Background: The effect of any chin implant is a function of its shape, size and position on the bone. Either one can be a cause of ‘macrogenia’, the perception that the projection of the chin is excessive. The most frequent treatment for an implant-induced macrogenia is to simply replace it which is what is almost always done with a silicone chin implant because of its ease of removal.
In Medpor chin implants there is always the consideration of rather than trying to remove it to reduce it while it is in place. Due to its tissue ingrowth and an increased difficulty with its removal, there is always the consideration of modifying the implant in place. This can be a good strategy based on what dimension needs to be reduced. There is a certain limitation as to how much of the implant can be accessed for removal as well as the safety of doing so. (tissue stretch and potential for nerve injury of either the mental but more pertinently the marginal mandibles branch of the facial nerve)
Case Study: This male had a prior history of a Medpor chin implant that resulted in a oversized appearance. He felt it made his face longer and too wide. On palpation the lower edge of the implant could be felt hanging below his chin bone.
Under general anesthesia and through his existing submental skin incision the split in the Medpor chin implant was identified and the soft tissues elevated from the outer surface of the implant. A reciprocating saw was used to cut off the part of the implant that was below the level of the bone which was a 6mm length.
The sides of the implant was then trimmed down using a scalpel.
When seen more than one year later the effects of the in situ chin reduction could be seen.
As a general rule it is rarely ideal to modify a chin implant in place. Often the limited access and ability to accurately reduce the implant compromises the aesthetic result. One have to be fairly proficient in working with implant materials to do so. But if the dimensions of the implant that need to be changed are clearly understood and easily accessible through the submental incision successful results can be achieved.
1) A chin implant that is too big or malpositioned can be a reason for an ‘implant-based’ chin reduction.
2) A Medpor chin implant can be reduced in place in some cases depending on what dimensions of it need to be changed.
3) The submental approach provides the method to modify/reduce a Medpor chin implant in place.
Dr. Barry Eppley