Can A Sliding Genioplasty Be Done For Moments Over 10mm or 12mms?
Q: Dr. Eppley, I have a few questions about your approach to genioplasty. I sent your assistant my picture and question about having genioplasty plus implant. She sent me your reply with a morphed picture, along with your assertion that a geneoplasty alone should be enough considering all I should need would be 12mm or so of advancement. I also posted a similar question about my chin with the same picture on Real Self, to which you also replied explaining a bit more about the geneoplasty plus implant procedure.
As far as I can tell, you are the only doctor offering genioplasty movements of above 12mm. Most surgeons consider 8-10mm the maximum, with a handful suggesting 12mm may be possible:
1. Why is there such a disparity between what the numbers of 14-16mm you have achieved, and the vast majority of surgeons which seem decidedly reluctant to perform such a large movement? Is there anything different about your specific method that others don’t perform? I understand the degree of possible projection being due the thickness of the bone.
2. When considering the addition of a chin implant to further augment the projection, what are the limits?: As I understand it from what I’ve read in your articles, there’s a limit to the amount the soft tissue can stretch horizontally in a single operation — how much projection can you achieve in one go with genioplasty + chin implant? Additionally, is there similarly a projection limit if you were to instead consider adding an implant once the genioplasty had healed? (For example, could you have a 15mm genioplasty and then 6 months later [or however long it takes to heal] add a large implant like the Terino Square Style Chin 1 at 11mm?)
Given your initial email response and then what I read as somewhat of a conflicting one on RealSelf, I’m unsure of what the recommendation would be for my case. I have attempted to measure my degree of deficiency with a ruler — angling a small ruler along my jawline and measuring from the base of my chin to just slightly behind my lower lip — and deduce from that that I would need a horizontal advancement of about 2.5cm: a figure widely off from your recommendation of around 12mm, so I presume my rudimentary attempts at measuring myself are inaccurate. I have attached my picture again below.
Many thanks for your time.
A: In answer to your sliding genioplasty questions:
1) I can only speak from my own sliding genioplasty experience and techniques. I suspect that most surgeons view how much forward movement is possible based on the need for extensive bone contact between the two chin segments. That may have merit if one is using non-bone grafting techniques. I learned long ago that all sliding genioplasties create an unnatural shape to the chin (step off) and making the effort to graft these created defects using tissue bank chips or block bone grafts is a useful technique. It is important to understand that the more the chin bone is moved forward the greater these bone defects will be and the more these types of bone grafts are needed.
2) When it comes to the need for very large chin movements, it is important to make the bone to most of the work in achieving it. These can take two basic approaches; 1) lessen the sliding genioplasty amount (10mms) and immediately place an implant overlay, or 2) maximum the chin bone movement forward (14 to 20mms) and plan a second stage implant overlay later if needed. (6 months or more) Whether this is using a standard or custom design chin implant remains to be determined. The key to an immediate or delayed chin implant overlay is that the implant can not exceed 1/3 in horizontal projection over what the bone movement has achieved due to the limits of soft tissue stretch.
Each patient’s case must be assessed by computer imaging to determine which approach is best and how much horizontal projection is really needed.
What I do know is that your description of adding an 11mm chin implant secondarily, regardless of the amount of chin bone movement, is neither possible nor advised.
Lastly I assume your ideal location of chin projection is the often quoted vertical line dropped down from the lips. I would question whether 25mms would be the correct number to achieve that but what I do know is the following and I will assume for the sale of discission that 25mms of projection is the goal:
1) A 25mm custom chin implant would never fit.
2) A 25mm sliding genioplasty is not possible either…both due to the limits of soft tissue chin pad stretch.
3) Therefore the best approach is maximum whatever the chin bone can be moved and then evaluate later whether any more projection is really needed. What usually fits after such efforts is probably a 5mm implant on the end of the bone placed through a submental approach. Custom implant design is best since the goals would be to widen the chin, cover over any residual step-offs and provide a square shape per your description.
Dr. Barry Eppley