Wound Healing Mechanisms

Wound Healing Mechanisms

• Phases of wound healing:
  1. Inflammation (0-4 days): Hemostasis, platelet activation, and inflammation
  2. Debridement (4-7 days): Removal of dead tissue and debris
  3. Proliferation (7-14 days): Granulation tissue formation, angiogenesis, and collagen deposition
  4. Remodeling (14+ days): Tissue reorganization and strengthening
• Cellular and molecular mechanisms:
  • Platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-β) promote wound healing
  • Fibroblasts and keratinocytes play key roles in collagen synthesis and epithelialization

Surgical Site Complications

• Types of complications:
  • Infection
  • Dehiscence
  • Seroma
  • Hematoma
  • Wound necrosis
• Risk factors:
  • Age
  • Diabetes
  • Obesity
  • Smoking
  • Steroid use
  • Malnutrition

Wound Infection Classification

• Wound infection classification:
  • Clean: No infection, no inflammation
  • Clean-contaminated: Infection, but no inflammation
  • Contaminated: Infection, with inflammation
  • Dirty: Gross infection, with pus or necrotic tissue

Surgical Wound Classification According to Their Cleanness

• Classification system:
  • Clean wounds: No break in sterile technique, no entry into hollow viscus, and no inflammation
  • Clean-contaminated wounds: Break in sterile technique, but no inflammation or infection
  • Contaminated wounds: Inflammation or infection, but no gross pus or necrotic tissue
  • Dirty wounds: Gross infection, with pus or necrotic tissue
• Factors influencing wound classification:
  • Type of surgery
  • Presence of inflammation or infection
  • Break in sterile technique
  • Entry into hollow viscus

Wound Healing Mechanisms

• Wound healing process consists of four phases: inflammation, debridement, proliferation, and remodeling.
• Inflammation phase lasts 0-4 days and involves hemostasis, platelet activation, and inflammation.
• Debridement phase lasts 4-7 days and involves removal of dead tissue and debris.
• Proliferation phase lasts 7-14 days and involves granulation tissue formation, angiogenesis, and collagen deposition.
• Remodeling phase lasts 14+ days and involves tissue reorganization and strengthening.
• Platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-β) promote wound healing.
• Fibroblasts play a key role in collagen synthesis, while keratinocytes play a key role in epithelialization.

Surgical Site Complications

• Infection is a type of surgical site complication.
• Dehiscence is a type of surgical site complication.
• Seroma is a type of surgical site complication.
• Hematoma is a type of surgical site complication.
• Wound necrosis is a type of surgical site complication.
• Age is a risk factor for surgical site complications.
• Diabetes is a risk factor for surgical site complications.
• Obesity is a risk factor for surgical site complications.
• Smoking is a risk factor for surgical site complications.
• Steroid use is a risk factor for surgical site complications.
• Malnutrition is a risk factor for surgical site complications.

Wound Infection Classification

• Wounds can be classified as clean, clean-contaminated, contaminated, or dirty based on the presence of infection and inflammation.
• Clean wounds have no infection and no inflammation.
• Clean-contaminated wounds have infection, but no inflammation.
• Contaminated wounds have infection and inflammation.
• Dirty wounds have gross infection, with pus or necrotic tissue.

Surgical Wound Classification According to Their Cleanness

• Surgical wounds can be classified as clean, clean-contaminated, contaminated, or dirty based on the presence of infection and inflammation.
• Clean wounds have no break in sterile technique, no entry into hollow viscus, and no inflammation.
• Clean-contaminated wounds have a break in sterile technique, but no inflammation or infection.
• Contaminated wounds have inflammation or infection, but no gross pus or necrotic tissue.
• Dirty wounds have gross infection, with pus or necrotic tissue.
• Type of surgery influences wound classification.
• Presence of inflammation or infection influences wound classification.
• Break in sterile technique influences wound classification.
• Entry into hollow viscus influences wound classification.