The kind of plastic surgery procedure as well as the size and character from the defect being corrected often dictate the kind of implant material. In the preantibiotic era, inert materials for example gold, silver, platinum and paraffin were used with little success and were quickly abandoned. Currently, there are numerous implantable materials being used toda. These materials are used in an array of procedures, such as aesthetic procedures, craniofacial surgery, maxillofacial trauma, breast reconstruction and hand surgery.
Silicone-based prosthetics happen to be used as medical implants because the 1950s because of their chemically inert nature, resistance to degradation, and insufficient significant allergy symptoms. Silicone is advantageous for a variety of aesthetic surgeries, complex contouring and reconstructive procedures. Silicone comes in the type of silicone gels, silicone rubber or solid silicone implants. Silicone gels can offer a more natural feel, as seen with breast implants, but the risk of rupture requiring capsulectomy is really a distinct disadvantage.
The use of silicone gel has been encompassed by controversy associated with concerns about migration, toxicity and an unproven association with systemic disease, resulting in restriction from the utilization of silicone gel implants by the FDA in 1992. This ban was recently lifted after a comprehensive unbiased review by the Institutes of drugs. Silicone rubber can be used for tissue expanders, the outer shell of both saline-filled and silicone gel-filled breast implants, so that as an onlay material for the augmentation from the bony skeleton and soft tissues.
However, silicone rubbers are relatively weak and often tear, leading to implant failure. Solid silicone implants are commonly used for chin and malar augmentation, and have been used in nasal, chest and calf augmentation, as well as in joint replacement and tendon reconstruction.
Because silicone isn't porous, tissue ingrowth does not occur. A fibrous capsule forms around the implant that is relatively avascular and can contract which might result in implant migration. This avascular capsule is a potential space for infection and in the setting of infection may need elimination of the implant.
BioPlastique is really a nonbiodegradable, relatively inert injectable liquid employed for soft tissue augmentation. The textured surface of the particles enables tissue ingrowth, and the particle dimensions are big enough to avoid engulfment by macrophages but small enough being encapsulated within 3 to 6 weeks.
Studies on the use of BioPlastique demonstrate good-to-excellent results in augmenting small defects on the dorsal nose, malar area, cheeks and chin with no adverse immunologic reactions. Although the clinical results with Bioplastique happen to be encouraging, it's not FDA approved at the moment.
Polymethylmethacrylate (PMMA) is definitely an acrylic polymer used like a bone substitute in plastic surgery and neurosurgery. PMMA is radiolucent, extremely durable and completely biocompatible, which makes it a popular material for cranial bone reconstruction-alone or in combination with wire or mesh reinforcement.
When powdered granules of methylmethacrylate polymer are mixed with methylmethacrylate liquid monomer, a moldable dough forms as the monomer polymerizes and hardens in about 10 mins. Close to the end of the polymerization process, an exothermic reaction occurs that could possibly damage the local tissues, the major complication linked to the utilization of PMMA. This is often avoided by continually irrigating the implant bed with cool saline during the polymerization.
An uncommon, but serious complication may be the inadvertent entry of the PMMA to the venous or arterial systems. If this occurs it may cause complete heart block, cardiac arrest and other arrhythmias. This complication is frequently seen during orthopedic procedures where PMMA is used for joint replacements or fracture repair.
Hard-tissue-replacement (HTR) polymer is a porous type of PMMA that allows for fibrous ingrowth, resulting in an implant that is nonresorbable and incredibly stable. Applications for HTR include chin and malar augmentation, with potential for additional uses in craniofacial reconstruction.
Polyethylene terephthalate (Dacron) is a biocompatible, flexible, nonabsorbable polymer that can be used as a suture material, like a prosthetic material for arterial replacement, so that as a mesh (Mersilene) in abdominal and chest wall reconstruction. Its use has additionally been described for chin and nasal augmentation.
Polyglycolic acid (PGA) and Poly(L-lactide) (PLLA) are polymers that are degraded in the body at physiologic pH during the period of weeks to months. These resorbable polymers are available as mesh sheets for body wall reconstruction and as rods for the internal fixation of fractures and osteotomies. They have been fashioned into resorbable miniplates and screws for the fixation of bones from the craniofacial skeleton. Although they don't appear to have any cytotoxic effects, they are doing provoke an inflammatory or foreign body response after implantation.
Polyamide mesh is a woven, polymer mesh implant that is biocompatible, can be easily shaped and sutured, enables fibrous tissue ingrowth, and it has been used for the repair of orbital floor defects. It appears to become well tolerated and it has a low rate of extrusion, even in regions of thin skin like the nasal dorsum. However, polyamides do undergo resorption and induce an inflammatory response, making their use in facial augmentation and reconstruction somewhat limited.
Medpor is really a high-density, porous polyethylene implant used frequently in facial surgery since it is nonantigenic, nonallergenic, nonresorbable, highly stable and simple to fixate. In addition, Medpor can be obtained in a multitude of preformed shapes for its use as a malar, chin, nasal, orbital rim, orbital floor and cranial implant, as well being an auricular framework in postburn ear reconstruction. Overall, complications of Medpor, such as exposure or infection, are rare.
Polytetrafluoroethylene (PTFE) is definitely an inert and highly biocompatible polymer that is extremely useful in soft tissue augmentation but has limited use in bony repair because of its low tensile and compressive strength. Teflon, the first PTFE graft to be used in plastic surgery, is really a chemically inert polymer employed for soft tissue augmentation in the past, but the main application for Teflon continues to be orbital floor reconstruction.
Gore-Tex is really a pliable, durable, inert, biocompatible material that has some tissue ingrowth, little inflammatory reaction and almost no encapsulation. In addition to being used in abdominal fascial reconstruction, chest wall reconstruction and soft tissue reconstruction, Gore-Tex has additionally been utilized for lip, nasal, chin and malar augmentation. It has been utilized for the treatment of nasolabial and glabellar creases.
Proplast I is a highly porous, black graphite/PTFE composite having a spongy consistency. Because Proplast I resulted in discoloration from the surrounding soft tissues when implanted, Proplast II-a more rigid, white PTFE/alumina compound-was developed as an alternative.
Proplast, with a wide variety of applications including the reconstruction of the chin, zygoma, orbital rim, maxilla, mandible, skull and rib cage, was originally regarded favorably. However, reports of biomechanical failure, intense inflammation, infection and extrusion associated with the Proplast temporomandibular joint implant, led to removing all Proplast implants from American markets through the FDA in 1990.
Calcium phosphate implants happen to be available as bone replacement/augmentation materials for 25 years. The main calcium phosphates in clinical use are hydroxyapatite and tricalcium phosphate. These materials are osteoconductive (providing a scaffold for bone ingrowth) thus permitting integration into the recipient site after placement. As a result, calcium phosphates are extremely well tolerated with essentially no inflammatory response, minimal fibrous encapsulation, and no adverse effects on local bone mineralization.
Metals have been employed for the past 35 years for skull reconstruction and repair, in addition to reconstruction of craniofacial and upper extremity skeletal injuries. Stainless, cobalt-chromium (vitallium), pure titanium and titanium alloys are the principal metals currently available. Characteristics of the desirable metal implant include biocompatibility, strength, potential to deal with corrosion and imaging transparency.
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