Custom skull implants provide an unparalleled ability to reshape the head when an augmentative effect is needed. Whether the implant augmentation is completely on bone or involves resting on the soft tissues on the side of the head, the ability of the implant to produce a smooth contour that blends into the surrounding skull surface’s is one of its key design features.
Another one of what a custom skull implant does and always needs to do is to have a footprint (perimeter of the implant) that is large enough to create a smooth and natural contour to the implant. It is this very necessary design feature that also can pose challenges for implant placement. With skull implants that cover large surface areas getting the implant in through relatively small scalp incisions can be a challenge. The elastic deformation property of solid silicone skull implants can help reduce an implant’s diameter so that it can fit through a scalp incision that is less than 50% of the implant’s base diameter. But this does not always work the larger the diameter and surface area coverage that the implant has.
In these cases, rather then exceed the scalp incision, a split implant placement technique is used. This is where the implant is sectioned into two pieces and then reassembled back together once both implant pieces are inside the pocket past the incisional entrance. In most large skull implant cases the split line will be from side to side rather than along its length. This keeps the scalp incision remarkably small when compared to the implant’s size.
Once both pieces of the implant are on the skull’s surface and brought back together, and the implant is in proper position, it is secured on both sides of the split line with small screws (more like tacks) that only penetrate into the bone 1 to 2mms. The scalp incision is then closed in two layers with resorbable sutures.
While custom designing of skull implants offers endless options in terms of sizes and shapes it is also important when doing a design think of how it will be placed. While all custom skull implants can be most easily placed through long coronal scalp incisions that is not an aesthetic tradeoff that most patients are willing to accept. The split placement technique allows some of the scar burden to be lessened and allows the placement of skull implants to be done through much small scalp incisions than thought possible.
Dr. Barry Eppley
World Renowned Plastic Surgeon