[Frontal sinus anatomical scanographic study of transgender patients for feminization frontoorbitoplasty surgery]. / Étude anatomique scanographique du sinus frontal des patients transgenres en vue d'une chirurgie de frontoorbitoplastie de féminisation.

INTRODUCTION: Little is known about the anatomical elements that allow safe and predictable performance of fronto orbital surgery for facial feminization. The primary objective of this study was to analyze the characteristics (dimensions, pneumatization rate, and anterior wall thickness) of the frontal sinus in MtF transgender patients. The secondary objective was to establish reproducible criteria for CT measurements that could guide preoperative planning of frontal impaction in feminization frontoplasty (FF). MATERIALS: Fifty preoperative facial mass scans of FF surgery patients were included. The mean age of the operated patients was 34 years. The F line represented the ideal forehead tilt in the absence of a frontal hump. RESULTS: The height, width, depth, and thickness of the anterior sinus wall were 26.6mm (±5.7), 49.5mm (±11.3), 10.9mm (±3.3), and 3mm (±0.7), respectively. The mean sinus width to skull width ratio was 0.73 (±0.12). Six percent of patients had bilateral frontal sinus agenesis. An osteotomy of the anterior wall of the frontal sinus was performed in the 64% of patients with frontal sinus projection anterior to the F-line. The emergence of the supraorbital nerves from the frontal bone was through a bony notch in 73.8% of cases. CONCLUSIONS: Knowledge of the anatomy of the frontal sinus and preoperative study of the scans of the facial mass is essential for planning the FF. These characteristics guide the surgical technique of bone remodeling as well as the procedure for releasing the supraorbital nerves.