Chapter 1: Wound healing

Question 1

What are the three types of closure and give examples?

Answer 1

• Wound closure is divided into primary, secondary and tertiary (delayed primary) intention.

Primary intention–>Surgical wound that is sutured and closed in OR
Secondary intention–> Abscess that is drained and packed.
Tertiary intention–> Fasciotomy wound closed 1 week after operation.

Question 2

What are the phases of wound healing? which cells are most important in the first two phases?

Answer 2

• These include inflammatory phase (hemostasis and inflammation), proliferative phase, maturation phase (wound contraction and remodeling of ECM).

Inflammatory phase–> Macrophages
Proliferative phase–> Fibroblasts

Question 3

What are the primary mechanisms of wound healing impairement? what are the systemic and local conditions?

Answer 3

Hypoxia, bacterial colonization, ischemia-reperfusion injury, altered cellular response to stress, and defects in collagen production are the primary mechanism of wound healing impairment. Specific causes include;

Systemic conditions–> Diabetes mellitus, PVD, smoking, malnutrition, immunosuppression and age
Local factors–> Pressure-induced ischemia, infection and radiation

Question 4

What conditions lead to exuberant wound healing? what are their main characteristics?

Answer 4

• Hypertrophic scars and keloids

Hypertrophic scars:

• Remain within the boundary of the original injury
• Regress spontaneously
• Rarely recur after surgical excision

Keloids

• Extend beyond the boundaries of the original injury
• Continue to grow over time
• Commonly recur after excision
• Are present for a minimum of 1 year
• Common in black people between 10-30 years