Wound Closure

Question 1

Which layer of muscle must always be trasnected below when skin graftin?

Answer 1

Cutaneous trunci as contains deep subdermal plexus from direct cutaneous arteries and veins

Question 2

Which artery supplies the skin overlying the shoulder in the dog and cat?

Answer 2

Thoracodorsal artery

Question 3

What is an area of skin supplied by one direct cutaneous a. called?

Answer 3

Angiozone

Question 4

What factors may impact skin tension?

Answer 4

• regional differences
• breed
• species
• disease influence (eg. hyperadrenocorticism and Ehlos-Danois syndrome -> fragile skin)

Question 5

What are the 5 potential wound closure mechanisms?

Answer 5

• 1* closure
• delayed 1* closure
• 2* closure
• contraction and epithelialisation
• reonstruction (this lecture)

Question 6

What 3 ways may dead space be managed? What must you be aware of?

Answer 6

• suturing
• bandaging
• drains
  > be aware of compromising blood supply with sutures, bandages etc.

Question 7

Is 2* closure a valid way to close a wound?

Answer 7

Yes, most wounds would eventually close up with granulatin tissue etc.
1* closure used to speed up process if owner impatient etc.

Question 8

5 options to v wound tension

Answer 8

1. maximise available skin (patient position)
2. change local skin tension (geometric patterns)
3. mobilise local skin (undermining deep to cutaneous trunci)
4. increase local skin (stretching by pre-suturing or stretchers)
5. remove tension (relaxing incision)

Question 9

What is a v-Y plasty used for?

Answer 9

U shaped flaps

Question 10

What is a Z plasty used for?

Answer 10

changing local skin tension - make Z incision with middle line parallel to line of tension (ie. across wound)

Question 11

How may skin be stretched?

Answer 11

• velro or elastic straps

- re-adjust tension q6-8hrs for 2-4d

Question 12

What are local (random) subdermal plexus flaps? SDPF?

Answer 12

Cutting section of skin near wound to place over wound.

• advancement
• transposition/rotation around a central point
• pie shaped incision rotated around centre

Question 13

What are distant SDPFs? What are the requirements of the wound site? When are these not indicated?

Answer 13

Full thickness grafts from distant sites - usually used for distal limbs
- fresh wound
- healthy granulation tissue 
- omentalised wound 
> not indicated for 
- exposed bone, tendon or ligament
- infection or movement
- chronic granulation tissue

Question 14

What are axial pattern flaps?

Answer 14

Flaps based on direct cutaneous artery position and angiozones

Question 15

Where does the thoracodorsal artery arise?

Answer 15

Depression between deltoid and triceps

Question 16

Can donor skin be folded over existing skin to make a bridge?

Answer 16

Yes, top layer will become reducndant and must be removed

Question 17

Where does the caudal superficial epigastric artery run?

Answer 17

Arises from inguinal ring and runs along the ventral abdomen under mammary glands.

Question 18

How many nipples do cats and dogs have? How many of them can be used in a caudal superficial epigastric axial pattern flap?

Answer 18

dogs 10
cats 8
all but most cranial nipple can be transplanted

Question 19

What should be remembered when performing skin grafting?

Answer 19

Hair will not grow same direction - cat may groom back

Question 20

What is the reverse saphenous conduit?

Answer 20

• medial crus (hindleg)

- reversal of flow through dorsal metatarsal and plantar arteries via the saphenous

Question 21

What are compound or composite flaps?

Answer 21

• myocutaneous latissimus dorsi flap for thoracic wall reconstruction

Question 22

What is a direct distant subdermal plexus flap?

Answer 22

• distal limb wound sutured into flap on side of thorax

- requires 2 anaesthetics

Question 23

How do free grafts differ from subdermal plexus flaps?

Answer 23

Should be as thin as possible - cutaneous trunci not wanted

Question 24

What types of free skin graft are possible?

Answer 24

• split v full thickness
• full sheet or meshed
• pinch or punch
• line grafting

Question 25

What is homograft survival dependent upon?

Answer 25

• adhesion
• plasmatic imbibition
• vascular ingrowth (inosculation)
• maturation

Question 26

When are hand meshed grafts useful?

Answer 26

undulating or uneven surfaces

Question 27

What is required for 24hours after a free skin graft?

Answer 27

rigid dressing to prevent shear forces

Question 28

eg. of a passive dressing? pros and cons?

Answer 28

Silicone mesh

• low/non-absorbant
• expensive
• soft
• easy to apply
• stick to dry skin
• need 2* absorbant layer
• reusable

Question 29

What should be done if the wound reconstruction fails?

Answer 29

manage as open wounds until they are healthy enough to undergo another reconstruction