A type 3 forehead reduction (also referred to as a type 3 brow bone reduction or type 3 cranioplasty) is performed for people with excessive brow bossing who wish to undergo brow bone reduction surgery. This type of Brow Bone Reduction Surgery is commonly performed for transgender women, however it is also done for cisgender women and cisgender men who are dissatisfied with the appearance of their forehead. This is one of the few surgical procedures that are commonly used for Forehead Feminization as part of more general Facial Feminization Surgery.

The term “type 3” comes from the original research performed by Dr. Douglas Ousterhout.¹ In his original research on the topic, he noticed there were three types of foreheads he encountered when performing modifications of frontal bossing with surgery. A type 1 forehead was one where the brow bossing can be addressed with burring alone. A type 2 forehead was one where the brow bossing was addressed by burring the bone low on the forehead and using the addition of an artificial material higher on the forehead to improve the transition. A type 3 forehead was one where the brow bossing needed to be addressed by making cuts in the bone and repositioning that bone. Type 3 brow bone reduction refers to this procedure.

Contouring the forehead can rarely involve simply burring the bone in that region. More commonly, cuts need to be made into the frontal sinus in order to move the bone backwards. If one were to simply shave down the bone at the forehead, holes would be produced into the frontal sinus and a large setback would be unobtainable.

These illustrations demonstrate the desired effect on a skull from reduction of forehead bossing. Notice the prominent frontal bone bossing above the root of the nose.

When there is a large frontal sinus, it can be necessary to make cuts into the frontal sinus in order to move the outer surface of the bone. This is more easily explained using a cross-section of the skull. The image below demonstrates a cross-sectional view down the center of the face. It shows brow bossing from a profile (sagittal) view. In this view, the frontal sinus is shown in black. It is bordered by bone on the front (anterior) and back (posterior) sides.

When there is a large frontal sinus, it can be necessary to make In order to reposition the outer piece of bone (the anterior table of the frontal sinus), cuts need to be made around the edges of the frontal sinus.

This allows the front part of bone to be removed and contoured to the appropriate forehead shape. After removing the bone from the patient, the piece is contoured to create a round forehead.

The anterior table of the frontal sinus is then replaced at a position behind (posterior to) to its original position. In this position, the brow bossing is removed and a more feminine facial profile is obtained.

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