Implant (medicine)
The surface of implants that contact the body might be made of a biomedical material such as titanium, silicone, or apatite depending on what is the most functional.
[1] In 2018, for example, American Elements developed a nickel alloy powder for 3D printing robust, long-lasting, and biocompatible medical implants.
Examples include the intraocular lens, intrastromal corneal ring segment, cochlear implant, tympanostomy tube, and neurostimulator.
[1][3][4] Cardiovascular medical devices are implanted in cases where the heart, its valves, and the rest of the circulatory system is in disorder.
[5] They are used to treat bone fractures, osteoarthritis, scoliosis, spinal stenosis, and chronic pain as well as in knee and hip replacements.
Examples include a wide variety of pins, rods, screws, and plates used to anchor fractured bones while they heal.
[6][7] Patients with orthopaedic implants sometimes need to be put under magnetic resonance imaging (MRI) machine for detailed musculoskeletal study.
[13] Contraceptive implants are primarily used to prevent unintended pregnancy and treat conditions such as non-pathological forms of menorrhagia.
[3][4][14] Cosmetic implants — often prosthetics — attempt to bring some portion of the body back to an acceptable aesthetic norm.
Implants are used in those and other locations to treat conditions such as gastroesophageal reflux disease, gastroparesis, respiratory failure, sleep apnea, urinary and fecal incontinence, and erectile dysfunction.
Class III devices include replacement heart valves and implanted cerebellar stimulators.
The thickness of this layer is determined by the products being dissolved, and the extent to which the implant moves around within the enclosing tissue.
[24] The reduction in the modulus of the implant follows a complex nonlinear relationship dependent on the volume fraction of base material and morphology of the pores.
Different models, such as the rule of mixtures for low porosity, two-material matrices have been developed to describe mechanical properties.
[28] AM has the ability to fine-tune the lattice spacing to within a much smaller range than stochastically porous structures, enabling the future cell-development of specific cultures in tissue engineering.
[24] Bone ingrowth is a favorable effect, as it anchors the cells into the implant, increasing the strength of the bone-implant interface.
Other complications that can occur include risk of rejection from implant-induced coagulation and allergic foreign body response.
Depending on the type of material used to make the implant, it may be infused with antibiotics to lower the risk of infections during surgery.
When this occurs, the protein changes conformation and different activation sites become exposed, which may trigger an immune system response where the body attempts to attack the implant to remove the foreign material.
The immune system response may lead to chronic inflammation where the implant is rejected and has to be removed from the body.
Lastly, the immune system may accept the presence of the implant and repair and remodel the surrounding tissue.
In United Kingdom, Prof Derek Alderson, president of the Royal College of Surgeons, concludes: "All implantable devices should be registered and tracked to monitor efficacy and patient safety in the long-term.
