Background: The desire for aesthetic skull augmentation can be for multiple skull shape concerns. In females one of the most common is for an increased crown of the head height. There is often a predicate history of hairstyle methods to increase the appearance of the crown of head height, which can be successful, but involves a lot of work/time on a daily basis and adds up over the years. There are even non-surgical devices to create it (Bumpit) which has its limitations.
A custom skull implant provides the definitive solution for crown of the head augmentation but its success depends on having enough implant volume (size) to do so. The implant volume needed depends on how much crown height is needed from ‘just a little’ to ‘a lot’. Those verbal descriptions have to be translated into a visual understanding which is done by computer imaging (Photoshop) of potential crown of head augmentations done in profile.
But besides the imaged change in crown of head height a judgement is also required of how much the patient’s scalp can stretch to safely accommodate the implant size. In thinner scalps with larger implant volumes a first stage scalp expansion is needed.
Case Study: This Caucasian female desired significant skull augmentation with the major effect at the crown of her head. Given her scalp thickness with limited flexibility and the size of the skull implant needed to achieve her goals a first stage scalp expansion was needed. The scalp expander was placed through a posterior scalp incision done in the prone surgical position.
While the scalp expansion were ongoing at home done by the patient through serial injections of 10cc every 2 to 3 days, a custom skull implant was designed with 200ccs of volume and 15mm of maximal projection. The patient filled the scalp expander to 200cc of saline volume to match that of the implant design.
In the second stage surgery 3 months later the scalp expander was removed through the original incision.
The two piece skull implant could be seen prior to placement in how it would fit together once inside the expanded scalp pocket.
In comparing the skull implant to the expander it is important to appreciate the shape differences. The scalp expander is round with dome shape while the skull implant is oblong being taller more to the back than the front.
The skull implant was placed in two separate pieces and then put together using the geometric split line. This is always challenging since putting the implant together is largely done in a blind fashion. (Not seeing most of the implant) Once put together it was centered and the split secured by sutures and micro screws.
The scalp incision was closed in two layers with resorbable sutures over a drain.
The sequence in head shape differences can be seen in surgery in the prone position before the scalp expander placement, after scalp expansion and with the custom skull implant in place.
All custom skull implants to be successful (surgical placement and postoperative tissue tolerance) require stretch of the scalp over it. If the scalp stretch is inadequate postoperative complications such as wound dehiscence, shock hair loss and infection can occur due to diminished blood flow into the overlying scalp.
Judging the stretch of the scalp is not an exact science nor is knowing how much implant volume that can be tolerated. But a lot of experience has taught me that how much the scalp can stretch is a function of its thickness which varies considerably based on gender, skin pigmentation and hair color. As a general rule thin Caucasian females with blonde or light brown hair have very thin scalps with limited stretch capability. Unless only a very small implant volume is needed (under 100ccs) these patients require a first stage scalp expansion which completely avoids all the aforementioned potential complications.
Key Points:
1) Larger skull implants in thin female scalps with little flexibility require a first stage scalp expansion.
2) A first stage scalp expansion volume should equal rot be greater than that of the custom skull implant design.
3) To keep the scalp incision limited large custom skull implants are designed in split pieces to be inserted separately and reassembled once inside the implant pocket.
Dr. Barry Eppley
World-Renowned Plastic Surgeon