Use of bone for obliteration of the nasofrontal duct with the osteoplastic flap: a cat model.

The management of the frontal sinus remains controversial for traumatic and inflammatory disease. The osteoplastic flap with fat obliteration has become the treatment standard, although late failures with infection and mucocele formation may arise. Theories for mucocele formation include regrowth of residual mucosa from the sinus and ingrowth of mucosa from a nonobliterated nasofrontal duct. A study to evaluate the means of nasofrontal duct obliteration was developed. Three cat groups were evaluated at 1, 2, and 3 months. Group 1 had the duct and sinus obliterated with fat. Group 2 had the duct obliterated with bone and the sinus with fat. Group 3 had only the duct obliterated with bone. There was no mucosal ingrowth in any of the sinuses for the intervals studied. In group 1, fat volume was seen to decrease over time with replacement by fibrous tissue within the duct. Groups 2 and 3 developed progressive obliteration of the duct with new bone formation. One may infer that fat obliteration alone does not provide a predictable stable situation as fat atrophies within the duct and may allow mucosal ingrowth. Bone obliteration was shown to be progressive within the duct from osteogenesis. This is the first experimental model to correlate clinical observations of the use of bone for sinus obliteration. This study concluded that bone obliterates the nasofrontal duct better than the accepted standard of fat, independent of the material used to obliterate the sinus.