The different materials available for standard and custom facial implants are well known and include silicone, Medpor, Goretex and PEEK in the U.S.. The first three are available in standard facial implants and silicone, Medpor and PEEK are available in custom facial implants. There are numerous differences between all of these implant materials and the reality is that no one of them is perfect. Each biomaterial has their advantages and disadvantages and knowledge of their material properties is key in determining which one is ideal for any particular patient.
One of the most interesting and often discussed features of these biomaterials is tissue ingrowth or adherence which is most manifest in the Medpor (polyethylene) material. This material gets the most robust tissue ingrowth which occurs due its surface porosity. This is a material advantage until it becomes necessary to revise or remove the implant. Such removals are well known to be difficult and according to some surgeons even impossible.
Having removed hundreds of Medpor facial implants I can provide some perspective on what this entails. First it is absolutely true that they are not easy to remove…but this should not be considered impossible. When contrasted to a silicone implant, which has no tissue adherence, Medpor implant removal can certainly seem incredibly arduous. But with deliberate technique and starting with separation first from its underside from its attachment to the bone (where no bony ingrowth has ever been seen) they can be successfully removed.
Where Medpor implant removal becomes the most difficult is in the jawline area due to the proximity of nerves and blood vessels. Because of its robust tissue attachments there is definitely a risk of injury to the sensory mental nerve at the upper end of the chin implant area and the motor marginal mandibular nerve where it crosses at the inferior end of the lateral chin area. These are significant concerns and such injuries of they occur may be more severe than merely a stretch type trauma which can occur from implant placement.
But the most ‘dangerous’ structure at risk is the facial artery in Medpor jaw angle implant removal. This branch off of the external carotid artery crosses just above the periosteum at the anterior end of the antegonial notch along the jawline. This is exactly where the front end of a jaw angle implant would be and dissecting the very adherent tissue off of the implant places the artery at risk of being torn. I have seen it occur more than once and, while not life threatening, it can be very difficult to get under control and one can easily lose a unit or two of blood in doing so.
Medpor facial implants can be removed, often requiring them to be removed in multiple pieces. The dissection needed for their removal is tedious and it takes time to do so. Patients show know that the proximity neves and vessels may be at risk in their removal. Vascular compromise can be controlled without any postoperative sequelae. Nerve injuries due to detaching the implant from the nerve or tissue immediately around it can result in lingering effects.
Dr. Barry Eppley