Pa Tho Physiology of Wound Healing.ppt Rao 3

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Pathophysiology of

Wound HealingDr jayneshthra rao

HTF



Wound Healing

Replacement of destroyed or lost tissueby a viable tissue

Regeneration is the replacement ofthe lost tissue by a tissue of the sametype.

Repair is replacement of the destroyedtissue by a fibrous scar.



Stages of wound healing byprimary intention

Day 1

Wound filled with blood clot.

Acute inflammation in the surroundingtissue .

Proliferation of epithelial cells.



Day 5Collagen deposition

Day 7

Sutures removed



Delayed primary Closure

Wound initially left open & later primaryclosure.² Dirty and infected traumatic wounds² Extensive tissue loss.

² High risk of infection.



Healing by 2nd intention

No formal wound closure.

Heal by granulation tissue formation.

Tissue loss / gross wound contamination.



Wound healing by 2nd intention

The process is similar to healing by primaryintention but only slower due to massive lossof tissue.

The inflammatory reaction is more intense. There is more scarring.



Wound healing by 2nd intention

Wound left open & heals largely by:

± Formation of granulation tissue.

± Contraction

Occurs in a wound with extensive loss of soft tissue.

± Severe burns.

± Abscess cavities & ulcer.

Ingrowth of granulation tissues from wound marginfollowed by accumulation extracellular matrix with laying

down of collagen).



STAGE 1

HEMOSTASIS

STAGE 2

INFLAMMATION

STAGE 3

GRANULATION

STAGE 4MATURATION



Phases of Wound Healing

Carefully regulated systemic cascade ofoverlapping processes that requirecoordinated completion of variety of cellular

activities. This process involves 4 overlapping phases.

² Hemostasis (immediate)

² Inflammation (early day 1-2, late day 2-3)

² Proliferation (day 3 to week 2)

² Remodelling & Scar maturation (1 to several weeks)



Phases of Wound Healing



Inflammatory Phase

Haematoma formation

Infiltration by neutrophils

Infiltration by macrophages



Proliferative Phase

Epidermal regrowth

Dermal repair



Remodelling Phase

Replacement of the granulation tissue by afibrous tissue

Remodelling of connective tissue to achieve

wound strength Extracellular matrix > collagen > scar



Wound Strength

After sutures are removed at oneweek, wound strength is only 10% of

unwounded skin ( Walker·s Law)

B y 3-4 months, wound strength is

about 80% of unwounded skin(Walker·s Law)



Factor That Impedes Wound

Healing Local² Inadequate blood supply

² Increase skin tension

² Poor venous drainage² Presence of foreign body

² Presence of slough or non viable tissue

² Infection

² Excess local mobility

² Underlying osteomyelitis

² Malignant transformation (Marjolin·s ulcer)



Factor That Impedes Wound

Healing Systemic² Advancing age and general immobility

² Obesity

² Malnutrition² Deficiency in protein and vitamins

² Systemic malignancy and terminal illness

² Anemia

² Chemotherapy/ Radiotherapy

² Immunosuppresion drugs (corticosteroid)

² Organ failures.



Abnormal Wound Healing

Non healing wound

² Chronic wound which normal process of healing is

disrupted at one or more points.² Predisposing factors:

Changes in the profile and activities of the cells

Alteration in the composition ECM

Failure of epithilialization

Presence of free radicals and microorganism.



Abnormal Wound Healing

Excessive wound healing² Hypertrophied scar:

wound crosses tension line

Areas of increase tension & movement in skin.

Deep dermal burns

Wounds heal by secondary intention ( >3 weeks)

² Keloids Do not have specific cause although genetic

predisposition is implicated



Hypertrophic scar

Excessive build up of scar tissue confined tothe initial boundary of the wound



KeloidExcessive build up of scar tissue that

invades the normal skin beyond the originalboundary of the wound



Thank you

Pa Tho Physiology of Wound Healing.ppt Rao 3

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