The size of one’s head is most significantly influenced by the shape of the skull. While there are soft tissues that also envelope it, its size is a reflection of its overall dimensions and convexity. As a result, major reductions (1 cm or greater) in skull size or specific bony areas is not possible without creating a full-thickness bone defect.
But despite these bone thickness limitations, this does not mean that meaningful reduction in the skull can not be done. The skull has three layers very much like an Oreo cookie, an inner and outer cortical layer and a much thinner middle diploid space (marrow) layer. This can clearly be seen in standard skull x-rays. It is the outer layer of the skull that can be reduced or roughly up to one-third of the skull’s thickness can be removed.
Outer table skull reduction is done by a bone burring technique. A high speed handpick with a fluted carbide burr can efficiently remove the outer table bone and transform it into bone dust. Over larger skull areas an effective approach is to create a grid pattern across the curved skull surface. By creating these 2 x 2 cm square islands of bone, it allows the proper depth to be placed just on the outer aspect of the diploid space and also ensures a more even level of bone removal. It is easy when reducing large skull surfaces to not be completely even at the depth of bone removal. So it is helpful to check oneself at regular intervals with smaller sections of bone reduction.
Because skull reduction is done right down to the diploid space, there is going to be some blood oozing from the bone (what I call ‘bone sweat’) right after surgery. For this reason the use of small drains for a day or to after surgery is needed to prevent any buildup of blood under the periosteum of the scalp. It also helps with lessening the amount of swelling and/or bruising that might find its ways down onto the face after surgery.
Dr. Barry Eppley