Osteoplastic frontal sinus surgery with fat obliteration: technique and long-term results using magnetic resonance imaging in 82 operations.

OBJECTIVE: To evaluate the intraoperative and late complications of osteoplastic sinus surgery with fat obliteration with long-term magnetic resonance imaging (MRI) follow-up.

METHODS: The operative records of all patients who underwent osteoplastic frontal sinus surgery with fat obliteration between January 1, 1986 and December 31, 1997 were reviewed and the postoperative clinical course and magnetic resonance imaging (MRI) scans were analyzed if available. MRI analyses revealed that changes in the distribution of fatty and fibrous tissue, the development of necrosis or oil cysts, recurrences, inflammatory complications, and mucoceles were time-dependent occurrences.

RESULTS: Eighty-two operative records were evaluated and 59 patients were followed 1 to 12 years after surgery. Eighty-six MRI scans in 51 patients were available for analysis. The most frequent intraoperative complications were exposure of orbital fat (19.5%), unintentional fracture of the anterior wall (19.5%), incorrect placement of the anterior wall (17%), and dural injury (9.8%). Persistent changes of the frontal contour (embossment, depression) occurred in 10.2% and the esthetic result was unfavorable in 5.1% of the cases. Mucoceles could be detected in 5 of 51 cases (9.8%). The amount of adipose tissue detectable in the last scan was less than 20% in the majority of cases (53%), and more than 60% in only 18% of the cases. The amount of adipose tissue decreased significantly with time (the median half-life was 15.4 mo).

CONCLUSIONS: Osteoplastic frontal sinus surgery with fat obliteration is very useful and successful in patients in whom the frontal sinus is not accessible via an endonasal approach or the natural drainage cannot be reestablished. MRI is currently the most valuable diagnostic tool to evaluate the frontal sinus after obliteration with adipose tissue. The method has some limitations with regard to detection of small recurrent mucoceles and differentiating vital adipose tissue from fat necroses in the form of oil cysts. In these difficult cases, long-term MRI follow-up is necessary.