1. Classification of Wounds, Principles of Wound Treatment

Wound

• Wound: Damage/disruption of the anatomical structure and function of epithelium and/or underlying tissue due to mechanical, thermal, chemical, electrical or radiation injury
• Can be intentional → Surgical wound
• Can be unintentional → Traumatic wound

Classification of Wounds

1. Depth of Penetration

• Superficial → Only epidermis
• Partial thickness → Reaches dermis
• Full thickness → Reaches subcutaneous adipose tissue
• Deep wound → Penetrates subcutaneous adipose tissue and beyond

2. Severity

• Simple → Involves skin and subcutaneous tissue only
• Complicated → Involves vessels, nn, tendons, bones, organs → Check PMS (pulse, motoric function, sensation)
• Special wounds → Diabetic foot, decubitus ulcer, chronic ulcer, burn, bite wound

3. Time Scale

• Acute → Occurs suddenly, heals at predictable/expected rate according to normal wound healing
• Chronic → Non-healing wound persisting beyond normal healing time
• Common chronic wounds → Diabetic foot ulcer, venous ulcer, arterial ulcer, pressure ulcer

4. Contamination

• Clean/sterile → Made under sterile conditions, low risk of infection
• Contaminated → Pathogenic organisms/foreign bodies may be present, usually traumatic wound
• Colonized → Bacteria present without invasive infection; common in chronic wounds
• Infected → Multiplying organisms + clinical signs

• Signs → Pain, erythema, warmth, swelling, pus/discharge, unpleasant smell, fever, lymphangitis

Mechanical Wounds

1. Open Wounds

• Internal tissues are exposed to the external environment
• Incision (vulnus scissum) → Caused by clean, sharp-edged object; regular wound edge
• Laceration (vulnus lacerum / caesum) → Caused by blunt trauma; irregular wound edge
• Abrasion (vulnus abrasum) → Epidermis scraped off by sliding on rough surface
• Avulsion (vulnus avulsum) → Tissue forcibly detached from insertion
• Contused-lacerated wound (vulnus contusum et lacerum) → Laceration + crushed/devitalized edges
• Puncture wound (vulnus punctum) → Narrow deep wound caused by pointed object
• Penetrating/perforating wound → Object enters body cavity/tissue; perforating wound has entry + exit
• Gunshot wound (vulnus sclopetarium) → Bullet injury; possible entry + exit wound, cavitation, tissue destruction
• Animal/human bite (vulnus morsum) → Usually polymicrobial, partially closed, high infection risk

2. Closed Wounds

• Skin is intact, underlying tissue is not directly exposed
• Contusion → Blunt trauma to small vessels, mm and soft tissue → Painful bruise
• Crush injury → High external pressure compresses tissue between surfaces
• Hematoma → Local collection of blood due to vessel injury → Painful, spongy/rubbery swelling

Non-Mechanical Wounds

1. Physical Wounds

• Thermal/burn wound (vulnus thermicum) → Injury caused by heat, flame, chemical, electricity, friction or radiation

• 1° burn → Epidermis only, hyperemia, painful, no blister
• 2° burn → Epidermis + part of dermis, blistering, painful
• 3° burn → Full thickness skin damage, leathery/black-white, less pain centrally due to nerve destruction

• Cold injury → Frostbite, tissue ischemia and necrosis
• Irradiation injury → Tissue necrosis, chronic ulceration, poor healing
• Electrical injury → Deep tissue damage may be greater than skin lesion

2. Chemical Wounds

• Acid → Coagulation necrosis
• Base/alkali → Liquefactive necrosis → Usually deeper penetration

Wound Assessment / Description

1. Type of wound + anatomical location
2. Size → Length × width × depth
3. Depth, contamination, foreign body, necrosis, bleeding
4. Damage to vessels, nerves, tendons, bones, organs → PMS + active movement
5. Wound edge → Sharp, irregular, crushed, macerated, undermined
6. Wound bed → Granulation, slough, necrosis, pus
7. Exudate/odor
8. Surrounding tissue → Erythema, edema, ischemia, cellulitis
9. Pain + functional impairment
10. Patient factors → Diabetes, immunosuppression, anticoagulation, tetanus status

Wound Healing

• Wound healing: Process restoring anatomical integrity and function by epithelial regeneration + connective tissue scar formation

Phases of Wound Healing

1. Hemostasis/coagulation

• Injury → Vasoconstriction → Platelet activation → Clotting cascade → Fibrin clot

2. Inflammatory phase (approx. day 1-4/6)

• PMNs + macrophages remove bacteria, clot and necrotic tissue
• Macrophages → Growth factors/cytokines → Stimulate fibroblasts and angiogenesis
• Clinically → Erythema, edema, warmth, pain; excessive bacteria → Infection

3. Proliferative phase (approx. day 4-21)

• Angiogenesis → VEGF, FGF
• Fibroblast proliferation → Collagen matrix
• Granulation tissue formation
• Re-epithelialization from wound edges

4. Remodeling/maturation phase (weeks-months)

• ↓ Cellularity, ↓ vascularity
• Collagen remodeling + cross-linking → ↑ tensile strength
• Myofibroblasts contract wound → Scar flattens and becomes pale

Types of Wound Healing / Closure

1. Healing by Primary Intention

• Clean wound edges are approximated by sutures/staples/adhesive
• Minimal granulation tissue, rapid healing, good cosmetic result
• Typical → Clean surgical wound, fresh clean traumatic incision
• Not for → Bite wounds, gunshot wounds, deep puncture wounds with foreign body, heavily contaminated/crushed wounds

2. Healing by Secondary Intention

• Wound left open → Granulation tissue + contraction + epithelialization
• Used when infection, necrosis, tissue loss or high contamination is present
• Dressing with moist gauze/modern wound dressing → Regular reassessment and debridement
• Slower healing, larger scar

3. Healing by Tertiary Intention

• Delayed primary closure
• Initially treated open like secondary intention → Irrigation/debridement/dressing
• Closure after approx. 3-5 days if wound is clean and no infection
• Better cosmetic result than secondary intention + lower infection risk than immediate closure

Principles of Wound Treatment

1. Primary survey if trauma → ABCDE, control life-threatening bleeding
2. Analgesia/local anesthesia
3. Expose and inspect wound → Depth, contamination, foreign body, devitalized tissue
4. Assess function → PMS, tendon movement, joint involvement, fracture signs
5. Imaging if needed → X-ray/US/CT for foreign body, fracture, deep injury
6. Microbiology sample → If infected, purulent discharge, chronic wound or bite infection
7. Mechanical cleaning/irrigation → Saline; remove dirt and foreign material
8. Antisepsis of surrounding skin → Avoid toxic antiseptic deep inside delicate tissue if possible
9. Debridement → Remove necrotic/devitalized tissue and refresh wound edges if needed
10. Hemostasis → Compression, ligation, cautery; avoid blind clamping near nn/vessels
11. Antibiotics when indicated
12. Wound closure strategy → Primary / secondary / delayed primary closure
13. Dressing + immobilization/elevation if needed
14. Tetanus prophylaxis ± rabies/blood-borne virus risk assessment in bites
15. Follow-up → Recheck high-risk wounds within 24-48 h

Wound Closure Strategy

Antibiotic Principles

• Not every wound needs antibiotics → Irrigation + debridement are most important
• Indications → Infected wound, bite wound with risk factors, gross contamination, open fracture, deep puncture, crush injury, immunosuppression/diabetes, delayed presentation
• Bite wound first choice → Amoxicillin/clavulanate (co-amoxiclav)
• Penicillin allergy in adult bite wound → Doxycycline + metronidazole; pregnancy → seek specialist advice
• Prophylaxis duration for bites often 3 days; treatment of infected bite often 5 days, extend if severe/deep involvement
• Take swab if discharge/pus is present → Adjust antibiotic according to culture

Tetanus Prophylaxis

• Assess wound type + vaccination history
• Dirty/major tetanus-prone wounds → Puncture/penetrating wound, soil/feces/saliva contamination, bite wound, burn, crush injury, frostbite, necrotic/gangrenous wound, compound fracture

• TIG = tetanus immunoglobulin; neutralizes circulating toxin only
• Antibiotics are not used specifically to prevent tetanus

Factors Affecting Wound Healing

1. Local Factors

• Wound type, size, location, tension
• Poor vascular supply/oxygenation
• Infection, foreign body, necrosis, hematoma/seroma
• Repeated trauma, edema, pressure

2. Systemic Factors

• Age, obesity, malnutrition, vitamin/protein deficiency
• Diabetes mellitus → Micro-/macroangiopathy + neuropathy + infection risk
• Anemia, shock, peripheral arterial disease, venous insufficiency
• Immunosuppression, malignancy, renal/liver failure
• Smoking/alcohol → Vasoconstriction, impaired oxygenation and immune response

3. Drugs

• Corticosteroids → ↓ Inflammation, ↓ fibroblast activity, ↓ collagen synthesis
• Cytotoxic chemotherapy / immunosuppressants → ↓ cell proliferation and infection control
• NSAIDs may impair early inflammatory phase if excessive

Complications of Wound Healing

Early Complications

• Bleeding/hematoma → Painful swelling; infection risk
• Seroma → Collection of serous fluid/lymph

• Treatment → Sterile puncture/aspiration + compression; suction drain if recurrent/large

• Wound infection → Superficial / deep / organ-space

• Treatment → Open wound if needed, drainage, debridement, culture, antibiotics

• Wound dehiscence/disruption → Failure of wound closure

• Causes → Infection, hematoma, poor suturing, ↑ intra-abdominal pressure, malnutrition
• Treatment → Re-suture; abdominal wound may need retention/U-shaped sutures

Late Complications

• Hypertrophic scar → Excess collagen within wound borders; may regress
• Keloid → Excess scar tissue extends beyond wound borders; itchy/painful; does not regress reliably

• Treatment → Silicone sheet/gel, pressure therapy, intralesional steroid, excision + adjuvant therapy in selected cases

• Chronic wound/ulcer → Persistent inflammation + impaired healing
• Fistula/sinus tract → Persistent pathological tract, often due to infection/foreign body
• Contracture → Scar shortening causing functional limitation, especially after burns