biomaterials and implants Flashcards
what are the components of integra
bilayer wound matrix or single layer w/o silicone
semi-permeable silicone (mimics epidermis)
cross linked bovine tendon collagen GAGS (dermal)
what are the components of apligraf
living bilayer skin sub
dermal = bovine type 1 collagen + human fibroblasts
epidermis = human keratinocytes
cells from neonatal foreskin
Bone subs
demineralized bone matrix
coral
hydroxyapatite
calcium sulfate
calcium phosphate/tricalcium phosphate
what are the basis of alloderm, flex HD, allomax?
human
what are is the source for strattice, permacol?
porcine
what is the source of veritas, surgimend?
bovine
what side of alloderm is placed towards vasculature?
shiny
must be used within 4hrs of rehydration
what revascularizes faster cancellous bone or cortical bone?
cancellous bone
cortical bone is structural
what is endochondral ossification?
bone formed from hyaline cartilage model that becomes partially ossified
- retains cartilaginous portion as articular cartilage and epiphyseal growth plate
what is osteoconduction?
cortical bone graft functions as nonviable scaffold for gradual ingrowth of blood vessels nd osteoprogenitor cells from recipient site
gradual resorption and deposition of new bone (creeping sub)
what is osteoinduction
transformation of local host mesenchymal cells into bone forming cells in prescence of inductive stimulus (BMP)
regulated by insoluble polypeptide morphogens BMP
requires demineralization prior to implantation
how is cartilage warping/shaping minimized?
symmetric carving
what collagen substitute requires skin testing 4 weeks prior to use?
zyderm/zyplast
bovine
what is the source of collagen substitute cosmoderm/cosmoplast
human
what is the source of collagen substitute evolence?
porcine
what are the components of hyluronic acid
d-glucuronic acid and N-acetyl-glucosamine
repeating disaccharide
restylane/perlane
juvederm
belotero
prevelle silk
hydrelle
captique
hylaform
what is radiesse
calcium hydroxylapatite 30% in cellulose gel
what is the common component in resorbable sutures and plates
polylactic acid
degraded by hydrolysis into lactate
lasts for 2-5yrs
what is sculptra made of
poly-L-lactic acid
what is polymethylmethacrylate used in?
bone cement
stimulates host collagen deposition
what is artefill made of
bovine collagen and PMMA microscpheres
skin test required for anything bovine collagen
PMMA is permanent
what is the estimated resorption of fat at 12 months
50%
70% at 3 months
what is autologen?
autologous skin harvest
what is isolagen
cultured punch biopsies
what is dermalogen
cadaveric tissue
what is fascian
preserved particulate fascia (cadaveric)
what is the 10 yr reoperation risk of saline implants?
25%
when is the silicone layer of integra removed?
21 days (minimum may be better to wait full 4 weeks)
after the GAG layer is fully revascularized
what increases the longevity of saline implants?
as volume increases palpable and visible wrinkling decreases
underfilled implants have also shown to wrinkle more leading to shorter lifespan because of the stress induced by wrinkling
what characteristic of hyaluronic dermal fillers is responsible for prolonging results
cross-linking
does cartilage graft vs bone graft have less or greater resorption
cartilage have less resorption and volume loss
1/100-1/500 metabolic rate compared with other human tissues
low gylcolytic activity and consumption because of its small cell population and relative isolate by the cartilage matric
what is the advantage of using integra with STSG rather than just skin graft alone
reliability of placement technique, pliability, and final cosmetic appearance
allows for thinner graft so less risk of overall scarring, infection and pigmentation changes
less wound contraction
longer healing time due to it being a staged procedure
does hydroxyapatite bone cement allow for peripheral ingrowth of bone
yes it is osteoconductive
no risk of endothermic rxn (seen with methylmethacrylate cement)
does not lose contour over time
