WOUND:-
It is a discontinuity or break of the surface. An injury, especially one in which the skin or another external surface is torn, pierced, cut, or otherwise broken. Break in any body tissue due to external action (including surgery). It may be closed (blunt trauma) or open (penetrating trauma). Blood vessels, nerves, muscles, bones, joints, and internal organs may be damaged.

Types of Wound:-

• SIMPLE WOUND: Only skin is involved
• COMPLEX WOUND: It involves underlying nerves, vessels, tendons etc.
• INCISED WOUND : Theyare caused by sharp objects like knife or blades.
• LACERATED WOUNDS: They are caused by blunt objects like fall on a stone or due to road traffic accidents.
• PENETRATING WOUND:Not common nowadays.
• CRUSHED OR CONTUSED WOUND: Theyare caused due to blunt trauma due to run over vehicle, wall collapse etc.

HEALING:-

It is body response to injury in an attempt to restore normal structure and function.The process of healing involves 2 distinct process

• REGENERATION
• REPAIR

REGENERATION (BY CELL CYCLE): In this proliferation of parenchymal cells occurs and results in complete restoration of the tissue.

REPAIR:- In this replacement of injured tissue by fibrous tissue.Two processes occurs to repair the tissue:

1. Granulation tissue formation
2. Contraction of wound.
   • Granulation Tissue Formation
   • Phase of Inflammation: Acute inflamatory response is seen after injury.
   • Phase of Clearance: Phagocytic activity of macrophages clear off all the necrotic tissue and debris.
   • Phase of ingrowth of granulation tissue
   • Angiogenesis(Neovascularisation)
   • Fibrogenesis

Contraction of wound:-

Wound start contracting after 2-3 days of injury and whole process takes 14 days to complete. During this process wound reduced by 80%- 85% of its original size.

Mechanism of wound contraction:-

1. Dehydration occurs due to removal of fluid from tissue.
2. Contraction of collagen occurs due to decrease in collagen content of granulation tissue.
3. Myofibroblast migrates into the wound area and their contraction activity decreases the size of wound.

Wound Healing

Above picture shows the different cell activity at the site of wound

TYPES OF WOUND HEALING:-

• PRIMARY UNION ( FIRST INTENTION)
• SECONDARY UNION   (SECOND INTENTION)

Healing of a wound by first intention  which has the following characteristics.

1. Clean and uninfected wounds.
2. Surgically incised.
3. Without much loss of cells and tissues.
4. Edge of wound are approximated by surgical suture.

In fig A wound is filled with blood clot ans inflammatory response is seen. In fig B spurs of epidermal cells moves along margins and formation of granulation tissue occure. In fig C formation of scar is seen at site of suture track.

Sequence of events in first intention

1. Initial hemorrhage.
2. Acute inflammation.
3. Epithelial changes.
4. Organization.
5. Suture tracks.

HEALING BY SECOND INTENTION:-


Healing of a wound by second intention which has the following characteristics

1. Open with large tissue defects, at times infected
2. Having extensive loss of cells and tissues
3. The wound is not approximated by surgical sutures but it left open.

Sequence of events in second intention:-

1. Initial hemorrhage: In this wound space is filled with blood clot as a result of injury.
2. Inflammatory phase: phagocytic activity stars as a result of inflammation to clear off the debris.
3. Epithelial changes: proliferation and migration of different cells occurs to re-epithelialise the gap completely.
4. Granulation tissue: proliferation of fibriblasta and neovascularisation occurs which results in formation of granulation tissue. This constitute the main bulk of secondary healing.
5. Wound contraction:Myofibroblasts present in granulation tissue contracts the size of wound upto one- fourth of the original size.
6. Presence of infection: Bacterial activity  delays the wound healing. Debridement helps in preventing the open wound infection from bacterias.

In fig A open wound is filled with blood clot. In fig B epithelial cells from margins moves to middle to fill the gap of wound. In fig C wound contraction leads to smaller scar than the original size of wound.

Factors influencing healing:-

• LOCAL FACTORS:
  1. Type, Size and location
  2. Infection
  3. Poor blood supply
  4. Foreign bodies
  5. Movements
  6. Ionizing radiation

• SYSTEMIC FACTORS:
  1. Age
  2. Nutrition
  3. Systemic infection
  4. Administration of glucocorticoids
  5. Haematologic abnormalities

Nutrient Impacts on the Phases of Wound Healing

Wounding:Calendula succus – topical antimicrobial

Hemostasis:Drugs, herbs, vitamins, amino acids, or minerals that effect blood-clotting mechanisms should be avoided prior to surgery.

Inflammatory Phase: Vitamin A – enhances early inflammatory phase
Bromelain and adequate protein intake – prevent prolonging inflammatory phase
Vitamin C – enhances neutrophil migration and lymphocyte transformation

Proliferative Phase :Vitamin C – necessary for collagen synthesis

Centella asiatica – promotes type-1 collagen synthesis

Glucosamine – enhances hyaluronic acid production

Vitamin A – promotes epithelial cell differentiation

Zinc – required for DNA synthesis, cell division, and protein synthesis

Calendula succus and Aloe vera – support formation of granulation tissue

Remodeling:Protein deficiency – inhibits wound remodeling

Wound Care

Topical preparation
Aloe vera: Increases collagen content and degree of collagen cross-linkage within the wound.

Centella asiatica :Stimulates type-1 collagen production.

Honey or sugar paste : Glucose converted into hyaluronic acid at the wound surface forming an extra cellularmatrix that promotes wound healing; also considered antimicrobial.

Calendula succus: Anti-inflammatory and promotes
granulation.

Symphytum officinale: Promotes cell division and the growth of
bone, cartilage, and other connectivetissues; applied topically to closed wounds.

Complications of wound healing:-

• Infection
• Implantation Cyst
• Pigmentation
• Deficient scar formation
• Excessive contraction
• Neoplasia
• Hypertrophied scar and keloid formation

References

• Keast D, Orsted H. The basic principles of wound healing. http://www.cawc.net/open/conference/best-practice-series/Wound-
• Healing.pdf
• Stadelmann WK, Digenis AG, Tobin GR.Physiology and healing dynamics of chroniccutaneous wounds. Am J Surg 1998;176:26S-38S.
• 3. Stadelmann WK, Digenis AG, Tobin GR.Impediments to wound healing. Am J   Surg1998;176:39S-47S.
• Blee TH, Cogbill TH, Lambert PJ. Hemorrhageassociated with vitamin C deficiency insurgical patients. Surgery 2002;131:408-412.
• Cohen IK, Diegelman RF, Dome RY, et al. Wound careand wound healing. In: Schwartz SI, Shires GT, SpencerFC, et al, editors. Principles of surgery. seventh edition.
• New York: McGraw-Hill; 1999. p. 263 – 95.[2] Lawrence WT. Physiology of the acute wound. ClinPlas Surg 1998;25(3):321 – 40.
• [3] Cines DB, Pollack ES, Buck CA, et al. Endothelialcells in physiology and in the pathophysiology of vascular disorders. Blood 1998;91:3527 – 61.