arrests.

You would not just take this guy to the OR for a face transplant you really have to go in a staged fashion. You save what you can and use what you have available first, dont burn any bridges and move forward slowly, Shatkin said. And you have to see what he wants.

Psychological care is important to the recovery, and patients need to participate in the decision-making process, Dr. Bohdan Pomahac, a surgeon at Brigham and Womens Hospital in Boston, said. He performed a facial transplant on a Connecticut woman who was mauled by a friends pet chimpanzee in 2009.

I think the patient has to be able to cope with the injury and the trauma and needs to figure out what has happened. It often takes them weeks to understand what has happened, Pomahac said.

Its not clear why Poppo was attacked Saturday afternoon by 31-year-old Rudy Eugene alongside a busy highway. Police have released few details about the attack, but surveillance video from a nearby building shows Eugene pulling Poppo from the shade, stripping and pummeling him before appearing to hunch over and then lie on top of him.