OPT 329 Wound Repair

What are 2 benefits of eyelid skin being thin?

rapid healing

does not scar much

What affects the speed of recovery in eyelid wounds?

depth

size

microbial contamination

allergies

pt factors = genetics, comorbidities (DM)

What are the 3 phases of eyelid wound healing?

inflammatory phase

proliferative phase

remodeling phase

What are the 2 types of fibrosis which are possible complications of healing?

scar = deformity across the joint of the wound

OR

keloid = deformity beyond the joint of the wound

What is a scar?

replacement of original skin tissue (reticular/basket weave collagen) with collagenous tissue = more densely packed parallel collagen = altered appearance, less elasticity

What do scars lack?

dermal appendages such as hair follicles, sebaceous glands

How does the colouration of a scar change over time?

red at first due to high capillary density that will regress

pigmentation increases over time depending on pt pigment

What causes a hypertrophic or keloid scar?

excess inflam mediators due to excess macrophage activity (poor signaling among macropahges, fibroblasts, epithelial and endothelial tissue)

fibrosis due to excess fibroblast activity and overproduction of collagen

excess epithelial mesenchymal transition

chemotactic factors

What is a hypertrophic scar?

does not go beyond wound border but is raised, red, itchy from excess tension (esp across joints/tendons) = may fade or flatten over time

What is a keloid scar?

extends beyond wound border because it infiltrates surrounding tissue

does not regress and may progress or evolve over time

collagen is very disorganized (unlike parallel in a scar)

How do hypertrophic and keloid scars differ in terms of onset?

hypertrophic scar = develops soon after surgery

keloid = can develop months after trauma

How do hypertrophic and keloid scars differ in terms of improvement over time?

hypertrophic scar = usually improve with time

keloid = rarely improve with time

How do hypertrophic and keloid scars differ in terms of boundaries?

hypertrophic scar = remain within confines of wound

keloid = spread outside boundaries of wound

How do hypertrophic and keloid scars differ in terms of body location?

hypertrophic scar = scars over joints, skins creases

keloid = ear lobe, shoulders, sternal notch

How do hypertrophic and keloid scars differ in terms of improvement after Sx?

hypertrophic scar = improve with surgery

keloid = often worsened by surgery

How do hypertrophic and keloid scars differ in terms of rarity?

hypertrophic scar = frequent

keloid = rare

How do hypertrophic and keloid scars differ in terms of skin colour association?

hypertrophic scar = no assocation

keloid = increased risk in darker skin colour

What are some ways to reduce complications like scars?

incisions parallel to natural tension (Langer) lines to prevent tension and blend with natural creases

sharply defined, well aligned edges

infection management through asepsis

wound closure with sutures

sun protection

silicone gel sheeting/ointments to hydrate straum corneum

steroid injection for keloids

What is this alternative to excisions? Include the 2 MOA's of this tx.

chemical cautery with DCA, TCA (di or tri-chloracetic acid) = keratolytic and cauterant properties break down hyperkeratinized superficial lesions

What is the process for chemical cautery?

proparacaine to reduce tearing from fumes

apply petroleum jelly to prevent compounding running to other areas

apply chemical on lesion with an applicator (may burn or sting slightly)

affected tissue turns white and may slough off to leave a small scab

apply abx/steroid ung to scab