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Grafts, Flaps and Tissue Transplantation

Yağmur AYDIN, M.D.

University of Istanbul, Cerrahpasa Medical FacultyDepartment of Plastic, Reconstructive and Aesthetic Surgery

Causes of Tissue Deficiency

Trauma

Tumoral resection

Congenital anamolies

RECONSTRUCTION

Tissue transplantation

RECONSTRUCTION

FunctionForm and Structure

Safety

BALANCE in RECONSTRUCTION

Defect RestorationDonor Area

RECONSTRUCTION LADDER

SIMPLE

Local Flaps

Primary Closure

Secondary Healing

COMPLEX Regional Flaps

Skin Graft

Free Flaps

Graft: tissue separated from its donor bed and relies on ingrowth of new vessels from the recipient tissuesVascularized 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 speciesXenogreft (hetereograft) : tissue transplanted between different species

Nomenclature

Tissue TransplantationAutologous

Skin Dermis, fat, fascia Cartilage Bone Muscle Nerve

AllogeneicXenogeneicAlloplastic materials

Metallic Seramic Polimeric

Tissue Transplantation

Basis of modern Plastic SurgeryLimited donör area for autologous tissue transplantationNonautologous tissues (Allogeneic, Xenogeneic) may be used for tissue deficiencyThey are rejected because of foreign body antigensLong 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 survivalHyperacute 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)

Biomaterials1. 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

BiocompatibleNontoxicNonallergenicNoncarcinogenicEasy to shape, remove, and sterilizeResistant to strainAble to be fabricated into specifically required formsProductive of no foreign-body inflamatuary responseMechanically reliableResistant to resorption and deformationNonsupportive of growth of microorganismRadiolucent ( 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 Autograft, allograft, xenograft

Bone Autograft, allograft

Cartilage Autograft, allograft, xenograft

Nerve Autograft, allograft

Tendon Only Autograft

Fascia 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

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 bodyProtect underlying structures from enviromental trauma by entry of pathogens and potentially toxic substancesMust allow considerable compressions and extentionsPassive regulation of intracellular fluid balance and active regulation of body temperature

Skin Grafts

Skin Autograft full thickness or partial thicknessrequire 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 essentialhematoma beneath the graft and insufficent immobilization are common causes of graft failureTo 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

Require well-vascularized bedprone to increased graft contraction and hypertrophic scarringPoor color and texture matchabnormal pigmentationLess than ideal cosmetic resulthighly susceptible to trauma

Better graft “takeLarge available donor siteExpansion of the split-thickness skin graft by meshing with expansion ratios from 1:1.5 to 1:9

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

Full thickness skin graft Split thickness skin graft

Advantages &Disadvantages

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 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 tissuesFrom 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

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)

Direct Cutaneous Vessels Indirect Cutaneous Vessels

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 Theoretical gain in length(%)30-30 2545-45 5060-60 7575-75 10090-90 120

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 Limited size Contraction 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) Nasal ala Columella Lateral nasal wall Nasa roof and lining reconstruction Short nose Septal perforation

Ear 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 reconstructionBone xenografts are not used nowadays because of sequester of all viable osteocyteCortical or cancellous bone graftRevascularization of cortical grafts may take a few monthsRevascularization of cancellous bone grafts are more rapidHealing 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 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 supplyThe use of cartilage autografts is widespread and includes nasal, auricular, craniofacial skeleton, and joint reconstructionCartilage is immunologically privileged due to the shielding of chondrocytes by its matrix, which is only weakly antigenicBoth 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 Costal cartilage(7,8 ve 9. ribs)

Ear reconstruction Nasal dorsal and alar area reconstruction

Ear cartilage: Lower eyelid support Nipple-aerola reconstruction Orbita floor reconstruction Temporomandibular joint repair

Nasal septal cartilage 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. SafeneousLateral femoral cutaneous nerveMedial antebrachial cutaneous nerveLateral antebrachial cutaneous nerve Dorsal antebrachial cutaneous nerveSuperficial radialal nerveServikal plexus cutaneous nervesInterkostal nerve


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