10 – Skin Flaps

Question 1

What are flaps and grafts used for?

Answer 1

• Closing skin defects
  o Especially situations where the wound will NOT heal completely or well by second intention
• Close wounds without undue tension

Question 2

Flaps

Answer 2

• Maintain connection to the donor site at one end (at least)
• Depend upon blood supply coming from the donor area to survive
• *need to maintain blood supply from the donor site limits length and positioning of flap

Question 3

Grafts

Answer 3

• Reserved for tissue removed entirely from the donor site and placed into the recipient site
• May be either vascularized (requires microsurgery) OR not (more common in vet med)
• Ex. go to in horses as they do not have much extra skin

Question 4

What are the different types of flaps?

Answer 4

• Subdermal plexus flaps
  o Rotation flaps
  o Single pedicle advancement flaps
• Axial pattern flaps
  o Regular transposition flaps
  o Island flaps: more mobile

Question 5

Subdermal plexus flaps (also called random pattern flaps)

Answer 5

• Nourished by subdermal plexus
  o *keep cutaneous trunci with the skin
• In general: should NOT be more than twice as long as they are wide
• Base should be WIDER than the tip

Question 6

Rotation flap

Answer 6

• Arc needs to be at least 3x length of the defect
• Undermine the flap
• *most powerful of subdermal plexus flaps
• Relies on general stretchiness of a large flap of skin

Question 7

Single pedicle advancement flaps

Answer 7

• Likely least useful flap
• Limited by tension and direction
• *want flap to be perpendicular to lines of tension

Question 8

Transposition flap

Answer 8

• Instead of advancing, it is rotating
• Chose an area where you can pinch the skin and you will be able to get a primary closure

Question 9

Skin fold flaps

Answer 9

• Redundant tissue in inguinal, axillary region
• Transposed to adjacent thoracic or abdominal wall or limb
• Ex. flank fold flaps, axial fold flaps

Question 10

Phalangeal fillet

Answer 10

• Sacrifice a toe and use it to make up the carpal pad
  o Incision on palmar side of toe and remove bones (keep blood supply)
• *form of axial pattern flap: have preserved the artery

Question 11

Axial pattern flaps

Answer 11

• Contain a cutaneous artery
  o Come out of a known location=we can guess where they will be
• Generally transpositional flaps (via bridging incisions, or by tubing middle portion)
  o Can be dissected as ‘island flaps’
• Can be transposed up to 180 degrees
• Robust closure for high motion/high pressure areas
• Uncommonly used in large animals (maybe in some ponies)
• Need to be careful to avoid kinking or tension on pedicle

Question 12

Transillumination technique

Answer 12

• Hold flap up to light and can see the vessel through it

Question 13

‘island’ flaps

Answer 13

• Just an umbilical cord of vessels attached to an otherwise free flap
  o Cut skin of flap circumferentially, while leaving the cutaneous artery
• *useful for reconstruction of large wounds
• *follow angiosomes (territory fed by cutaneous arteries

Question 14

Lateral genicular axial pattern flap

Answer 14

• Useful for closing defects between stifle and tarsus

Question 15

Caudal superficial epigastric (axial pattern flap)

Answer 15

• External pudendal artery exits inguinal ring, branches into CGE
• Extends cranially along mammary chain
• Angiosome includes glands 3, 4, 5
• Can extend dissection to include gland 2
• *good for closure on medial thigh wounds

Question 16

Thoracodorsal axial pattern flap

Answer 16

• Double the distance of the spine of scapula to the caudal aspect of scapula
• *hockey stick

Question 17

Superficial brachial axial pattern flap

Answer 17

• Can go as far as the greater tubercule
• Part of olecranon and anti-brachium?