Wound Healing

Question 1

Primary intention

Answer 1

Apposition of wound edges; all layers closed, minimal scar formation

Question 2

Secondary intention

Answer 2

Deep layers closed but superficial layers left open; appropriate in cases of infection, excessive trauma, tissue loss or imprecise approximation of tissue

Question 3

Tertiary intention

Answer 3

Delayed primary closure

Question 4

Wound classes

Answer 4

Clean
Clean/contaminated
Contaminated
Dirty

Question 5

Stage 1 of wound healing

Answer 5

Haematoma: wound filled with blood, activation of clotting cascade, blood clotting, wound sealed from dehydration and infection

Question 6

Stage 2 of wound healing

Answer 6

Inflammation: damaged endothelial cells release cytokines, histamine, serotonin and kinins cause vessel contraction (decreased blood loss), expression of integrands of circulating lymphocytes, and acts as chemotactic factors for neutrophils (most abundant cells in 24hrs)

Question 7

Stage 3 of wound healing

Answer 7

Proliferation: release of cytokines which stimulate macrophage migration; involved in matrix synthesis, further cell activation and angiogenesis

Question 8

When does greatest increase in wound strength occur?

Answer 8

Proliferation phase

Question 9

Wound strength %’s?

Answer 9

1% at 1 week
20% at 3 weeks
80% at 3 months

Question 10

Stage 4 of wound healing

Answer 10

Maturation: lasts from 3 weeks to 9 months
Collagen III converted to collagen I
Tensile strength gradually increases

Question 11

Hypertrophic vs. keloid scar

Answer 11

Overgrowth of scar tissue but in keloid it goes beyond the boundaries of the original scar

Question 12

Which cells cause wound contraction?

Answer 12

Myofibroblasts

Question 13

Peripheral nerve damage leads to….

Answer 13

Wallarian degeneration

Question 14

What is Wallarian degeneration?

Answer 14

• Axonoplasmic condensation
• Myelin degeneration (& clearance by Schwann cells)
• Perineurium breakdown

Question 15

What happens during peripheral nerve regeneration?

Answer 15

• Starts 24 hours after damage
• Chromatolysis
• Tubulin production
• Proximally cut end forms growth cone
• Branches enter scar and find endoneurial tube
• Distally, Schwann cells remyelinate advancing axons

Question 16

Why does foetal wound healing not leave a scar?

Answer 16

REGENERATION not repair!

Question 17

Surgical wound infection

Answer 17

Incisional infection identified by purulent or culture positive drainage isolated from any structure above fascia in proximity to initial wound

Question 18

Local factors affecting wound healing

Answer 18

Tissue handling
Denervation
Infection
Prior radiation
Oxygenation levels
Local ischaemia
Covering

Question 19

Patient/general factors affecting wound healing

Answer 19

Age
Comorbidities
Nutritional status
Immunosuppressant/steroid use
Vitamin deficiencies
Smoking