Stages of Wound Healing

Question 1

inflammatory phase

Answer 1

• 1-10 days
• inflammation is the immune system’s initial response to a wound
• temporary repair mechanisms rapidly re-establish hemostasis through platelet activation and the clotting cascade
• debris and necrotic tissue are removed and bacteria are killed by mast cells, neutrophils, and leukocytes
• this establishes a clean wound bed which signals tissue restoration and permanent repair processes to begin
• reepithelialization typically begins within 24 hours at the wound borders, though visible signs are usually not observe earlier than three days after injury

Question 2

Proliferative phase

Answer 2

• 3-21 days
• formation of new tissue signals the beginning of the proliferative phase
• capillary buds and granulation tissue begin to fill the wound bed creating a support structure for the migration of epithelial cells
• keratinocytes, endothelial cells, and fibroblasts are active and the collagen matrix is formed
• skin integrity is restored in the proliferative phase with wound closure occurring through epithelialization and wound contraction

Question 3

maturation (remodeling) phase

Answer 3

• 7 days to 2 years
• initiated when granulation tissue and epithelial differentiation begin to appear in the wound bed
• mechanisms of fiber reorganization and contraction shrink and thin the scar
• immature scar will appear red, raised, and rigid while mature scar will appear pale, flat, and pliable
• scar tissue is remodeled and strengthened through the processes of collagen lysis and synthesis
• newly repaired tissues have approximately 15% of pre-injury tensile integrity and should be protected to prevent reinjury
• tensile integrity may increase to as much as 80% of the pre-injury strength
• hypertrophic scarring can significantly impact maturation phase progression
• burn without hypertrophic scarring will mature in 4-8 weeks,
• burns with hypertrophic scarring may require up to 2 years to reach maturity

Question 4

primary intention

Answer 4

• most commonly occurs in acute wounds with minimal tissue loss
• smooth clean edges are reapproximated and closed with sutures, staples or adhesives to facilitate re-epithelialization
• superficial partial-thickness wounds, such as abrasions or blisters also heal by primary intention with epithelial migration over the wound bed frequently completed within 72 hours
• minimal scarring and heal quickly in an uncomplicated and orderly progression
• surgical incision, laceration, puncture, and superficial and partial-thickness wounds

Question 5

secondary intention

Answer 5

• permits wounds to close on their own without superficial closure
• significant tissue loss or necrosis, irregular or nonviable wound margins that cannot be reapproximated, infection or debris contamination typically heal by secondary intention
• often associated with pathology such as diabetes, ischemic conditions, pressure damage, or inflammatory disease
• a layer of granulation tissue will gradually fill the wound bed to the level of the surrounding skin, with closure occurring by wound contraction and scar formation
• requires ongoing wound care and have significantly larger scars than those healing by primary intention
• neuropathic, arterial, venous or pressure ulcers, most full-thickness wounds, and chronically inflamed wounds

Question 6

tertiary intention

Answer 6

• delayed primary intention healing
• wounds at risk for developing complications, such as sepsis or dehiscence , may be temporarily left open
• once risk factors have been alleviated, the wound is closed by the usual primary intention methods