biomaterials and implants

Question 1

what are the components of integra

Answer 1

bilayer wound matrix or single layer w/o silicone
semi-permeable silicone (mimics epidermis)
cross linked bovine tendon collagen GAGS (dermal)

Question 2

what are the components of apligraf

Answer 2

living bilayer skin sub
dermal = bovine type 1 collagen + human fibroblasts
epidermis = human keratinocytes
cells from neonatal foreskin

Question 3

Bone subs

Answer 3

demineralized bone matrix
coral
hydroxyapatite
calcium sulfate
calcium phosphate/tricalcium phosphate

Question 4

what are the basis of alloderm, flex HD, allomax?

Answer 4

human

Question 5

what are is the source for strattice, permacol?

Answer 5

porcine

Question 6

what is the source of veritas, surgimend?

Answer 6

bovine

Question 7

what side of alloderm is placed towards vasculature?

Answer 7

shiny

must be used within 4hrs of rehydration

Question 8

what revascularizes faster cancellous bone or cortical bone?

Answer 8

cancellous bone

cortical bone is structural

Question 9

what is endochondral ossification?

Answer 9

bone formed from hyaline cartilage model that becomes partially ossified
- retains cartilaginous portion as articular cartilage and epiphyseal growth plate

Question 10

what is osteoconduction?

Answer 10

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)

Question 11

what is osteoinduction

Answer 11

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

Question 12

how is cartilage warping/shaping minimized?

Answer 12

symmetric carving

Question 13

what collagen substitute requires skin testing 4 weeks prior to use?

Answer 13

zyderm/zyplast
bovine

Question 14

what is the source of collagen substitute cosmoderm/cosmoplast

Answer 14

human

Question 15

what is the source of collagen substitute evolence?

Answer 15

porcine

Question 16

what are the components of hyluronic acid

Answer 16

d-glucuronic acid and N-acetyl-glucosamine

repeating disaccharide

restylane/perlane
juvederm
belotero
prevelle silk
hydrelle
captique
hylaform

Question 17

what is radiesse

Answer 17

calcium hydroxylapatite 30% in cellulose gel

Question 18

what is the common component in resorbable sutures and plates

Answer 18

polylactic acid

degraded by hydrolysis into lactate
lasts for 2-5yrs

Question 19

what is sculptra made of

Answer 19

poly-L-lactic acid

Question 20

what is polymethylmethacrylate used in?

Answer 20

bone cement

stimulates host collagen deposition

Question 21

what is artefill made of

Answer 21

bovine collagen and PMMA microscpheres

skin test required for anything bovine collagen

PMMA is permanent

Question 22

what is the estimated resorption of fat at 12 months

Answer 22

50%

70% at 3 months

Question 23

what is autologen?

Answer 23

autologous skin harvest

Question 24

what is isolagen

Answer 24

cultured punch biopsies

Question 25

what is dermalogen

Answer 25

cadaveric tissue

Question 26

what is fascian

Answer 26

preserved particulate fascia (cadaveric)

Question 27

what is the 10 yr reoperation risk of saline implants?

Answer 27

25%

Question 28

when is the silicone layer of integra removed?

Answer 28

21 days (minimum may be better to wait full 4 weeks) after the GAG layer is fully revascularized

Question 29

what increases the longevity of saline implants?

Answer 29

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

Question 30

what characteristic of hyaluronic dermal fillers is responsible for prolonging results

Answer 30

cross-linking

Question 31

does cartilage graft vs bone graft have less or greater resorption

Answer 31

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

Question 32

what is the advantage of using integra with STSG rather than just skin graft alone

Answer 32

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

Question 33

does hydroxyapatite bone cement allow for peripheral ingrowth of bone

Answer 33

yes it is osteoconductive no risk of endothermic rxn (seen with methylmethacrylate cement) does not lose contour over time