Custom Occipital Skull Implant for Plagiocephaly

Q: Dr. Eppley, I’m a 24 year old male and, due to an untreated positional plagiocephaly in early infancy, the right posterior part of my skull is flattened showing the typical pattern of occipital postural plagiocephaly with an asymmetry of 6 mm between the two cranial vault diagonals. Since I got my hair shaved because of the incipient baldness, this flattening is more obvious.Thanks to the complete and invaluable information you provide on your website I think I have found a solution for my problem, a custom occipital skull implant, but I have doubts due to the particularities of my case.
The flattened area extends on the right side (viewed from the back), partially over the occipital and parietal bones, and slightly over the more posterior portion of the temporal bone. On the occipital zone, this causes a depression in the area surrounding the superior nuchal line where the occipitalis, trapezius, semispinalis capitis, splenius capitis and sternocleidomastoid muscles are attached. This is the area my question is about.
I understand that in cases of prominent nuchal ridge reduction these muscles of the superior nuchal line are detached for burring the nuchal ridge. I have also seen in the Web this kind of detachment in cases of anterior and lateral foramen magnum meningiomas surgeries where an extreme-lateral transcondylar and retrocondylar approaches respectively are performed, as well as in mastoidectomies.
My questions are:
1. The area corresponding to the attachment of the superior nuchal line muscles (the area delimited by the red line in the images) can also be augmented through a 3D custom-made silicone implant, or is there a maximum occipital inferior border to place the lower edge of the implant?
2. In which layer would the implant be placed? It will be directly placed on the skull bone and below the periosteum?
3. If the placement is subperiosteal and the nuchal ridge muscles are detached, how do the muscles are reattached to the skull if there is a piece of silicone underneath where they should be reattached? Does it have anything to do with the access being subperiosteal and lifting all the layers above the cranium like a flap?
4. Would detaching and reattaching the muscles cause muscle atrophy and, therefore, a reduction in its volume? If so, how can this unwanted effect can be camouflaged? Can detachment/reattachment affect the functionality of these muscles?
5. Can the implant be extended in one-single piece from the area of the upper nuchal line up towards the parietal bone?
6. Will the implant be fix to the bone with titanium screws?
7. Where will the incision be located in order to access the affected area?
8. The fact there is so little offer for cosmetic skull reshaping procedures around the world has something to do with the complexity of the procedure (technique, 3D custom implant supply,…), the lack of knowledge by the plastic surgeon about the existence of this procedure, the need for training as a craniofacial surgeon or maybe it is the little demand for this kind of cosmetic “job” (even when there is an increasing rate of people affected by plagiocephaly because of the “Back to sleep” campaign)?
Thank you very much in advance for your response.

A: Thank you for your inquiry and providing your specific skull shape concerns. Having done hundreds of skull implants of which the back of the head makes up half of them (of which those half are done for plagiocephaly), I can provide you the following answers to your occipital implant questions:

1) Augmentation of the occipital skull is NOT going to be done below the superior nuchal line. The contour below that line comes from the muscle not the bone and any detaching the muscle to have an implant extend below that line is counterproductive.

2) All skull implants are placed in the subperiosteal layer directly against the bone.

3) Once neck muscles are detached, they do not reattach nor can they be reattached regardless of whether there is an implant there or not.

4) Since the neck muscle can not be reattached and will cause some slight volume loss if so done, they should not be detached in any significant way. Hence why augmentation is not done below the superior nuchal line.

5) A custom skull implant can be designed to easily cover any contiguous skull area.

6) Most custom skull implants are secured with titanium microscrews.

7) A horizontal scalp incision, usually in the range of 7cm to 9 cms, is placed at the location of the nuchal judge in the hairline.

8) This does not appear to be a question but a statement for which I have no answer.

Dr. Barry Eppley
Indianapolis, Indiana