This is an in-depth explaination of the use of grafts in oral and maxillofacial surgery.

1. GRAFTS
DR. LANRE-OYEBOLAO. N. BDS 2019,WASSCE 2014.
DEPARTMENT OF ORAL AND MAXILLOFACIAL SURGERY.
LAGOS UNIVERSITYTEACHING HOSPITAL.

2. OUTLINE
• Introduction
• Classification of Grafts
• Reconstruction Ladder
• Skin Grafts
• Bone Grafts
• Conclusion
• References

3. INTRODUCTION
• When a deformity needs to be reconstructed, either grafts or
flaps can be employed to restore normal function and/or
anatomy. For instance, when wounds cannot be closed primarily
or allowed to heal by secondary intention, either grafts or flaps
can be used to close an open wound.
• Grafts : Grafts are harvested from a donor site and transferred to
the recipient site without carrying its own blood supply. It relies
on new blood vessels from the recipient site bed to be generated
(angiogenesis).

4. CLASSIFICATION OF GRAFTS
• Grafts can be classified in various ways:
• 1. Based on the tissue involved:
• Skin Grafts
• Bone Grafts
• Nerve Grafts
• Fat Grafts
• Tendon Grafts
• Muscle Grafts
• Cartilage Grafts
• Composite-A graft that has more than one component, i.e. cartilage and
skin graft, dermal-fat graft.

5. CLASSIFICATION OF GRAFTS
• 2. Based on the origin of the graft:
•Autograft: Same individual
•Allograft:Tissue from one individual to another of the
same species with a different genotype
•Xenograft (unlike species) different species, ie pig skin
•Isograft (genetically identical individual; monozygotic
twins)
•Synthetic — Biobrane, Integra

6. RECONSTRUCTION LADDER

7. SKIN GRAFTS
•A skin graft is a sheet of skin (epidermis & varying
amounts of dermis) that is detached from its own blood
supply and placed in a new area of the body.
•To provide permanent skin replacement which is supple
sensate and durable.
•Functions:
•biologic cover, thermoregulation and aesthetics.

8. INDICATIONS
• Acute skin loss e.g flame burns, frictional burn
• Chronic skin loss e.g chronic ulcers in head and neck cancers.
• Adjunct to some procedures e.g scar excision
• Miscellaneous indications.
• CONTRAINDICATIONS
• Unhealthy granulation tissue
• Streptococcal infection

9. TYPES OF SKIN GRAFTS

10. TYPES OF SKIN GRAFTS

11. TYPES OF SKIN GRAFTS
• Epidermis provides protective barrier against:
• Mechanical damage
• Microbe invasion
• Water loss.
• Dermis provides:
• Mechanical strength (collagen & elastin)
• Sensation (temp, pressure, proprioception)
• Thermoregulation (vessels & sweat gland)

12. TYPES OF SKIN GRAFTS
SPLIT SKIN GRAFT FULLTHICKNESS SKIN GRAFT
THICKNESS Epidermis +
Dermis -
Epidermis and Dermis +
DONOR AREAS Thigh, Legs, Upper arms, Fore
arms, trunk, buttocks, scalp.
Post auricular, supra clavicular,
groin, flexor aspect of joints.
DONOR AREA HEALING By Epithelization Primary Closure
COLOUR CHANGE Hyper pigmented Retains color
RESISTANCETOTRAUMA Poor tolerance Better resistance
HAIR GROWTH No growth Grows after a long time

13. ADV and DISADV

14. PATHOPHYSIOLOGY
• Full thickness and split thickness skin grafts survive by the same
mechanisms
• a. Plasmatic imbibition — Initially, the skin grafts passively
absorbs the nutrients in the wound bed by diffusion.
• Initial graft ischemia (24 – 48 hrs)
• Fibrin adhesion Grafts gain weight (40%)

15. PATHOPHYSIOLOGY
• b.Vascular Inosculation — By day 3, the cut ends of the vessels on
the underside of the dermis begin to form connections with
those of the wound bed.
• After 48 hours
• Fine vascular network in the fibrin layer
• Capillary buds make contact with the graft
• Blood flow is established
• Skin graft becomes pink.

16. PATHOPHYSIOLOGY
• c. Angiogenesis — By day 5, new blood vessels grow into the
graft and the graft becomes vascularized
• Neovascularization & Revascularization
• Formation of new vascular channels
• Combination of old & new vessels
• Fibroblast proliferation
• Collagen linkages

17. FAILURE OF SKIN GRAFTS
• Skin grafts fail by four main mechanisms
• a. Poor wound bed — Because skin grafts rely on the underlying
vascularity of the bed, wounds that are poorly vascularized with bare
tendons or bone, or because of radiation, will not support a skin graft.
• b. Sheer — Sheer forces separate the graft from the bed and prevent
the contact necessary for revascularization and subsequent “take”.
• c. Hematoma/seroma — Hematomas and seromas prevent contact of
the graft to the bed and inhibit revascularization.They must be
drained by day 3 to ensure “take”
• d. Infection — Bacteria have proteolytic enzymes that lyse the protein
bonds needed for revascularization. Bacterial levels greater than
10are clinically significant

18. COMPLICATIONS
•Donor site morbidity
•Graft loss
•Hyperpigmentation
•Poor cosmesis

19. BONE GRAFTS
• INTRODUCTION
• Bone grafting is a surgical procedure done in order to fill the
defects in cortical and cancellous bones formed secondary to
• Trauma
• Tumor
• Infections and other conditions to fasten the bone healing.

20. TYPES OF BONE GRAFTS
•Autograft: harvested from the patient’s own body
•Allograft: Cadaveric bone
•Synthetic: Often made of hydroxyapatite or other
naturally-occurring and biocompatible substances with
similar mechanical properties to bone.
•Xenograft (unlike species)
•Isograft (genetically identical individual; monozygotic
twins)

21. CLASSIFICATION
• Origin:
• Autogenous
• Allogenous
• Blood supply:
• Nonvascularised
• Vascularised
• Type of bone :
• Cortical
• Cancellous
• Corticocancellous

22. INDICATIONS
• To promote union or fill defects in
• Fresh fractures
• Delayed union
• Malunion
• Osteotomies
• To fill cavities/defects resulting from cysts, tumors etc
• To bridge joints and provide arthrodesis

23. FUNCTIONS OF BONE GRAFTS
• Mechanical and
• Biologic function
• Depending on the desired clinical outcome, one function may be
more important than the other.
• Continuity defect
• Discontinuity defect
• Augmentation of the jaws

24. ESSENTIAL PROPERTIES OF BONE GRAFT
•Osteogenesis: Synthesis of new bone from cells derived
from graft and host
•When correctly handled, cells from cortical and
cancellous grafts can survive the transfer to the host site
and form new bone that is critical in the initial phase of
bone repair.

25. OSTEOINDUCTION
• Osteoinduction is the process by which mesenchymal stem cells
(MSCs) at and around the host site are recruited to differentiate
into chondroblasts and osteoblasts.
• Recruitment and differentiation are modulated by graft matrix-
derived growth factors whose activity is triggered when bone
mineral is removed.
• These growth factors include bone morphogenetic proteins -2, -
4, and -7, which are members of the transforming growth factor-
super-family.
• IN SUMMARY: Stimulation of synthesis
• Growth factor is responsible (BMP)

26. OSTEOCONDUCTION
• Osteoconduction is the process by which an ordered, spatial
three-dimensional in growth of capillaries, perivascular tissue,
and MSCs takes place from the host site along the implanted
graft.This scaffold permits the formation of new bone along a
predictable pattern determined by the biology of the graft and
the mechanical environment of the host-graft interface.
• Provision of scaffold for formation of new bone

27. AUTOGENOUS GRAFTS
• “Gold standard”
• May provide osteoconduction, osteoinduction and osteogenesis
• Disadvantage could be
• Donor site morbidity i.e. harvesting autograft requires an
additional surgery at the donor site which has its own
complications- inflammation, infection, and chronic pain
• Quantities of bone tissue that can be harvested are also limited.

28. CORTICAL BONE GRAFTS
• Less biologically active than cancellous bone – Less porous, less
surface area, less cellular matrix – Prologed time to
revascularizarion
• Provides more structural support – Can be used to span defects
• Vascularized cortical grafts – Better structural support due to
earlier incorporation

29. CANCELLOUS BONE GRAFTS
• Three dimensional scaffold (osteoconductive)
• Osteocytes and stem cells (osteogenic)
• A small quantity of growth factors (osteoinductive)
• Little initial structural support
• Can gain support quickly as bone is formed

30. VASCULARIZED GRAFTS
• Bone is transferred with its blood supply which is anastomosed to
vessels at recipient site.
• Available donor sites:
• Iliac crest (with one circumflex artery)
• Fibula (peroneal artery)
• Radial shaft (interosseus artery)
• Vascularized grafts remain completely viable and incorporated
like that of fracture healing

31. SITES OF AUTOGENOUS BONE GRAFT
• Cortical
• Fibula
• Rib
• Cancellous
• Iliac crest,
• ProximalTibia
• Radius
• Corticocancellous
• Iliac crest

32. AUTOGRAFT HARVEST
• Cancellous –
• Iliac crest (most common)
• Anterior- taken from gluteus medius pillar
• Posterior- taken from posterior ilium near SI joint
• May offer local source for graft harvest
• Greater trochanter, distal femur, proximal or distal tibia, calcaneus,
olecranon, distal radius, proximal humerus
• Cancellous harvest technique – Cortical window made with
osteotomes

33. AUTOGRAFT HARVEST
• Cortical
• – Fibula common donor
• Avoid distal fibula to protect ankle function
• Preserve head to keep Ligaments, hamstrings intact
• – Iliac crest
• Cortical or tricortical pieces can be harvested in shape to fill
defect

34. ALLOGRAFTS
• Used in small children where sufficient graft is not available from
donor site
• In adults where large defects have to be filled like:
• Periprosthetic long bone fracture
• RevisionTotal joint surgeries.
• Reconstruction after tumor excision

35. ALLOGENIC GRAFTS
• Available in various forms – Processing methods may vary
between companies / agencies
• Fresh
• Fresh Frozen
• Freeze Dried
• Advantage –
• No donor site morbidity
• Large amount can be used

36. PROPERTIES OF AUTOGRAFTS AND
ALLOGRAFTS

37. FACTORS CONSIDERED IN BONE GRAFTING
•Graft Site preparation: Graft site preparation is
important to the success of the grafting procedure, and
meticulous adherence to surgical principles is essential.
•Care must be taken to ensure adequate surface area
contact between the graft and recipient site without
interposition of soft tissue.

38. GRAFT SITE PREPARATION
•Overzealous use of a reamer or burr may cause excessive
heat generation, leading to necrosis at the graft site.
•Efforts must be made to preserve the osteogenicity of
corticocancellous autografts, including decreased
harvest-to-implant time, storage in covered containers,
and attention to hydration.

39. FACTORS CONSIDERED IN BONE GRAFTING
•Other factors include:
•Decortication or perforation of cortex
•Intimate contact
•Rigid fixation
•Preservation of periosteum
•Effect of host/recipient periosteum on bone graft healing
•Growth factors
•Addition of bone substitutes (BiOss, algipore)

40. DECORTICATION/ PERFORATION OF CORTEX
Cortical perforation Graft placement after

41. INCORPORATION OF GRAFT
•Primary phase
•Hemorrhage
•Inflammation
•Accumulation of haemopoietic cells including
neutrophills, macrophages and osteoclasts
•Removal of necrotic bone

42. •Osteoconductive factors released from graft during
resorption and cytokines released during inflammation.
•Recruitment and stimulation of mesenchymal stem cells
to osteogenic cells.
•Active bone formation

43. •Second phase
•Osteoblasts lines dead trabecule and lay down osteoid
•Haemopoietic marrow cells forms new marrow in
transplanted bone
•Remodeling i.e. woven bone slowly being transformed
into lamellar bone by coordinated activities of
osteoblasts and osteoclasts
•Incorporation of graft

44. HOST RESPONSETO CANCELLOUSVS
CORTICAL BG
•In cortical bone graft first osteoclastic resorption then
osteoblastic activity
•Where as in cancellous bone graft bone formation and
resorption occurs simulaneously called creeping
substitution
•Therefore cancellous bone graft incorporates quickly
•But does not provides immediate structural support

45. LOCAL AND SYSTEMIC FACTORS INFLUENCING
GRAFT INCORPORATION
•Local Positive
•Good vascularity at graft site
•Large surface area
•Mechanical stability
•Growth factors

46. •Local negative
•Radiation
•Tumour
•Mechanical instability
•Local bone disease
•Denervation
•Infection

47. •Systemic positive
•Growth Hormones
•Somatomedin
•VitaminsA and D
•Insulin
•Parathroid hormone

48. •Systemic negative
•Corticosteroids
•NSIADS
•Chemotherapy
•Smoking
•Sepsis
•Diabetes
•Malnutrition
•Metabolic bone disease

49. CONCLUSION
• Several factors dictate the successful incorporation of graft,
including the type of graft used: the site of implantation, the
vascularity of the graft and the host-graft interface.
• Also the immunogenetics between the donor and the host,
preservation techniques, local and systemic factors, and the
mechanical properties that depend on the size, shape, and
type of graft used are also important.
• It is therefore important for the surgeon to have a detail
knowledge about grafts inorder to have a successful graft
surgery.

50. REFERENCES
• 1. Mathes, S.J. Reconstructive Surgery: Principles,Anatomy
andTechniques. NewYork, Elsevier Science, 1997.
• 2. McCarthy, J.G. (ed). Plastic Surgery, vol. 1. NewYork:
Elsevier Science, 1990.
• 3. Mary H. McGrath & Jason Pomerantz; plastic surgery;
Sabiston text book of surgery, chapter 13; 19th edition; 2012.
• 4. Joseph J. Disa, Eric G. Halvorson & Himansu R. Shah;
Surface Reconstruction Procedures;ACS, Principles &
practice, 2007 edition
• 5. Khan SN, Cammisa FP Jr, Sandhu HS, Diwan AD, Girardi
FP, Lane JM.The biology of bone grafting. J Am Acad Orthop
Surg. 2005 Jan-Feb;13(1):77-86. PMID: 15712985

51. REFERENCES
•6. Stevenson S. Enhancement of fracture healing with
autogenous and allogeneic bone grafts. Clin Orthop Relat
Res. 1998 Oct;(355 Suppl):S239-46. doi:
10.1097/00003086-199810001-00024. PMID: 9917643.
•7. Pape HC, Evans A, Kobbe P. Autologous bone graft:
properties and techniques. J OrthopTrauma. 2010
Mar;24 Suppl 1:S36-40. doi:
10.1097/BOT.0b013e3181cec4a1. PMID: 20182233