For Medical knowledge

1. WOUND HEALING

2. Wound & Wound Healing
 Definition:
 Breach in continuality of epithelial lining surface due
to injury & trauma.
 Classification of wound:
 Depend on degree of contamination.
 Depend on causal agents/morphology.

3. Depend on degree of contamination.
 Clean wound
 Wound without contamination.
(e.g. Clean surgical wound under aseptic condition;
Thyroid, Breast, Lipoma Surgery.)
 Clean contaminated wound
 Wound with minimal or potential contamination.
(e.g. Surgical wound made on potentially
contaminated area (upper GI surgery-stomach,
biliary)
Traumatic clean wound within six hours after
trauma.)

4.  Contaminated wound
 Wound with gross contamination.
(e.g. Surgical wound made on contaminated area
(colonic surgery)
Traumatic wound > six hours, with
contaminated soil)
 Dirty/ Septic wound
 Wound contaminated with pathogenic organisms
(e.g. Wound made on gross sepsis-peritonitis,
abscess)

5. Depend on Causal agents/ Morphology
 Incised wound
 Due to sharp weapon
 Minimal tissue loss, edge opposed together & even
 Rapid healing when wound is clean & closed primarily,
increased tensile strength, minimal scar
 Lacerated wound
 Due to blunt object
 Variable amount of tissue loss, haematoma, edge is uneven
& rages
 More time need to heal (because of increase tissue loss &
presence of haematoma) reduced tensile strength,
increased scar

6.  Crush wound
 Tissue crush between two hard objects
 Large amount of tissue loss, haematoma, unexpected
amount of devitalised tissue at first, and then loss of tissue
depend on force & extend of crush injury
 Delay wound healing, reduced tensile strength, increased
scar
 Penetrating wound
 Due to sharp & pointed weapon
 Minimal tissue loss but can’t expect depth of wound
 Increase chance of anaerobic condition-tetanus

7. Types of Wound Healing
 First intention
 In clean surgical wound/incised wound, wound edge
opposed together by suture wound healing is
rapid from edges as well as base, increased tensile
strength & minimal scar formation
 Second intention
 In case of contaminated/dirty wound with variable
amount of tissue loss- healing arise from base -
healing is delayed & need long time- reduced tensile
strength, increased scar formation

8.  Third intention
 In case of contaminated wound with minimal tissue
loss, wound wait to clean as open wound ( due to
infection more susceptible in close wound)- closed
the wound with suture when the wound is clean (
delay primary closure) or secondary closure.

9. Elements of Wound Healing
1. Epithelialization
 Migration, proliferation of epithelial tissue from the
edges & epidermal layer of wound to cover the
wound
2. Wound contraction
 In open wound, the size of wound become smaller
by contraction of myofibroblast to wound healing
3. Connective tissue formation
 Main body of wound is united by synthesis & lysis of
collagen tissue from fibroblast & new capillary
formation ( granulation tissue)

10. Phase of Wound Healing
1. Lag (or) Preparatory phase
 First few hours to days of wound- infiltration of
neutrophil & macrophages- demolition of
inflammatory exudate & devitalised tissue
2. Repair (or) Proliferated (or) Fibroblastic phase
 First few days of wound- macrophages- attract the
fibroblast & synthesis of collagen tissue &
intercellular ground substance & new formation of
blood vessels ( granulation tissue) filled up the
wound wound healing.

11. 3. Maturation (or) Differentiation phase
 Reduced activity of fibroblast & increasing tensile
strength of wound need months to years until
normal tensile strength regained (very rare).
 50% to 70% of tensile strength regained by the end
of six months

12. Process of wound healing
 Epidermal events
 Dermal events
 Collagen production

13. Epidermal events
 Particularly in surgical wd, incised wd within few hrs
 Primary single layer of epithelial cell starts to migrate
from edge to form delicate covering over wd
 Followed by epithelial cell proliferation from epidermal
cells
 (Implantation dermoid – In small penetrating wd(
needle prick) down growth of epidermal cell –keratin
forming cyst within dermis known as implantation
dermoid

14. Dermal events
 Within few hrs, mild acute inflammatory infiltration of
neutrophil into and around wd followed by migration of
macrophages (1-2)hrs after wound
 Demolition and removal of inflammatory exudate and
tissue debris
 Restoration of tensile strength of sub epithelial
connective tissue
• Chemoattraction of fibroblasts synthesis secretion
of collagen and ground substance
• Expansion of fibroblast population
• Secretion of extracellular connective tissue protein
for fibroblast

15.  Ingrowth of new small bld v/s
 Budding of new endothelial cell from intact bld v/s of
edges
 Chemoattraction of these new bld vs into connective
tissue of wd

16. Collagen production
 Over half of collagen made up with 3 amino acids; lysine,
hydroxyprolene, prolene
 Fibroblast ; synthesis new collagen intercellular ground
substance production of 3 main amino acids and cross
linkage of each other > connective t/s formation> tensile
strength of wd

17.  Tensile strength depends on production of amount of
collagen and their orientation. This process is maintained
by production and destruction of collagen (collagen
synthesis and lysis)
 Inbalance between this process>wd complication
 Decrease synthesis ,increase lysis > impaired wd
healing and dehiscence
 Increased synthesis, decrease lysis > hypertrophic
scar keloid formation

18. Factors affecting wound healing
 General factors
(1) Age - young age - increased blood supply- good
wound healing
- old age - reduced blood supply & associated
diseases- impair wound healing
(2) Nutritional status
(1) Overnutrition - (2) Undernutrition

19. (1) Overnutrition - obesity- increased fatty tissue-
(a) reduced supportive tissue to blood vessels- fragile, easy
to bleed
(b) retraction of blood vessel- difficult to control healing
(c) increased tissue destruction, dead space
(2) Undernutrition
hypoproteinaemia- impair amino acid synthesis
hypovitamin C (surgery) – impair collagen synthesis
(hydroxylation)
hypovitamin A – epidermal growth reduced
zinc – impair wound healing- because of decrease collagen
synthesis

20. (3) Associated diseases
-jaundice
-uraemia
-anaemia-reduced Hb – decreased oxygen carrying capacity
-diabetes mellitus – decreased immunity, reduced blood
supply, increased infection
-impaired cardiopulmonary status- reduced oxygen supply to
tissue
(4) Immunity
-reduced immunity- increase infection-
due to disease - burn, DM, HIV, trauma, Ca
due to drugs - steroid, chemotherapy,
immunosuppressive therapy
Increased collagen breakdown

21.  Local factors
1. Site- face- increased blood supply- increased wound
healing
2. Presence of foreign body + contamination- increased
infection- reduced oxygen supply- impaired wound
healing
3. Underlying vascular diseases –artery-reduced blood
supply, venous stasis- reduced oxygen supply
4. Presence of tension- reduced blood supply- to
wound- haematoma, dead space
oxygenation
infection

22. 5.Improper surgical technique
-over or under haemostasic,
-suture (improper use) rough handling
6.Excessive irritation-
-collagen destruction increased
7.Local R/T - cell destruction
-radiation vasculitis- reduced blood supply

23. Complication of wound healing
 Early- wound break down- complete & partial
- wound infection
 Late - incisional hernia
- scar- keloid, hypertrophic, contracture

24. Hypertrophic Keloid
Time factor Regress after 6 months Continue after 6 months
Tendency No previous Previous tendency
Site Any site Over the bony prominent
e.g. sternum
Extend beyond the
margin of wound
Never Presence
Treatment No active treatment required Active treatment required –
injection steroid, pressure
dressing, R/T
Complication - Malignant change – Marjolin’s
ulcer

25. Principle of wound management
 Clean wound – closed by primary intention
 Contaminated wound – change to clean wound –
closed
 Depend on - amount of contamination
- type of wound

26. A. Specific treatment
Contaminated wound- change to clean wound by-
1. “wound toilet”- irrigation of wound with sterile water including
antiseptic solution - to reduce contamination & remove foreign
body
2. “wound debridement”- excision of dead & devitalised tissue under
appropriate GA/LA/Reagional
 Skin – as little as possible (easy to close the wound)
 Subcut :fat & tls – as much as possible
 Mls – till bleed ( viable mls )
 Tendon – color suture for delayed repair
 Nv – primary repair / delayed repair mark with suture

27.  Bld v/s -Small v/s – haemostasis
-Major v/s – primary repair / graft
 Bone - detached bone & pieces from periosteum
removed
- Reduction & traction by external fixator or POP
with windows for dressing

28. B. Supportive / symptomatic treatment
- Analgesic & antiinflammatory drugs - for pain & inflammation
- Antipyretic drugs – pt with febrile reaction
- Antibiotic – according to possible organ ( or ) C&S result
- tetanus prophylaxis – tetanus toxoid – active for regular
immunized person
– both active & passive in pt who has no
regular immmunization
- Nutritional support
- Correct the factors which delayed the wd healing e.g
Correction of Anaemia, Diabetes mellitus

29. C. Treatment of clean wd / wd become clean from
contaminated wound
- Skin closure d/on type of wound
( 1 ) when skin can oppose together eg .in incise &
lacerated wound ( less tissue loss )
- Primary closure – for clean wound.
- delayed primary closure – for contaminated wound.

30. - secondary closure – clean wound become
contaminated
- after primary closure & remove the suture and then
wait for clean wound and then reapplication of
suture
( 2 ) when skin cannot oppose together (tissue loss very
much) crush wound
a. Close the wound by – skin graft ( to fasten the wd
healing ) ( or )
b. Left the wound open and healing from base of
wound ( wd complication increased )