implants and biomaterials

8/19/2019 Implants and Biomaterials

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Implants andBiomaterials

Dr. Rashid Khan TMO

Plastic and Reconstructive SurgeryDate: 26/11/2 1!


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De"nition• The #ational $nstitutes o% &ealth de"nes a 'io(aterial

as:“any substance (other than a drug) or combination of substances syntheticor natural in origin, which can be used for any period of time, as a whole or part of a system which treats, augments, or replacestissue, organ, or function of the body.”

• )any (aterial used in a (edical deviceintended to interact *ith 'iologicalsyste(s+,


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&istorical Pers-ective

• io(aterials are 'eing used 'y hu(anaround 2 years in the %or( )sutures,

• Modern i(-lants date 'ac0 to 1 s+ *hen

ritish o-thal(ologist unintentionally usedcano-y -lastic in S-it"re -ilots3 eyes in4uriesleading to its use in cataract surgery asintraocular i(-lants in 1 .

• $n 1 ! s 5u('erland and Scales descri'ed)-ro-erties o% an ideal i(-lant,


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5lassi"cation

io(aterials (ay 'e classi"edaccording to:1. Source

– Synthetic + 'iological

2. Composition – Metals+ -oly(ers+ cera(ics+ adhesives

glues+ s0in su'stitutes

3. Host tissue responses – ioinert+ 'ioactive 'ioresor'a'le


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Re7uisites o% ideal i(-lant

• Sha-e• Sur%ace• 8a-

• Margins• Positioning

• Su-ra-eriosteal• Su'-eriosteal

• $((o'ili9ation• Suture• Scre* " ation


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io(aterials co(-osition

• Metals• Poly(ers

• 5era(ics• ;dhesives and glues• S0in su'stitutes

• io-rosthetic (esh


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Metals

Stainless steel:• $ron


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Metals

5o'alt< 5hro(iu(:• Fitalliu( >5o


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Metals

Titaniu(:• $ntroduced in (edical a--lications in 1 G• Re-laced al(ost all other alloys

• Stronger+ lighter+ less corrosive and less irritant• =ess stress shielding due to less stiHness• Mini(al arti%act on 5T / MR$• 5an %or( 'onds *ith surrounding 'one *ithout

ty-ical "'rous tissue %or(ation hence ideal %orosteointegrated i(-lants• Plates and scre*s %or rigid " ation and (esh

%or or'it/s0ull reconstruction


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Metals

8old:• 5he(ically inert 'ut -oor (echanical

-ro-erties

• Iyelid *eight in lago-thal(os


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Metals

Platinu(:• $nert li0e gold 'ut denser thus ideal eyelid

i(-lant in lago-thal(os in -atients *ith

gold sensitivity• =o* -ro"le and hence less noticea'le• So(e %or(ulation (ay 'e i((unogenic• sed as catalyst in (anu%acture o% silicon

gel i(-lant• 5is-latin+ -latinu( che(othera-eutic agent


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Poly(ers

• Poly(ers are (olecules o% re-eatingsu'units

• ac0'one series o% (oleculescovalently 'onded to side chains

• Physical -ro-erties de-ends u-on thestructure+ nu('er and cross lin0ingo% (ono(ers

• I ist in li7uid+ gel and solid %or(


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Poly(ers

Silicone:• Eirst introduced in S in 1 6• Most (aligned and (isunderstood 'io(aterial

• 5onsists o% alternating Si and O 2 (olecules• Silo ane: co('ination o% 'asic unit *ith a

saturated hydrocar'on side chain• Polydi(ethylsilo ane >PDMSB5& B2SiO is the

-oly(er used in (ost (edical a--lications• Most inert (aterial• Fiscosity de-ends u-on (olecular *eight


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Silicone

• Silicone i(-lants are used in 'reast+(alar+ nasal+ chinreconstruction/aug(entation

• Or'ital Coor reconstruction• &and surgeryL arthro-lasty+ Ce or

tendons reconstruction+ 'one 'loc0s-acers

• sed in (edical devices(anu%acturing+ cos(etics


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Poly(ers

PolytetraCouroethylene >PTEIB/ TeCon:• $nvented in Roy Plun0ett in 1 G• 5ar'on 'ac0'one *ith Couride side chains

• Porous >1 < (B+ allo*s tissue in gro*th• sed as surgical (eshes and vascular gra%ts


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-oly(ers

Polyester:• 5ontains an ester %unctional grou-• MIRS$=I#I is -olyster "'er (esh+ used in

herniorrha-hy+ (ore so%ter and hydro-hilicthan -oly-ro-ylene enhancing tissueingro*th

• D;5RO# is another %or( o% -olyester used in

vascular gra%t


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Poly(ers

Poly-ro-ylene:• 5ontains car'on 'ac0 'one *ith side chains

o% hydrogen and (ethyl grou-s

• sed as -oly-ro-ylene (esh and suture• &igh tensile strength *ith (ini(al tissue

reaction• &erniorha-hy and -elvic organ -rola-se

surgery• Main co(-lications are tissue/visceral

erosion and dense adhesions


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Poly(ers

Polyethylene:• 5ontains car'on 'ac0'one *ith hydrogen

side chains

• MIDPOR is highly dense -orous %or( used in%acial i(-lants• &igh tissue and vascular ingro*th (a0ing

-lace(ent and re(oval diNcult

• ;long *ith titaniu( (esh used in or'italCoor reconstruction


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Poly(ers

iodegrada'le -oly(ers:• Develo-ed to overco(e co(-lication o%

-er(anent i(-lants

• Degradation 'egins through hydrolysis oro idation• Mainly


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5era(ics• 5rystalline structure (ade u- o% inorganic and non (etallic

(olecules• Manu%actured under high -ressure and heat+ the -rocess called

Sintering.• 5era(ics have decreased %oreign 'ody reaction+ resisting 'acterial

coloni9ation+ high co(-ressive strength and tissue ingro*th• Main disadvantage+ they are 'rittle and 'rea0 easily undr tensile+

torsional and 'ending loads.• one aug(entation and re-lace(ent• 5alciu( -hos-hate co(es in t*o %or(ulations hydro ya-atite

>5a 1 >PO B6>O&B2B and tricalciu( -hos-hate >5a >PO B2B.• T5P has 'etter resor-tion and re-lace(ent rate 'y 'one• sed in nonloading reconstruction o% %ace and craniu(


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;dhesives and 8lues

• Eirst "'rin tissue adhesive asdescri'ed in 1 %or s0in gra%tadherence and 'eca(e co((erciallyavaila'le in 1 @G.

• 5yanoacrylate *as synthesi9ed in1 'ut severe tissue reactionli(ited its use.


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;dhesives and 8lues

Platelet 8els:• Derived %ro( PRP• Platelet layer o'tained %ro( a @ (l

centri%uged *hole 'lood is (i ed *ith'ovine thro('in• 5o(ercially availa'le %or( has high conc o%

"'rin and hence (ore eHective 'ut

e -ensive• sed in 'ro*/%aceli%t+ a'do(ino-lasty+ =Dand TR;M Ca- donor sites.


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;dhesives and 8lues

Ei'rin tissue adhesives:• 5onsists o% t*o (ain co(-onents+ "'rin and

thro('in+ *ith s(all a(ount o% %actor $$$

and calciu(• Dual syringe delivery syste(>s-rayer/(isterB allo* (i ing at ti(e o%a--lication

•Strength o% "'rin glue is directly -ro-otionalto "'rin concentration


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;dhesives and 8lues

5yanoacrylate:• Original cyanoacrylate is 'utyl<

cyanoacrylate+ short chain *ith ra-id 'rea0

do*n into %or(aldehyde and cyanoacetatecausing tissue irritation and *ounddehiscence

• To overco(e this long chain octyl<cyanoacrylate is develo-ed

• S0in closure in -lastic surgery


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S0in Su'stitutes

• ioengineered s0in su'stitutes have'eco(e (ainstay in *ound (anage(entin -ast 2 years.

• Manage(ent o% severe 'urns+ chronicvenous and dia'etic ulcers

• Three i(-ortant co(-onent in(anu%acturing – 5ell source – Tissue diHerentiation inducer – (atri


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S0in Su'stitutes

$ntegra:• ilayer s0in su'stitute

– Der(al layer has 'ovine collagen 'ase *ithglycosa(inoglycan chondroitin


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I-icel >cultured e-ider(al autogra%tsB:• 8ro*n %ro( -atient o*n 0eratinocytes

through a s(all s0in 'io-sy

• 5o cultured *ith T (urine "'ro'last%eeder cells• Once 2


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Der(agra%t:• Polyglactin (esh seeded *ith neonatal

"'o'lasts *hich -roduce collagen+ 8;8+

"'ronectin and other gro*th %actor• Mesh is resor' and re-laced *ith hu(antissue

• sed %or te(-orary and -er(anent coveringto inc success%ul ta0e o% (eshed STS8 in'urns+ venous and dia'etic ulcer

• I7uivalent to allogra%t


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;-ligra%:• ilayered s0in e7uivalent

– Der(al layer contains 'ovines ty-e 1 collagenand "'ro'lasts o'tained %ro( neonatal %ores0in

– I-ider(al layer has 0eratinocytes

• 5an 'e a--lied %resh *ith shel% li%e o% ! days• Mainly used in venous and dia'tic ulcers 'ut

can 'e used in con4unction *ith STS8 ine cised 'urns


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io-rosthetic (esh

• Derived %ro( decellularised(a((alian tissue >allogra%t or

enogra%tB• Der(is is (ost co((on source• $t is develo-ed to avoid the -ossi'le

side eHect o% synthetic -rosthetic(esh and -rovide (ore'ioco(-ati'le (aterial

• =i(it adhesions+ resist in%ection andtolerate cutanuous e -osure


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S(all intestine (ucosa:• ;lso called Surgisis• 5reated %ro( s(all intestinal (ucosa o% -igs

a%ter re(oval o% (ucosal+ (uscular andserosal layer• Dura'le yet 'ioche(ically rich and diverse

e tracellular (atri

• Eirst descri'ed %or vascular gra%t in 1 G• &ernia re-airs+ dural re-air+ 'ladderreconstruction and stress incontinencetreat(en


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&u(an ;cellular der(al (atri :• ;lloDer(+ ;lloMa + Ele &D• Derived %ro( donated hu(an der(is *hich

is -rocessed 'y %ree9e drying or che(icaldetergents• sed in i(-lant


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Porcine acellular der(al (atri :• 5ollaMend + Pr(acol + Strattice• More a'undant 'ut needs additional

-rocessing to -revent i((unogenic reaction'y che( cross lin0ing o% cllagen "'ers oren9y(atic deactivation o% antigen.


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Other 'io-rosthetic (esh -roducts:• ovine -ricardiu( >FeritasB is decellularised

and reduced i((ungenic collagen (atri

• ovine %etal der(is >Surgi(endB is acellularder(is derived %ro( %etal calves


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Euture (aterials

• Tissues s-eci"c res-onse• &y'rid 'io(aterials containing cells+

-oly(ers and gro*th %actors thusena'ling the( to )sense, theirsurrounding and ado-t to the needso% environ(ent

implants and biomaterials

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