One of the original contouring procedures in facial feminization surgery is that of reshaping the forehead. Brow bone reduction still remains one of the defining facial contouring procedures that separates male vs. female appearance. It is a well described technique that fundamentally can be done by either burring reduction or a bone flap setback technique. The thickness of the overlying cortical bone combined with how much reduction is needed determines which of the two techniques is needed for the desired aesthetic outcome.
Determining the shape of the underlying frontal sinus anatomy and anterior bony table thickness is usually done with preoperative x-rays. This allows the very variable extent of the frontal sinuses, which is never the same on each side of the midline and may even be partially absent in some people, to be known beforehand and help guide both brow bone reduction procedure selection as well as its execution.
In the August 2019 issue of the JAMA Facial Plastic Surgery an article was published entitled ‘Frontal Sinus Transillumination in Cranioplasty for Facial Feminization Surgery’. In this paper the authors describe a frontal sinus transillumination technique for demonstrating the boundaries of the frontal sinus and its overlying bone thickness.
Transillumination can be a substitute for preoperative 3D CT scanning of the forehead to delineate frontal sinus anatomy. It could certainly be useful when doing a burring reduction of the frontal table of the sinus wall so one knows when it is getting thin.
Even when doing a bone flap removal, knowing the actual boundaries of the frontal sinus can help one position the osteotomy locations as well as where is the intersinus bony septum.
Dr. Barry Eppley