MAGNETIC-RESONANCE-IMAGING AFTER FRONTAL-SINUS SURGERY WITH FAT OBLITERATION

The obliteration of the frontal sinus via an osteoplastic approach is performed with the aim of achieving a permanent 'switching off' by fin al and conclusive clearing out. For this, freshly harvested abdominal fat has shown itself to be the best clinically. It is possible to demo nstrate the vitality of fat transplanted into the frontal sinus withou t an operation i.e. by a macroscopical and histological examination us ing magnetic resonance imaging (MRI). The magnetic resonance examinati ons were carried out on a supraconductive 0.5 T Magnet (Gyroscan T.S.I I, Philips Medicine Systems, Eindhoven, Netherlands) with a quadrature (square) head spool. We produced T-1-weighted spin echo images (TR: 4 50-550 ms; TE: 20-25 ms), T-2-weighted fast spin echo images or in dou ble-echo technique in transverse orientation (Turbo SE or TR: 2000-250 0 ms; TE: 50-90 ms) and short tau inversion recovery (STIR) sequences for fat suppression (TJ: 140 ms; TR: 1400 ms; TE: 30 ms). The fat impl anted into the frontal sinus of 11 patients aged 22-65 years, having u ndergone an osteoplastic frontal sinus operation with obliteration, wa s examined post-operatively by MRI. Objectives were the time-dependent distribution of portions of vital fatty or connective tissue, the eve ntual development of necroses or cysts as well as recurrences, inflamm atory complications or re-epithelization of the frontal sinus four to 24 months postoperatively. In only six out of 11 cases was vital fatty tissue found. Fatty necrosis occurred five times,whereas in four case s a transformation into granulation tissue and in one case into connec tive tissue could be seen. All 11 patients were complaint-free. Long-t erm observations are needed to see if differences in the recurrence ra te of frontal sinus disease are dependent on whether the implanted fat remains vital or necrosed and transformed.