Background
Reduction or reshaping of the brow bones is performed either to achieve a facial feminization effect or to soften an overly masculine forehead appearance. Although the brow bone spans the entire forehead, its thickness and shape vary across the supraorbital ridge. The most noticeable projection typically occurs in the medial half near the glabella (frontonasal junction). Interestingly, while this area appears most prominent, it is also where the bone is thinnest.
The unique feature of brow bone anatomy is that the medial brow region overlies the frontal sinus. The development of these sinuses, which occurs after puberty, determines the external contour of the brow. This growth is sexually dimorphic: in men, the frontal sinuses typically produce a distinct protrusion and a more sloped forehead profile, while in women, the forehead appears flatter and more vertical. Because the medial brow bones are composed mainly of an air cavity with a thin bony covering, the more prominent the brow, the larger the underlying sinus.
In forehead feminization surgery, brow bone reduction is a key component. The chosen technique depends on the thickness of the bone over the frontal sinus. If 3–4 mm of reduction can be achieved without exposing the sinus cavity, a burring or shaving technique (Type 1 reduction) can be used. This involves recontouring with a high-speed rotary instrument, carefully monitoring bone thickness to avoid penetrating into the sinus. While this is not the most common approach, it is appropriate for carefully selected patients, typically men with moderate brow projection.
Case Presentation
This male patient had a typical male brow contour, not excessively protrusive overall. However, in certain lighting, the upper portion of the medial brow ridges created two visible “bumps,” making the suprabrow break appear deeper than desired.
The surgical goal was a limited Type 1 forehead reduction: contouring the medial brow bone mounds to soften their appearance while preserving visible, masculine brow definition.
Surgical Technique
Under general anesthesia, a small incision was made just behind the frontal hairline. A special curved retractor provided access and visualization, allowing the surgeon to reduce the medial brow mounds by burring without exposing the frontal sinus. The incision was then closed, leaving only a minimal, well-hidden scar.
The immediate outcome was a smoother contour, with less prominent brow bone mounds and a shallower suprabrow break.
Discussion
Burring of the medial brow bone overlying the frontal sinus is an infrequently used technique. Its success depends on sufficient bone thickness in this region. For many men with significant brow projection, a more extensive Type 3 forehead reduction (bone flap setback) is required. This is why trans women almost always undergo Type 3 procedures for effective feminization.
However, for patients seeking only a modest softening—particularly men who want to maintain but slightly refine their brow definition—the burring method can be effective. Men often have thicker frontal sinus bone coverings, which makes this approach feasible. This technique is best viewed as brow bone reshaping rather than a full reduction.
Key Points
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Limited brow bone reduction can be achieved through burring with a small hairline incision.
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The extent of safe reduction depends on the cortical bone thickness over the frontal sinus.
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The incision must be placed near the frontal hairline for optimal access and visualization.
Dr. Barry Eppley
World-Renowned Plastic Surgeon