Skin Flaps Flashcards
Define a skin flap.
Blood flow is maintained or immediately re-established when skin segment is moved to new position.
Define a skin graft.
Blood supply is severed and new vessels must grow in from recipient site
What are the 2 general categories of skin flaps?
Type of blood supply
Distance from wound
What are 3 types of blood supply?
Subdermal plexus
Axial pattern flap
Revascularized
What are the 2 types of distance from wound?
Local
Distant
Where does the subdermal plexus originate?
In the cutaneous trunci muscle
Where is the blood supply usually based in a local flap?
Based in the subdermal plexus
What 2 types of local flap do not rotate around a pivot point
Single pedicle advancement flap
H-plasty (two single pedicle flaps advanced together)
What 2 types of local flap move about a pivot point?
Rotation flaps
Transposition flaps
What are 2 reasons for using a single pedicle flap?
When donor skin is available only on one side
When simple undermining and advancement would cause too much tension or distortion
How is a rotation flap made?
Arc incision ~2.5x width of defect, undermine flap and rotate to cover wound.
Why would you keep your skin flap thick?
To minimize destruction of blood supply
Why should you try to avoid tacking down the skin flap?
Because you may accidentally ligate the blood supply
What can you do to try and prevent dog ears?
Space suture further apart on the long side and closer together on the short side
How do you manage dog ears?
Small ones resolve during healing
Larger ones should be removed
How do you remove a larger dog ear?
At end of incision with dog ear, extend incision slightly and remove small flap from ONE side to suture the rest down together.
When might you use multiple rotation flaps?
If you can’t close the wound with just one.
Remember the cat butt picture.
What is a transposition flap?
3-sided flap from a different axis from the wound
What do you need to remember about the length of a transposition flap?
The greater the angle from the wound, the shorter the flap length becomes
How wide can you make a transposition flap and still have decent blood flow?
The flap can be 3x the width of the wound
What is the most common degree of rotation with a transposition flap?
60-90 degrees
What happens if your transposition flap is too short?
Too much tension through the middle of the flap and can interfere with blood supply.
Why should you always draw out the skin flap before cutting?
So you don’t mess it up
If you have a patient undergoing concurrent radiation or other therapies, why should you leave the sutures in longer?
Because the treatments will prolong healing
What is an axial pattern flap?
Transposition flaps that incorporate a direct cutaneous artery and vein
What is a benefit to using an axial pattern flap?
You can make the flap much longer because you’re bringing direct blood supply with it.
What are 2 major axial pattern flaps that you can use?
Thoracodorsal
Caudal Superficial Epigastric
Where does the thoracodorsal artery run?
Exits just caudal to the shoulder and follows parallel to the spine of the scapula.
NOTE: limb must be in neutral position
How far can the thoracodorsal axial flap cover?
Mid-antebrachium in dogs with normal conformation.
To carpus and beyond in cats and short-legged dogs.
How far can the caudal superficial epigastric axial flap cover?
Mid-tibial in female dogs with normal conformation (male dogs less likely)
Hock in cats and short-legged dogs (especially in females)
What is 1 pro and 1 con to an ipsilateral caudal superficial epigastric axial flap in a female?
Pro: Increases distance flap can extend
Con: Increases risk of kinking vessels
What is 1 pro and 1 con to an contralateral caudal superficial epigastric axial flap in a female?
Pro: Less risk of kinking vessels
Con: Shorter distance
What does it mean to create a “bridging incision”?
Makes a communication between the base of the flap and the wound to avoid a second procedure (as you would have if you had to make a tube)
What does it mean to “tube the flap”?
Avoids a bridging incision by suture the extra tissue into a tube fir removal later (usually 14-21 days)
What are 5 complications of a skin flap?
Flap edema Seroma Infection Partial dehiscence Vessel thrombosis with flap loss
How do we deal with flap edema?
Usually just have owner deal with it. Vessels are just confused and figuring shit out.
How do we deal with a seroma?
Put a drain in it.
What flap complication do we worry about the most?
Vessel thrombosis because we can lose the entire flap.
What 4 things can you do to manage a compromised flap?
Assess vascular integrity
Use vasoactive drugs
Hyperbaric oxygen
Leaches (can detect venous compromise because they won’t feed on arterial blood so can be used diagnostically)
What are 3 ways to replace skin on the distal extremities?
Revascularized flap
Skin graft
Distant flap
What are 2 types of distant flap?
Pouch flap
Single pedicle direct flap
What is the difference between a pouch flap and a single pedicle direct flap?
One blood supply (single pedicle) vs. two (pouch flap)
What 2 things must you make sure the patient can/will do before you opt for a distant flap?
Make sure patient can get up on 3 limbs
Make sure it will tolerate having limb bandaged
