Key notes on plastic surgery/Adrian M. Richards

1
28 GENERAL PRINCIPLES
Seroma
Any collection of fluid under the graft reduces the likelihood of its taking
successfully.
Shear
• This is a lateral force placed on a graft.
• It results in the disruption of the delicate connections between the graft and its
bed and consequently reduces the likelihood of successful graft take.
Inappropriate bed
• Skin grafts will not survive on cartilage, tendon and endochondral bone denuded
of periosteum.
• Membranous bone, found in some areas of the skull, will accept a skin graft.
• Grafts on previously irradiated tissue are prone to failure.
Technical error
• An assortment of technical errors can result in graft failure.
• Examples include placing the graft upside down or allowing it to dry out before
application.
Bone healing and bone grafts
• All bones are derived from mesenchyme.
• All are composed of an organic matrix (osteoid) which is mineralized by the
calcium salt hydroxyapatite.
Bones are formed by one of two different mechanisms: (i) intramembranous
ossification; or (ii) endochondral ossification.
Intramembranous ossification
• Bones formed by intramembranous ossification include the flat bones of the
face, calvarium and ribs.
• Intramembranous ossification occurs by direct deposition of bone within a
vascularized membranous template.
Endochondral ossification
• Endochondral bones develop from a cartilage precursor.
• Bones formed by endochondral ossification include all the long bones and the
iliac crest.
Bone structure
• All bones have an outer cortical layer and an inner cancellous layer.
• The cancellous portion of membranous bone is found within the diploic
space.
• Cancellous bone consists of loosely woven trabeculae made up of organic and
inorganic bone.