BEHAVIOR OF FATTY TISSUE IN THE OBLITERAT ED FRONTAL-SINUS

The purpose of obliterating the frontal sinus is to provide a permanen t solution to the underlying problem. The material of choice for oblit eration is freshly removed abdominal fat. Using magnetic resonance ima ging, one can assess the vitality of fat tissue in an obliterated fron tal sinus without surgery. Eight patients ranging in age from 22 to 65 years underwent osteoplastic frontal sinus surgery with fat obliterat ion. The freshly implanted abdominal fat was postoperatively investiga ted using magnetic resonance tomography. The magnetic resonance examin ations were carried out on a supraconductive 0.5 T Magnet (Gyroscan T S II, Philips Medicine Systems, Eindhoven, Netherlands) with a square head spool. We produced T-2-weighted spin echo images (TR: 450 - 550 m s, TE: 20 - 25 ms), T-1-weighted fast spin echo images or in double ec ho technique in transverse orientation (Tube SE or TR-2000-2500 ms, TE : 50, 90 ms) and STIR sequences for fat suppression (Tj: 140 ms, TR: 1 400 ms, TE: 30 ms). Our goal was to determine the time-dependent distr ibution of vital fat or fibrous tissue, development of necrosis, cysts , recurrences, inflammatory complications, or re-epithelization of the frontal sinus. Six to 24 months postoperatively, we found vital fat t issue in only three of eight cases. In the other five cases fat necros is was present. The frontal sinus was filled by granulation tissue or fibrous tissue (once). It is not yet possible to determine when the fa t changes to connective tissue. This process varies between individual patients. All eight patients were free of symptoms. Long term examina tion is required to determine whether the recurrence rate of frontal s inus disease depends on the vitality of the transplanted fatty tissue.