*Plastics Flashcards
CREEP
INCREASE IN STRAIN seen when skin is under CONSTANT STRESS
occurs in a matter of minutes and is due to extrusion of fluid from the dermis and a breakdown of the dermal framework
Stress
force applied per cross-sectional area
F/A
Strain
CHANGE IN LENGTH divided by the ORIGINAL LENGTH of a given tissue when a force is applied
Stress Relaxation
the decrease in stress when skin is held in tension at a constant strain for a given time;
this occurs over a matter of days to weeks and is due to an increase in skin cellularity and the permanent stretching of skin components
what is good “take” of a graft?
- absence of infection
- perfect hemostasis
- good dressing
- absence of motion
how does thickness of graft affect “take” and function?
- thinner the graft, the better the “take”
- the thicker the graft, the better the function
which part of amniotic tissue allografts are known to contain maternal antigens?
Chorion layer: on the maternal side of the placenta; contains maternal antigens
Theory is that by removing chorion layer, less likely to have host rxn
(other side is Amnion)
which side is against the wound in amniotic tissue allografts?
STROMAL side down against wound (Sticky and gelatinous side)
as compared to smooth/shiny epithelial surface
amniotic membrane components
- structural collagen: type I, 3, 4, 5, 7
- ECM proteins: Fibronectin, proteoglycans, glycosaminoglycans
- Growth factors: EGF, TGF, FGF, PDGF, VEGF
- Regulating proteins: MMPs, TIMPs, IL-K
Amniotic Membrane Allografts:
benefits
examples of Amniotic Membrane Allografts
affinity, amniofix, biofix, epifix, grafix, neox, nucel, nushield, revitalon, xwrap
compare FTSGs and STSGs
reasons for skin graft failure
Transpositional Flap
Rotational Flap
Bilobed Flap
Rhomboid (Limberg) Flap
Longitudinal axis is parallel to the line of minimal skin tension
Kutler-Type Biaxial V-Y
(Advancement Flap)
Atasoy-Type Plantar V-Y
(Advancement Flap)
Z-Plasty
good for linear scar contractures
V-YPlasty
Unidirectional skin-lengthening technique. The apex of the “V” is placed at the point of maximal skin tension
Derotational Skin Plasty for Fifth Digits
Performed in conjunction with an arthroplasty. Acts to correct for the varus (frontal) and hammering (sagittal) of the digit. The incision is made from distal-medial to proximal-lateral.
Desyndactyly Procedure
Place needles from dorsal to plantar to line up apices.
Tsuge “Inchworm” Plastic Reduction Procedure
Fishmouth incision is made around the toe just dorsal to phalange. The dorsal skin is retracted, allowing the proximal skin to buckle. The tip of the toe is excised, and the nail may be reduced in width, if desired. Six to eight weeks after initial procedure, the dorsal redundant skin is excised.
Ollier Incision
Indications:
- triple arthrodesis and resection of a calcaneonavicular bar;
- incision may be extended to expose the subtalar, calcaneocuboid, and talonavicular joints;
- wound usually heals well because the proximal flap is dissected full thickness and the skin edges are protected during retraction;
- *- Cautions:**
- preserve dorsal cutaneous branches of superficial peroneal nerve which cross the incision;
- *- Incision:**
- begins over dorsolateral aspect of the talonavicular joint,
- continue incision obliquely & inferoposteriorly to end about 1 inch inferior to lateral malleolus
DuVries Incision
- Medial longitudinal incision
- Limited exposure
Indicates w/ classic heel spur operation; however, may sever branches of medial calcaneal nerve → produces nerve entrapments
Cincinnati Incision
- Transverse incision that involves extensive dissection of the posterior, medial, and lateral aspects of the foot and ankle
- Do not perform in greater than 4-year-olds
- Classic soft tissue release for clubfoot
Lateral Extensile Incision
- This is a full-thickness incision down to bone.
- aka “sinus tarsi apprach”
- Indications
- displaced intraarticular calcaneal fractures
- Designed to outline the distribution of the peroneal artery, also protects the sural nerve, and peroneal tendons.
