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58 Cards in this Set
- Front
- Back
T or F
subq pedicle grafts have no practical use in dogs |
true
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list 3 types of flap classification
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a.circulation
b.compound or composite c.location in relation to recipient bed |
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what is the subdermal plexus fed by in dogs and cats
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terminal branches of direct cutaneous arteries
both of which are associated with panniculus layer |
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what is an axial pattern ?
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a pedicle graft that incorporates a direct cutaneous artery and vein
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what is a compound flap?
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incorporates skin with other tissues including muscle, fat, and cartilage
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what are myocutaneous grafts most useful for?
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closure of thoracic and abdominal wall defects
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name the two basic types of local flaps?
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rotating flaps
advancement flaps |
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true or false
increasing the width of a pedicle graft increases its total surviving length |
false
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what is delay phenomenon?
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method used to augment survival and improve circulation of a flap
staged flap development flaps may be trained to rely on their pedicle by gradually cutting of other blood supply -incison and suture of of proposed flap borders -partial division of a pedicle of a flap -temporary occlusion of one pedicle of a bipedicle flap -tissue expansion |
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according to hoffmeister;s studies, circulatory efficiency after initial flap elevation can decline when?
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immediately or during period of 3 to 7 days
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do tissue expanders exert a delay effect on the overlying skin?
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yes
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what should you do if there is chronic GT present in the recipient bed?
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chronic GT should be excised. A healthy bed will appear in 3-5 days
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what type of flap is commonly used for closure of triangular defects?
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rotation flap
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name the differenct types of local flaps?
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1. rotation flap
2. transposition flap 3. interpolation flap 4. skinfold or pedicle flap 5. advancement flap (single and bipedicle) |
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how often are direct pedicle flaps divided?
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10-14 days after initial transfer, in stages. 1/2 to 1/3 every 2-3 days to avoid ischemia
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why are flaps frequently thicker than surrounding skin after transfer?
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inflammation and fibrous CT deposition
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how much should a tube flap be increased to compensate for flap shrinkage?
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25% in length and width
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list 3 techniques used to move tube flaps by migration
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a. caterpilling
b. waltzing c. tumbling |
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lines of tension
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what are subdermal plexus flaps?
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full thickness "tongues of skin" usually detached along 3 or 4 borders
tradiltionally include skin and sq relay on collateral circulation to sq (deep) plexus |
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width of hairy skin?
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0.5-5mm
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what vessels are composite flaps based on
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subdermal plexus or direct cutaneous artery
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what happens to perfusion with elevation of single and bipedicle flaps
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drops to 10% (single)
40% (bipedicle) in delayed flaps circulation rises to 120% and 150% at 3 weeks re-elevation at 3 weeks perfusion is 90% normal: major advantage of delayed flaps |
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what are the major factors contributing to the delay phenomenon
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changes in sympathetic tone
dilation of choke vessels changes in tissue metabolism neovascularization |
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what happens to vasculature during delay?
what are choke vessels? |
initially adrenergic tone causes vasocontriction, then NE depletion leads to vasodilation, neovascularization occurs, vessels run parallel to long axis of the flap.
choke vessels, the vessels that link adjacent territories increase in size and number. |
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how long is required for optimal vascular delay?
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at least 2 weeks
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what types of flaps benfeit from delay?
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ischemic flaps
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what is pavletics approach to tube flaps?
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total 3 week delay
at 18d, half of the pedicle is divided, remainder is severed 3 days later |
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how should you prepare the recipient site prior to flap placement?
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-make sure its free of infection or debris, necrotic debris
-granulation tissue should be well vascularized -dense mature CT should be debrided for vasularity -margins of chronic wounds should be excised to remove thin layers of epitheliium |
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how long should flap be?
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as long or longer than wound
a relaxing incision should be 1.5x as long |
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should a flap be wider at its base or its tip?
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base!
must not be too thin wider is better: increases chance that cutaneous artery may be included at its base |
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what are the pros and cons of including underlying panniculus musculature in subdermal flap?
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not including it:
reduces metabolic requirements of the flap reduces demands on the subdermal plexus often the underlying musculature is too close to separate the skin from it most commonly "composite" flaps include underlying musculature, oral mucosa, or both |
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what are the classes of skin flaps when classified by the way they are moved?
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advancement flaps: shift skin without rotation
rotating flaps: include rotation, transposition, and interpolation flaps. they pivot around a point central to their base |
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what is a rotation flap?
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semicircular, cover a triangular defect along one border
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what is a transposition flap
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shares a common border with the defect, however , the flap is rotated across intact skin to reach an adjacent defect. bring in new skin to the defect, so are more versatile than advancement flaps
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what is an interpolation flap
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lacks a common border with the recipient bed. must be tubed or incorporated into a "bridging incision" betwn the recipient and donor beds.
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what is the difference between bipedicle and single pedicle flaps
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single pedicle: two incisions perpendicular to the wound
bipedicle: incision parallel to the wound |
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single pedicle
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bipedicle flap
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guidelines for bipedicle flap length/width
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width of flap should be roughly width of the wound
total length should be no more than twice the width of the flap base |
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how do you construct a rotation flap?
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curved incision is begun at a point adjacent to the shortest side of the triangular wound.
incision is gradually lengthened until it is of sufficient length bilateral rotation flaps can be used to cover rectangular defects |
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guidelines for length and width of transposition flaps
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as wide as the defect
length = distance betwn pivot point of the flap and the most distant point of the defect |
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name some common composite flaps
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myocutaneous axial pattern flaps like lattisimus dorsi flap
mucocutaneous flaps like labial advancement flap, lip to lid flap for lower eyelid |
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transposition flap pic
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elbow fold flap
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preservation of 1 of 4 attachments preserves blood supply
if lateral thoracic artery is included, its actually an axial pattern flap |
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flank fold flap pic.
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name 5 examples of subdermal plexus flaps
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skin fold flaps
scrotal flap peripreputial flap phalangeal fillet labial flaps lip to lid flap |
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describe the phalangeal fillet
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skin over phalanx is incised to produce flap, digit is amputated so that skin can be rotated to deal with metatarsal/metacarpal pad.
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important vessels involved in labial flaps
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inferior and superior labial arteries
angularis oris |
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what is a lip to lid flap. what vessel is important
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angularis oris a+v
uses the junction of the caudal lip skin and attched labial mucosa to replace the lower eyelid |
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how are defects of the lateral lid margin best addressed?
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by local rotation flap from temporal region
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major comps of subdermal plexus flaps?
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infection
necrosis dehiscence devascularization seroma without adherence to underlying sq:more dead space, tension concentrates around edges. suture pull through, relaice completely of subdermal plexus cuz no angiogenesis from deeper tissues. |
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what is the morbididty of flap procedures post radiation therapy?
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dehiscence: 62%
flap necrosis: 35% infection: 27% risk os highest when radiation performed BEFORE flap because damage to local fibroblasts and vessels |
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what happens to devitalized skin?
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either liquefactive necrosis or eschar
eshcar ay not seperate from underlying tissue for up to 4 weeks necrotic skin should be debrided asap |
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what does hyperbaric O2 therapy do for flaps?
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improves survival by presenting tissue with hyperoxygenated blood that stimulates fibroblasts and enhances tissue revascularization
a review of small animals studies showed small but consistent improvement with hyperbaric treatment |
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what are the two main direct distant flaps?
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single pedicle flap (hinge flap)
bipedicle flap (pouch flap) flap is developed from lateral thoracic or abdominal skin, and sutured to limb defect donor bed is managed as an open wound until the skin has healed to the recipient bed and limb can be cut down they are suprisingly successful but incredibly time consuming and expensive, so generally axial pattern flaps are preferred. |
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what is a indirect/delayed tube flap and when is it used?
what are the guidelines regarding size in development? |
used to transfer skin to a distant site when there is no immediate need to cover an area
two parallel incisions are made in mobile ski. the flap is rolled into a tube and ends are sutured together. the underliying defect is undermined and closed primarily. 3 weeks later one end of the tube is severed and advaced into recipient bed. 3 weeks later other end os severed and advanced length and width should be at least 25% greater than that needed for recipient bed to account for flap shrinkage axial pattern flaps have basically replaced the need for these |
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how are tubed flaps moved in small animals
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caterpillaring
waltzing tumbling |