One of the most common of all aesthetic raised skull deformities is that of the sagittal ridge. As a result of the fusion of the midline sagittal suture, bone thickening can occur between the original anterior and posterior fontanelles. In its fullest expression such sagittal suture fusion becomes a craniosynostosis. But there are numerous smaller or incomplete versions of craniosynostosis where only a raised ridge of bone occurs down the middle of the skull without causing a lengthening of the skull from front to back or any significant transverse narrowing.
The sagittal ridge or crest creates a prominence that is particularly visible in men with short hair or who shave their head. It makes the top of the head appear as an inverted V as opposed to a more smooth convex shape. Only in animals is the presence of a sagittal ridge normal which is due to the attachment of the strong masseter muscles. The tenporalis muscle in humans is attached far more to the sides of the skull which allows it to have a more recognizable smooth convex shape.
The reduction of the sagittal ridge can be effectively done through a burring technique. One key is to keep as small an incision as possible which is located at the back portion of the ridge. While the back portion of the ridge is fairly easy to reduce, the portion of the crest that extends forward is more challenging. The second key is to have long narrow retractors which allows a handpiece and shaping burrs to be inserted to complete the reduction. Any residual high bony areas located way far forward can be reduced with large diamond rasps.
An important question to answer before this type of skull reshaping surgery is how thick is the sagittal ridge and how much can it be reduced. This can be quantitatively determined before surgery with a 3D CT scan where the bone thickness can be measured if there isn any doubt as to its thickness. When burring down the ridge it is common, particularly in the back, to encounter large bone bleeders and these are effectively obliterated with bone wax. When the color of the midline bone starts to become a faint blue in color, it is time to stop as the inner cortex is getting thin. Usually up to 7mms of crestal bone can be reduced.
Dr. Barry Eppley
Indianapolis, Indiana