Transcript Graft

Grafts, Flaps and Tissue
Transplantation
Yağmur AYDIN, M.D.
University of Istanbul, Cerrahpasa Medical Faculty
Department of Plastic, Reconstructive and Aesthetic Surgery
Causes of Tissue
Deficiency
Trauma
Tumoral resection
Congenital anamolies
RECONSTRUCTION
Tissue transplantation
RECONSTRUCTION
Form and Structure
Function
Safety
BALANCE in RECONSTRUCTION
Donor Area
Defect Restoration
RECONSTRUCTION LADDER
Free Flaps
COMPLEX
Regional Flaps
Local Flaps
Skin Graft
SIMPLE
Primary Closure
Secondary Healing
Nomenclature
Graft: tissue separated from its donor bed and relies
on ingrowth of new vessels from the recipient tissues
Vascularized graft (or flap): remains attached to
donor blood supply or becomes revascularized via
microvascular anastomoses to recipient vessels
Autograft : tissue transplanted from one location to
another within the same individual.
İzograft : tissue transplanted from a genetically
identical donor to the recipient (syngeneic mice or
human monozygotic twins)
Allogreft (homograft) : tissue transplanted between
unrelated individuals of the same species
Xenogreft (hetereograft) : tissue transplanted
between different species
Tissue Transplantation
Autologous
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Skin
Dermis, fat, fascia
Cartilage
Bone
Muscle
Nerve
Allogeneic
Xenogeneic
Alloplastic materials
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Metallic
Seramic
Polimeric
Tissue Transplantation
Basis of modern Plastic Surgery
Limited donör area for autologous tissue
transplantation
Nonautologous tissues (Allogeneic,
Xenogeneic) may be used for tissue
deficiency
They are rejected because of foreign body
antigens
Long term immunosupression need to survive
longer
Advantages of Autologous Tissue
Transplantation
Easy integration
No rejection response
No fibrous capsule formation around the
transplant
Disadvantages of autologous
tissue transplantation
Donor area morbidity
Limited supply
More complex and longer operation
Resorption and deformation
Immunologic Response to Allogeneic
and Xenogeneic Tisuues
Cellular response (T cells)
Humoral immunologic response(B lymphocytes)
Matching of HL-A, HL-B ve HL-DR antigens are
important factor in long term survival
Hyperacute rejection occurs within the first few
minutes to hours after transplantation
Rejection response is less to tissues which
have few cells and lesser vascularity (cornea,
cartilage)
Biomaterials
1.
Metals: used in plating systems for craniomaxillofacial internal
fixation (Stainless steel, cobalt-chromium, pure titanium, titanium
alloys,and gold )
2.
Calcium ceramics: used as bone graft substitutes
(Hydroxyapatite, Tricalcium phosphate, hydroxyapatite cement)
3.
Polymers: used in both bone and soft tissue reconstruction
and augmentation (silicone, polyurethane, polyesters, nylon,
polyethylene, polypropylene, cyanoacrylates)
4.
Biologic materials: used in the treatment of depressed scars
and facial wrinkles (collagen, fibrel, hyaluronic acid)
Advantages of Biomaterials
No donor site morbidity
Less operative time
Easy availability and unlimited supply
Fabricated according to patient needs
No resorption or deformation
Ideal Implant
Biocompatible
Nontoxic
Nonallergenic
Noncarcinogenic
Easy to shape, remove, and sterilize
Resistant to strain
Able to be fabricated into specifically required forms
Productive of no foreign-body inflamatuary response
Mechanically reliable
Resistant to resorption and deformation
Nonsupportive of growth of microorganism
Radiolucent ( not interfere with CT and MR imaging)
Disadvantages of
Biomaterials
Rejection
Infection
Implant malposition or extrusion
Implant defects (broken, punctured)
Fibrosis around the implant because of
foreign body response
Tissue Transplantation in
Plastic Surgery
Skin
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Autograft, allograft, xenograft
Bone
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Autograft, allograft
Cartilage
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Autograft, allograft, xenograft
Nerve
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Autograft, allograft
Tendon
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Only Autograft
Fascia
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Autograft, allograft
Skin Anatomy
Skin Embryology
Derived form both ectoderm and mesoderm
Ectodermal skin appendages develop with formation
of epidermis at 11 weeks of gestation and complete
at 5 months
Suface of Ectoderm : Epidermis,Pilosebaceous glands,
Apocrine and eccrine sweat glands, Hair follicles, Nail units
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Neuroectoderm:
melamocytes, nerves, and specialized
sensory units
Mesoderm : Sructural components of dermis
(macrophages, mast cells, Langerhan’s cells,
Merkel cells, fibroblasts, blood and lymphatic vessels)
Skin Functions
The skin is the largest organ of the body
Protect underlying structures from
enviromental trauma by entry of pathogens
and potentially toxic substances
Must allow considerable compressions and
extentions
Passive regulation of intracellular fluid
balance and active regulation of body
temperature
Skin Grafts
Skin Autograft
full thickness or partial thickness
require a recipient bed that is well vascularized and
free of devitalized tissue and no bacterial
contamination (<105 microorganisms per gram of
tissue)
Close contact between the skin graft and its recipient
bed is essential
hematoma beneath the graft and insufficent
immobilization are common causes of graft failure
To optimize take of a skin graft, the recipient site must
be prepared before grafting
Skin Graft Survival
The transplanted skin derives its initial
nutrition via serum from the recipient site in
a process called “plasmatic imbibition” last
for 24 to 48 hours
The graft then gains blood supply from the
recipient bed by ingrowths of blood
vessels. This process of “inosculation“
begins within 48 hours
Skin Autograft
full thickness
partial thickness
Partial Thickness Skin
Grafts
Consist of entire epidermis and a portion of dermis
A thin split-thickness harvest site will generally heal within 7 days
SSG’s can be taken from anywhere on the body
The abdominal wall, buttocks, and thigh are common donor sites
for SSG’s
Skin Graft Donor Site
Healing
The donor site epidermis regenerates from
the immigration of epidermal cells originating
in the hair follicle shafts and adnexal
structures left in the dermis
A thin split-thickness harvest site (less than
10/1,000 of an inch) will generally heal within
7 days
Full-thickness skin graft harvest sites heal by
primary intention
Most Common Causes of
Autolous Skin Graft Failure
Hematoma, Seroma
Infection (> 105 organism/1gr tissue)
Shear force ( inadequate immobilization)
Poor vascularized bed (fibrozis,
radiotherapy; exposed bone, cartilage, or
tendon devoid of its periosteum, perichondrium,
or paratenon)
Full Thickness Skin Graft
contains the entire dermis (adnexal structures such
as sweat glands, sebaceous glands, hair follicles,
and capillaries)
Usually harvest from skin is thin(upper eyelid,
postauricular area, or supraclavicular area). Other
harvest sites are hairless groin, antecubital fossa,
distal forearm, prepuce
FSG harvest sites can be closed primarily or applied
a SSSG from another body part
Advantages &Disadvantages
Full thickness skin graft
Require well-vascularized bed
prone to increased graft
contraction and hypertrophic
scarring
Poor color and texture match
abnormal pigmentation
Less than ideal cosmetic result
highly susceptible to trauma
Better graft “take
Large available donor site
Expansion of the split-thickness
skin graft by meshing with
expansion ratios from 1:1.5 to
1:9
Split thickness skin graft
Take under less favorable condition
The less secondary contracture
Good color and texture match
Excellent cosmetic result
Potential for growth
less reliable graft “take
Limited donor site
Sensory return
Graft sensation is regained as nerves
grow into the graft
Sensory recovery begins at around 4-5
weeks and is completed by 12-24
months
Pain,light touch, and temperature return
in that order
Skin Allografts
Skin allograft was the first “organ” transplant
achieved and constituted the foundation of modern
transplant immunology
strongly antigenic and is subject to rejection ( 10 days
in burns)
Obtained from relatives or human corpse (frozen and
stored)
beneficial in large burns (> % 50) as a biologic
dressing
Frozen and stored or may be used immediately with
cyclosporine immunusupression
Skin Xenografts
Pig skin grafts can be used as temporary
biologic dressings in large burns
Hyperacute rejection occurs within the first
few minutes to hours after transplantation
Advantages
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Cheap, easy availablility, easy storage and sterility
Skin Flaps
Skin Flaps
Unlike a graft, a flap has its own blood supply
Consist of skin and subcutaneous tissue that
are transferred from one part of the body to
another with a vascular pedicle or attachment
to the body being maintained for nourishment
When skin flaps are used?
Covering recipient beds that have poor vascularity
Reconstructing the full thickness of the eyelids, lips,
ears, nose, and cheeks; and padding body
prominencies (i.e., for bulk and contour)
It is necessary to operate through the wound at a
later date to repair underlying structures
Muscle flaps may provide a functional motor unit or a
means of controlling infection in the recipient area
The Cutaneous Arteries
arise directly from the underlying source (segmental or distributing)
arteries, or indirectly from branches of those source arteries to the deep
tissues
From here the cutaneous arteries follow the connective tissue framework
of the deep tissues, either between (septocutaneous) or within the
muscles (musculocutaneous)
They then pierce that structure, usually at fixed skin sites. ultimately
reaching the subdermal plexus
Direct Cutaneous Vessels
Indirect Cutaneous Vessels
Schematic diagram of the direct (d) and indirect (i) cutaneous perforators of a source artery and
their relationship to the deep fascia (arrow), the intermuscular septa and muscle (shaded area)
Skin Blood Vessels
Patterns of Blood Supply to the Skin
Direct cutaneous pedicle
Fascicutaneous pedicle
Musculocutaneous pedicle
Skin Flap Classification
Proximity to defect : Local
Distant
Skin Flap Classification
Composition:Cutaneous
Fasciocutaneous
Musculocutaneous
Osteocutaneous
Skin Flap Classification
Method of movement: Advancement
Rotation
Transposition
Interpolation
Free
Transposition Flap
Bilobed Flap
Z Plasty
revise and redirect existing scars or
provide additional length in the setting of
scar
Angles of Z-plasty
30-30
45-45
60-60
75-75
90-90
Theoretical gain in length(%)
25
50
75
100
120
Skin Flap Classification
Specialized : Sensory
Tendon
Hair bearing
Skin Flap Classification
Blood supply :
Random
Axial pattern
Fasciocutaneus
Musculocutaneous
Old Fashioned Classification
of Skin Flaps
Vascular territories of the most
commonly used axial pattern flaps
Groin Flap
based on the circumflex
superficial iliac artery and vein
Skin Flap Classification
Manipulation before transfer
Delay
Expansion
Prefabrication
Prelamination
Other Flaps
Muscular
Bone
Visceral organ (jejenum, sigmoid colon)
Omentum
Free Composite Grafts
Contain two or more tissue (dermis-cartilage,
dermofat, skin-muscle, pulpa)
Need well-vascularized bed
Poor vascularization and graft taking
Stasis and necrosis in the graft because of
insufficent venous and lymphatic return
Results is not optimal
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Limited size
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Contraction
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Contur problem because of bowing
Enhancing Survival of
Composite Grafts
Well vascularized bed, no fibrosis
Atrumatic technique
Postoperative cooling
> 5 mm distant from the nearest vascular
bed is at risk for necrosis
Center of graft is never more than 5-8 mm
away from a blood supply
Composite Grafts in Plastic
Surgery
Nose (from ear or nasal septum)
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Nasal ala
Columella
Lateral nasal wall
Nasa roof and lining reconstruction
Short nose
Septal perforation
Ear
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Helical rim
Chonca
Tragus
Eyebrow (scalp)
Nipple (opposite nipple or ear lobule)
Eyelid (septal chondromucosal graft)
Bone Transplantation
Both bone autograft and allografts are used for bone
defect reconstruction
Bone xenografts are not used nowadays because of
sequester of all viable osteocyte
Cortical or cancellous bone graft
Revascularization of cortical grafts may take a few months
Revascularization of cancellous bone grafts are more
rapid
Healing of vascularized bone grafts are better. Particularly
suitable in a field after trauma, cronic scarring, or prior
radiation. Biomecanically are superior to nonvascularized
grafts
Bone Graft Donor Areas
Cranium (cortical)
Thorax (split rib grafts)
İliac ( good quality cortical and cancellous bone
source)
Tibia (cancellous )
Others
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Distal radİUs, proXimal ulna (hand surgery)
Fibula (esp. vascularized flap)
Metatars
Tendon Grafts
Only if primary or delayed primary repair is
not feasible
Contrindicated if there is stiff joints, adherent
extensor tendons, and inadequate skin cover
Only autograft
Unacceptable amount of host reaction and
adhesion after allografts and xenografts
Donor Areas for Tendon Graft
Palmaris longus (usually)
Plantaris
Middle 3 toes extensor tendons
Cartilage Grafts
Cartilage has no intrinsic blood supply
The use of cartilage autografts is widespread and
includes nasal, auricular, craniofacial skeleton, and
joint reconstruction
Cartilage is immunologically privileged due to the
shielding of chondrocytes by its matrix, which is only
weakly antigenic
Both chondrocytes and matrix are subject to
xenogeneic mechanisms of rejection with a generally
poorer outcome in comparison. There is only small
number of usage
Donor Areas for Cartilage
Graft
Choose according to aim
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Costal cartilage(7,8 ve 9. ribs)
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Ear cartilage:
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Ear reconstruction
Nasal dorsal and alar area reconstruction
Lower eyelid support
Nipple-aerola reconstruction
Orbita floor reconstruction
Temporomandibular joint repair
Nasal septal cartilage
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Aestetic Rhinoplasty and Nasal reconstruction
Nerve Grafts
The nerve graft acts as a biologic conduit for the
regenerating axons
Vascularized nerve grafts are theoretically
advantageous particularly in scarred beds
Other “conduits” used as nerve grafts have
included autologous vein, silicone tube seeded
with Schwann cells, and freeze fractured
autologous muscle
Donor Areas for Nerve
Graft
Sural sinir (most often)
N. Safeneous
Lateral femoral cutaneous nerve
Medial antebrachial cutaneous nerve
Lateral antebrachial cutaneous nerve
Dorsal antebrachial cutaneous nerve
Superficial radialal nerve
Servikal plexus cutaneous nerves
Interkostal nerve