superficial introduction to the topic for bachelor level

1. Dr. Saugat Chapagain

2. • Body response to injury in an attempt to resist normal structure and function.
• Proceses:
1. Regeneration-
• Replacement of damaged cells by cells of same type.
• Via. Mitosis
2. Repair-
• Replacement of injured tissue by fibrous tissue.
• Process involved:
1. Granulation tissue formation – inflammation  clearance  angiogenesis/ fibrogenesis
2. Contraction of wounds

3. • Healing by 1st intention (primary)
• Clean and uninfected wound
• Surgically incised
• Without loss of cells and tissues
• Edges of wound are approximated by suturing
• Healing by 2nd intention (secondary)
• Open with large tissue defect; at times, infected.
• Excessive loss of cells and tissues.
• Not approximated by sutures, so left open.
• Healing by 1st and 2nd intention (tertiary)

5. • Initial haemorrhage-
o Blood clots and seals wound.
• Acute inflammation-
o Within 24 hrs, neutrophilic infiltration.
o Within 72 hrs, replaced by macrophages.
• Epithelial changes
o Basal cells of epidermis from both margins start proliferating.
o Well approximated wound is covered by epithelium in 48 hrs.
o Clot is pushed outward and scab is formed.
• Organization
o Fibroblasts invade by 3rd day.
o New collagen fibrils formed by 5th day.
o In 4 weeks complete epithelialized surface is formed.
• Suture tracks
o Each suture track is a site of healing by 1st intention.

6. • Initial haemorrhage
• Inflammatory phase
• Epithelial changes
• Granulation tissue
o Main bulk of secondary healing
o Formed by proliferation of fibroblasts and neovascularization
o Newly formed tissue  deep red, granular and fragile
o Mature tissue  pale and white d/t high collagen and low blood vessels
• Wound contraction
o Important feature in wound healing.
o d/t action of myofibroblasts in granulation tissue, wound contracts to 1-3rd to 1-4th of its
original size.
• Presence of infection
o Infection delays healing
o Surgical removal of dead and necrosed tissue, debridement helps in preventing infection.

7. Margins of wound Opposed Gap
Type Clean, surgical incision Large, infected wound
Tissue damage Minimum Marked
Bleeding Minimum More
Exudation Minimum More
Infection Absent Present
Granulation tissue Microscopic Grossly seen
Wound contraction Absent Occurs
Healing Heals quickly Takes time
Scar formation Small Large

8. • Infection
• Implantation (epidermal) cyst
• Pigmentation
• Deficient scar formation  ulceration, rupture or dehiscence.
• Incisional hernia
• Hypertrophied scars and keloid formation
• Hyalinization, calcification, ossification.
• Neoplasia

10. • Traumatic
• Pathological
• Complete or incomplete
• Simple (closed), comminuted (splintering of bone) or compound
(communicating to skin surface)

11. • Primary union:
• If ends of fracture is approximated without intervention.
• Medullary callus is formed without formation of periosteal callus.
• Ambulation can be early
• Secondary union:
• Procallus formation (within 1 week)
 Hematoma  local inflammatory response ingrowth of granulation tissue pro callus composed of
woven bone and cartilage
• Osseous callus formation (1-4 weeks)
 Procallus is calcified and ossification occurs
 Osteoclastic and osteoblastic activities
• Remodeling (1-2 years)

13. Please don’t get cut, bruised and keep your bones unfractured.