Reconstructive techniques 1 + 2

Question 1

Name the two scissors used for sharp and blunt dissection NOT for cutting suture material

Answer 1

Mayo
Metzenbaum

Question 2

Name the two needle holders

Answer 2

Mayo-Hegar or Olsen-Hegar

Question 3

Whenever you make a surgical incision or close a wound what are your aims?

Answer 3

• Square skin edges: when cutting skin, hold the scalpel blade at 90degrees to the skin. Angled cuts cause angled skin edges that tend to overlap when sutured.
• Accurate tissue apposition: for optimal healing the dermis on each side of the wound needs to be in contact.
• Slight eversion of the wound edges: this helps to appose the dermis. Take a larger bite of the deep dermis with your suture needle than of the superficial layers of the skin.

Question 4

What should you do if you cant close a wound without tension using appositional sutures?

Answer 4

Assess the elasticity and mobility of the skin around the wound and use the simplest, quickest and least expensive suitable tension-relieving technique

Question 5

Describe undermining and advancing skin

Answer 5

Sharp or blunt undermining allows you to stretch skin to close defects

Question 6

What should you avoid when undermining and advancing skin?

Answer 6

Avoid injury to the subdermal plexus and preserve direct cutaneous arteries by undermining deep to the panniculus muscle (where present) or in the loose areolar fascia deep to the dermis in areas without panniculus.

Question 7

In which parts of the body is undermining most successful?

Answer 7

neck, trunk and abdomen

Question 8

What are the advantages of walking sutures?

Answer 8

Can advance undermined skin towards a defect, spread tension evenly and eliminate dead space

Question 9

Name some tension relieving suture patterns

Answer 9

Vertical mattress
Horizontal mattress
Far-near-near-far
Far-far-near-near

Question 10

Describe the use of relaxing/releasing incisions

Answer 10

• Allow the intervening skin to close the primary defect
• Useful when the primary defect overlies a vital structure (nerve, tendon, major blood vessel)

Question 11

Closure of fusiform (one side is straight one is rounded) or elliptical incisions can sometimes form “dog-ears” at the end of the wound if the two sides are different lengths, how can you correct this (2 methods)?

Answer 11

1. Suturing the wound while spacing sutures further apart on the longer side
2. Suturing the wound by progressively placing sutures halfway along each section of the wound

Question 12

How should you suture triangular, rectangular or square defects?

Answer 12

For these, start to suture at the corners and proceed to the centre

Question 13

How should you suture circular defects?

Answer 13

Either convert the defect into a linear or curvilinear closure by making it into a fusiform defect, perform a 3-point closure or create flaps at each end of the circle and advance them to close the defect.

Question 14

What are skin flaps

Answer 14

Sections of skin with an intact vascular supply that are moved to close wounds

Question 15

When do skin flaps have the best cosmetic results?

Answer 15

If the hair of the flap has similar density and colour to the recipient site

Question 16

Describe the steps involved in planning skin flaps

Answer 16

• Suitable donor sites: ample skin and without excessive tension or movement
• Appropriate flap for the wound, initially larger than the defect you wish to cover
• Avoid narrow base to flap
• Undermine below the panniculus
• Use fine suture material with initial tacking sutures to ensure that flap conforms well to the recipient bed with minimal, even tension
• Ensure the recipient bed is either a fresh surgical wound or a healthy granulation tissue bed free of infection, contamination and necrotic tissue

Question 17

Where do subdermal plexus flaps get their blood supply from?

Answer 17

The subdermal plexus and attenuated branches of distant direct cutaneous arteries

Question 18

How are subdermal plexus flaps created?

Answer 18

By undermining skin deep to the panniculus muscle layer (or dermis in areas with no panniculus).

Question 19

Describe the several types of subdermal plexus flap - based on the shape of the recipient wound bed and the available skin

Answer 19

• Rotation flaps: used for closing triangular defects.
• Transposition flaps: rectangular flaps rotated into place over a wound.
• Interpolation flaps: similar to transposition flaps but they do not share a common border with the wound so a section of the flap must cross the skin between the donor and recipient beds, usually achieved by creating a bridging incision.
• Advancement flaps: unipedicle or bipedicle flaps that use the elasticity of the skin to advance tissue over the recipient bed

Question 20

What are axial pattern skin flaps?

Answer 20

• These are flaps incorporating a specific, large direct cutaneous artery and vein.
• They can include large areas of skin and are similar in cats and dogs.

Question 21

For what reasons do skin flaps fail?

Answer 21

• Arterial/venous occlusion caused by thrombi, torsion or stretching of direct cutaneous vessels
• Elevated interstitial pressure due to excessive tension causing reduced circulation and necrosis
• Pressure on the flap from underlying haematomas/seromas or tight dressings reducing blood flow
• Infection (especially if blood supply is compromised)

Question 22

How can skin flap failure be prevented?

Answer 22

Atraumatic surgical technique
Strict asepsis
Meticulous haemostasias
Careful planning

Question 23

How can you subjectively assess the health of a skin flap?

Answer 23

• Colour: unreliable as successful flaps may go through red and lavender stages
• Temperature: the flap should be approximately the same temperature as the surrounding skin
• Sensation: unreliable
• Hair growth: only occurs if the flap is viable but this is of little use immediately postoperatively as hair hasn’t had time to grow by then

Question 24

How can you objectively assess the health of a skin flap?

Answer 24

• Various laboratory measurements – no clinical use
• Fluorescein dye fluorescence – non-fluorescent areas often dehisce, although the delineation between healthy and non-viable tissue may not be clear and non-fluorescent areas sometimes survive

Question 25

By what methods can you try to salvage a failing skin flap?

Answer 25

• Apply ointments to prevent desiccation
• Debride nonviable tissue
• Open wound management followed by secondary closure or development of a second flap to deal with areas of dehiscence

Question 26

What are free skin grafts?

Answer 26

Segments of skin completely detached from the donor site and transferred to a distant recipient site where a lack of skin mobility precludes local closure or flap construction e.g. on extremities.

Question 27

How do free skin grafts survive?

Answer 27

By absorbing tissue fluid from the recipient bed during the initial 48hrs after transplantation, then by developing a new blood supply from the recipient bed.

Question 28

Why are autographs generally used in small animals?

Answer 28

Cause no problems with rejection

Question 29

Describe the features of full-thickness skin grafts

Answer 29

Durable, have good hair growth and good survival rates if meshed
Prone to failure if not meshed.

Question 30

Describe the features of split-thickness skin grafts

Answer 30

More viable than full-thickness but they are less durable, hair may be absent or sparse and harvesting them is more difficult and requires special equipment.
Not indicated in cats as their skin is so thin

Question 31

What is the role of surgical drains?

Answer 31

Remove unwanted fluid from the wound and eliminate dead space

Question 32

What are the principles of surgical drain use?

Answer 32

• Aseptically prepare the skin before placing a drain
• Drains cause a foreign body reaction that increases the risk of infection
• Cover the drain exit with a sterile absorbent dressing and regularly change it before it is saturated
• Do not place the drain along the length of or exiting from the suture line as this may cause dehiscence.

Question 33

Penrose drains are an example of?

Answer 33

Passive drains

Question 34

Describe the features of passive drains

Answer 34

• Rely on gravity and capillary action to draw fluid from the wound
• Their efficiency is proportional to their surface area

Question 35

Describe the features of active drains

Answer 35

These apply negative pressure using continuous or intermittent suction to evacuate fluid and collapse dead space
Intermittent suction is applied at least every 6 hours.
Constant suction is better than intermittent

Question 36

When should a drain be removed?

Answer 36

When a consistently small volume of serosanguineous fluid is being produced