Skin Flaps

Question 1

Define a skin flap.

Answer 1

Blood flow is maintained or immediately re-established when skin segment is moved to new position.

Question 2

Define a skin graft.

Answer 2

Blood supply is severed and new vessels must grow in from recipient site

Question 3

What are the 2 general categories of skin flaps?

Answer 3

Type of blood supply

Distance from wound

Question 4

What are 3 types of blood supply?

Answer 4

Subdermal plexus
Axial pattern flap
Revascularized

Question 5

What are the 2 types of distance from wound?

Answer 5

Local

Distant

Question 6

Where does the subdermal plexus originate?

Answer 6

In the cutaneous trunci muscle

Question 7

Where is the blood supply usually based in a local flap?

Answer 7

Based in the subdermal plexus

Question 8

What 2 types of local flap do not rotate around a pivot point

Answer 8

Single pedicle advancement flap

H-plasty (two single pedicle flaps advanced together)

Question 9

What 2 types of local flap move about a pivot point?

Answer 9

Rotation flaps

Transposition flaps

Question 10

What are 2 reasons for using a single pedicle flap?

Answer 10

When donor skin is available only on one side

When simple undermining and advancement would cause too much tension or distortion

Question 11

How is a rotation flap made?

Answer 11

Arc incision ~2.5x width of defect, undermine flap and rotate to cover wound.

Question 12

Why would you keep your skin flap thick?

Answer 12

To minimize destruction of blood supply

Question 13

Why should you try to avoid tacking down the skin flap?

Answer 13

Because you may accidentally ligate the blood supply

Question 14

What can you do to try and prevent dog ears?

Answer 14

Space suture further apart on the long side and closer together on the short side

Question 15

How do you manage dog ears?

Answer 15

Small ones resolve during healing

Larger ones should be removed

Question 16

How do you remove a larger dog ear?

Answer 16

At end of incision with dog ear, extend incision slightly and remove small flap from ONE side to suture the rest down together.

Question 17

When might you use multiple rotation flaps?

Answer 17

If you can’t close the wound with just one.

Remember the cat butt picture.

Question 18

What is a transposition flap?

Answer 18

3-sided flap from a different axis from the wound

Question 19

What do you need to remember about the length of a transposition flap?

Answer 19

The greater the angle from the wound, the shorter the flap length becomes

Question 20

How wide can you make a transposition flap and still have decent blood flow?

Answer 20

The flap can be 3x the width of the wound

Question 21

What is the most common degree of rotation with a transposition flap?

Answer 21

60-90 degrees

Question 22

What happens if your transposition flap is too short?

Answer 22

Too much tension through the middle of the flap and can interfere with blood supply.

Question 23

Why should you always draw out the skin flap before cutting?

Answer 23

So you don’t mess it up

Question 24

If you have a patient undergoing concurrent radiation or other therapies, why should you leave the sutures in longer?

Answer 24

Because the treatments will prolong healing

Question 25

What is an axial pattern flap?

Answer 25

Transposition flaps that incorporate a direct cutaneous artery and vein

Question 26

What is a benefit to using an axial pattern flap?

Answer 26

You can make the flap much longer because you're bringing direct blood supply with it.

Question 27

What are 2 major axial pattern flaps that you can use?

Answer 27

Thoracodorsal | Caudal Superficial Epigastric

Question 28

Where does the thoracodorsal artery run?

Answer 28

Exits just caudal to the shoulder and follows parallel to the spine of the scapula. NOTE: limb must be in neutral position

Question 29

How far can the thoracodorsal axial flap cover?

Answer 29

Mid-antebrachium in dogs with normal conformation. | To carpus and beyond in cats and short-legged dogs.

Question 30

How far can the caudal superficial epigastric axial flap cover?

Answer 30

Mid-tibial in female dogs with normal conformation (male dogs less likely) Hock in cats and short-legged dogs (especially in females)

Question 31

What is 1 pro and 1 con to an ipsilateral caudal superficial epigastric axial flap in a female?

Answer 31

Pro: Increases distance flap can extend Con: Increases risk of kinking vessels

Question 32

What is 1 pro and 1 con to an contralateral caudal superficial epigastric axial flap in a female?

Answer 32

Pro: Less risk of kinking vessels Con: Shorter distance

Question 33

What does it mean to create a "bridging incision"?

Answer 33

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)

Question 34

What does it mean to "tube the flap"?

Answer 34

Avoids a bridging incision by suture the extra tissue into a tube fir removal later (usually 14-21 days)

Question 35

What are 5 complications of a skin flap?

Answer 35

``` Flap edema Seroma Infection Partial dehiscence Vessel thrombosis with flap loss ```

Question 36

How do we deal with flap edema?

Answer 36

Usually just have owner deal with it. Vessels are just confused and figuring shit out.

Question 37

How do we deal with a seroma?

Answer 37

Put a drain in it.

Question 38

What flap complication do we worry about the most?

Answer 38

Vessel thrombosis because we can lose the entire flap.

Question 39

What 4 things can you do to manage a compromised flap?

Answer 39

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)

Question 40

What are 3 ways to replace skin on the distal extremities?

Answer 40

Revascularized flap Skin graft Distant flap

Question 41

What are 2 types of distant flap?

Answer 41

Pouch flap | Single pedicle direct flap

Question 42

What is the difference between a pouch flap and a single pedicle direct flap?

Answer 42

One blood supply (single pedicle) vs. two (pouch flap)

Question 43

What 2 things must you make sure the patient can/will do before you opt for a distant flap?

Answer 43

Make sure patient can get up on 3 limbs | Make sure it will tolerate having limb bandaged