Grafts, Flaps and Tissue Transplantation Yamur AYDIN, M.D. University of Istanbul, Cerrahpasa Medical Faculty Department of Plastic, Reconstructive and

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Grafts, Flaps and Tissue Transplantation Yamur AYDIN, M.D. University of Istanbul, Cerrahpasa Medical Faculty Department of Plastic, Reconstructive and Aesthetic Surgery Slide 2 Causes of Tissue Deficiency Trauma Tumoral resection Congenital anamolies RECONSTRUCTION Tissue transplantation Slide 3 RECONSTRUCTION FunctionForm and Structure Safety Slide 4 BALANCE in RECONSTRUCTION Defect Restoration Donor Area Slide 5 RECONSTRUCTION LADDER SIMPLE Local Flaps Primary Closure Secondary Healing COMPLEX Regional Flaps Skin Graft Free Flaps Slide 6 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. zograft : 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 Nomenclature Slide 7 Tissue Transplantation Autologous Skin Dermis, fat, fascia Cartilage Bone Muscle Nerve Allogeneic Xenogeneic Alloplastic materials Metallic Seramic Polimeric Slide 8 Tissue Transplantation Basis of modern Plastic Surgery Limited donr 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 Slide 9 Advantages of Autologous Tissue Transplantation Easy integration No rejection response No fibrous capsule formation around the transplant Slide 10 Disadvantages of autologous tissue transplantation Donor area morbidity Limited supply More complex and longer operation Resorption and deformation Slide 11 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) Slide 12 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) Slide 13 Advantages of Biomaterials No donor site morbidity Less operative time Easy availability and unlimited supply Fabricated according to patient needs No resorption or deformation Slide 14 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) Slide 15 Disadvantages of Biomaterials Rejection Infection Implant malposition or extrusion Implant defects (broken, punctured) Fibrosis around the implant because of foreign body response Slide 16 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 Slide 17 Skin Anatomy Slide 18 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, Langerhans cells, Merkel cells, fibroblasts, blood and lymphatic vessels) Slide 19 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 Slide 20 Skin Grafts Slide 21 Skin Autograft full thickness or partial thickness require a recipient bed that is well vascularized and free of devitalized tissue and no bacterial contamination ( Most Common Causes of Autolous Skin Graft Failure Hematoma, Seroma Infection (> 10 5 organism/1gr tissue) Shear force ( inadequate immobilization) Poor vascularized bed (fibrozis, radiotherapy; exposed bone, cartilage, or tendon devoid of its periosteum, perichondrium, or paratenon) Slide 29 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 Slide 30 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 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 graftSplit thickness skin graft Advantages &Disadvantages Slide 31 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 Slide 32 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 Slide 33 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 Slide 34 Skin Flaps Slide 35 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 Slide 36 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 Slide 37 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 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 Slide 38 Skin Blood Vessels Slide 39 Slide 40 Patterns of Blood Supply to the Skin Direct cutaneous pedicle Fascicutaneous pedicle Musculocutaneous pedicle Slide 41 Skin Flap Classification Proximity to defect : Local Distant Slide 42 Skin Flap Classification Composition:Cutaneous Fasciocutaneous Musculocutaneous Osteocutaneous Slide 43 Skin Flap Classification Method of movement:Advancement Rotation Transposition Interpolation Free Slide 44 Slide 45 Slide 46 Slide 47 Slide 48 Transposition Flap Slide 49 Bilobed Flap Slide 50 Z Plasty revise and redirect existing scars or provide additional length in the setting of scar Angles of Z-plasty Theoretical gain in length (%) 30-3025 45-4550 60-6075 75-75100 90-90120 Slide 51 Skin Flap Classification Specialized : Sensory Tendon Hair bearing Slide 52 Skin Flap Classification Blood supply : Random Axial pattern Fasciocutaneus Musculocutaneous Slide 53 Old Fashioned Classification of Skin Flaps Slide 54 Vascular territories of the most commonly used axial pattern flaps Groin Flap based on the circumflex superficial iliac artery and vein Slide 55 Skin Flap Classification Manipulation before transfer Delay Expansion Prefabrication Prelamination Slide 56 Other Flaps Muscular Bone Visceral organ (jejenum, sigmoid colon) Omentum Slide 57 Free Composite Grafts Contain two