Wound II (Fall 2024) PDF

Wound II Professor/ Khaled Maher Lecturer of General surgery Faculty of Medicine, Delta University  Wound Healing Definition: It is the process by the body is trying to restore the anatomical integrity of the injured part & restore its full function. Types of...

Wound II Professor/ Khaled Maher Lecturer of General surgery Faculty of Medicine, Delta University  Wound Healing Definition: It is the process by the body is trying to restore the anatomical integrity of the injured part & restore its full function. Types of wound healing: 1) Primary Healing (First Intention): 1. It occurs in a clean incised wound or surgical wound. 2. Wound edges are approximated with sutures. 3. There is more epithelial regeneration than fibrosis. 4. Wound heals rapidly with complete closure. 5. Scar will be linear, smooth, & supple. 2) Secondary Healing (Second Intention): 1. It occurs in a wound with extensive soft tissue loss like in major trauma, burns & wound with sepsis. 2. It heals slowly with fibrosis. 3. It leads into a wide ugly scar, often hypertrophied & contracted. 4. It may lead into disability. 3) Tertiary Healing (Third Intention or Delayed Primary Closure): Primary contaminated or mixed tissue wounds heal by tertiary intention. Phases of Wound Healing: 1- Inflammatory phase (Lag or Substrate or Exudative Phase): 1. It begins immediately after formation & lasts for 72 hours. 2. There is initial arteriolar vasoconstriction, thrombus formation, platelet aggregation due to endothelial damage & release of adenosine diphosphate (ADP). 3. Later vasodilatation & increased vascular permeability develop. 4. Here hemostasis, coagulation & chemotaxis occur. 2- Proliferative Phase (Collagen/Fibroblastic phase): 1. It begins from 3rd day & lasts for 3–6 weeks. 2. There will be formation of granulation tissue & repair of the wound. 3. Granulation tissue contains fibroblasts, neocapillaries, collagen, fibronectin & hyaluronic acid. 4. Initial angiogenesis (growth of new blood vessels). 5. Then, there is fibroblast activity with formation of the collagen & ground substance/ glycosaminoglycans. Type III collagen is deposited initially in a random fashion. 6. Later re-epithelialisation of the wound surface occurs by migration of basal layer of the retained epidermis. 3- Remodeling phase (Maturation Phase): 1. It begins at 6 weeks & lasts for 6 months to 1 or 2 years. 2. There is maturation of collagen by cross linking & realignment of collagen fibers along the line of tension, which is responsible for tensile strength of the scar. 3. Fibroblast & myofibroblast activity cause wound contraction. 4. Type III collagen is replaced by type I collagen causing maturation of the collagen. 5. Scar strength is 3% in 1 week; 20% in 3 weeks; 80% in 12 weeks. Factors affecting Wound Healing: A) Local factors: 1. Infection. 2. Presence of necrotic tissue & foreign body. 3. Poor blood supply. 4. Tissue tension & hypoxia. 5. Hematoma. 6. Recurrent trauma. 7. X-ray irradiated area. 8. Site of wound, e.g. wound over the joints & back has poor healing. 9. Underlying diseases like osteomyelitis & malignancy. B) General Factors: 1. Age. 2. Obesity. 3. Smoking. 4. Alcohol. 5. Stress. 6. Malnutrition, zinc, copper, manganese. 7. Vitamin deficiency (Vit C, Vit A). 8. Anemia. 9. Jaundice. 10. Diabetes. 11. HIV & immunosuppressive diseases. 12. Steroids & cytotoxic drugs. Types of wound suturing: 1- Primary suturing: Suturing the wound immediately within 6 hours. It is done in clean incised wounds. 2- Delayed primary suturing: Suturing the wound in 48 hours to 10 days. It is done in lacerated wounds. This time is allowed for the oedema to subside. 3- Secondary suturing: Suturing the wound in 10–14 days or later. It is done in infected wounds. Complications of Wound Healing: 1- Failure of wound healing (wound dehiscence): Definition: failure of abdominal wall wound closure & it is called burst abdomen. If there is intestinal prolapse, it is called evisceration. Incidence: rare in young patients & occurs in about 5% of elder patients over 60 years old. Warning sign: serosanguinous discharge & soaking of the dressing. Treatment: 1. Cover the wound with sterile dressing. 2. IV fluids & antibiotics. 3. Surgical treatment by tension sutures. 4. Postoperative abdominal binder. 2- Stretching of scar. 3- Contracture: shortening of the scar with deformities. 4- Postoperative wound infection. 5- Hypertrophic scar. 6- Keloid formation.