WOUNDS - Lecture Notes PDF

Al-Hadba University College of health and medical techniques Department of Anesthesia techniques WOUNDS, TISSUE REPAIR, AND SCARS Dr Hisham Hammodat MBChB CABS FRACS ‫ﺸﺎم ﺣﻤﻮدات‬$.‫د‬ ‫ﺸﺎري أﻗﺪم‬1‫ﺟﺮ...

Al-Hadba University College of health and medical techniques Department of Anesthesia techniques WOUNDS, TISSUE REPAIR, AND SCARS Dr Hisham Hammodat MBChB CABS FRACS ‫ﺸﺎم ﺣﻤﻮدات‬$.‫د‬ ‫ﺸﺎري أﻗﺪم‬1‫ﺟﺮاح اﺳ‬  DEFINITION AND TYPES OF WOUNDS A wound is defined as a disruption or injury to the integrity of the skin or underlying tissues. Different classifications: 1. Open or Closed, according to exposure to the exterior. Open wounds have the underlying tissue and/or organs open to the outside environment. Closed wounds have damage that occurs without exposing the underlying tissue and organs. 2. Acute or Chronic, according to the healing time. Chronic wounds take a longer time to heal and might have some complications compared to acute wounds. 3. According to the Degree of Contamination. Clean, clean contaminated, contaminated or dirty.  TYPES OF WOUNDS Open wounds include: 1. Incision: Caused by a sharp object, such as a knife or glass. 2. Laceration: Irregular, jagged wounds caused by tearing or crushing forces.  TYPES OF WOUNDS 3. Puncture: Resulting from a sharp, pointed object penetrating the skin. 4. Penetrating: caused by a foreign object piercing the skin resulting in damage to underlying structures. 5. Abrasion: Superficial wound caused by friction or scraping of the outer skin layer.  TYPES OF WOUNDS 6. Avulsion: Tissue forcibly torn away or separated from the body. 7. Burns: Injuries caused by thermal, chemical, electrical, or radiation sources.  TYPES OF WOUNDS Closed wounds: These are usually the result of blunt trauma or friction with other surfaces; the wound does not break through the skin. 1. Contusion: Superficial spread of blood under the skin resulting from break in small blood vessels. 2. Haematoma: Pooling of blood from a break in blood vessels.  PHASES OF WOUND HEALING Wound healing is a complex and dynamic process that involves a series of overlapping phases. The FOUR main phases of wound healing are: 1. Hemostasis phase: begins immediately after injury with vasoconstriction of blood vessels and platelet aggregation to initiate the process of thrombosis and stop the bleeding.  PHASES OF WOUND HEALING 2. Inflammatory phase: This phase begins soon after injury and lasts for several days (typically 3-7 days). Key cells involved are: Neutrophils First responders that help clear debris and pathogens through phagocytosis.and macrophages: Arrive later to clear debris and secrete growth factors that promote healing. Mast Cells: Release histamine and other mediators that contribute to inflammation.  PHASES OF WOUND HEALING 3. Proliferative phase: Lasts from several days to a few weeks (typically 1-3 weeks). During this phase, new tissue (Granulation Tissue) is formed to fill the wound space. ] Fibroblasts synthesize Collagen (the main protein responsible for wound strength) and Extra-Cellular Matrix. New blood vessels formation (angiogenesis) to supply oxygen and nutrients to the healing tissue. Epithelial cells at the wound edges migrate to cover the wound surface, a process known as re- epithelialization.  PHASES OF WOUND HEALING 4. Remodelling phase: This final phase involves the maturation and remodelling of the newly formed tissue. typically lasts from 3 weeks to several months, but can extend up to 1 year or longer. Collagen fibers reorganize and strengthen, and excess cells are removed. The scar tissue gradually gains strength and achieves maximal tensile strength at around 12 weeks (3 months), but generally only having 80% of the tensile strength of unwounded skin.  FACTORS AFFECTING WOUND HEALING Local & Systemic factors: Local factors: 1. Infection: Infection can delay wound healing and increase the risk of complications. Proper wound care and infection control are critical. Wound Infection  FACTORS AFFECTING WOUND HEALING 2. Tissue oxygenation: is crucial for optimum wound healing. Lack of blood supply and poor oxygenation lead to poor wound healing because of: Ø Prolongation of the inflammatory phase leading to persistent (chronic) inflammation. Ø Poor angiogenesis, Ø Impaired keratinocyte differentiation, migration, and re-epithelialization, Ø Impaired fibroblast proliferation and collagen synthesis, leading to weak scar formation Ø Increased risk of wound infection due to impaired function of immune cells. All of the above will lead to a chronic wound that fails to heal (ulcer). Ischemic (Arterial) Ulcer  FACTORS AFFECTING WOUND HEALING 3. Venous insufficiency: This leads to venous stasis resulting in increased venous pressure which can damage surrounding tissues oedema (swelling) that impairs nutrient delivery and oxygen supply chronic inflammation All of the above leads to skin breakdown, resulting in ulcers that are difficult to heal. 4. Mechanical factors: Tension, pressure, or excessive movement at the wound site can impair healing and lead to increased scar formation. Venous Insufficiency leading to Venous Ulceration FACTORS AFFECTING WOUND HEALING 5. Wound Size and Depth: Larger and deeper wounds take longer time to heal. 6. Foreign body 7. Ionizing radiation 8. Faulty surgical technique  FACTORS AFFECTING WOUND HEALING Systemic factors: 1. Age: Elderly individuals generally have slower wound healing due to reduced cell proliferation and decreased collagen synthesis. 2. Chronic diseases: Conditions such as diabetes, cardiovascular disease, and immunodeficiency disorders can impair wound healing by affecting blood flow, immune response, and cellular function.  FACTORS AFFECTING WOUND HEALING 3. Cigarette smoking: o Nicotine induces Wound Ischemia by: - causing vasoconstriction. - fibrinolysis more viscous blood tissue/regional blood flow. - Carbon monoxide (CO) decreases haemoglobin oxygen carrying capacity. o Immunopathy: impaired leukocyte migration into the wound o Weak Scar: impaired fibroblast migration and proliferation FACTORS AFFECTING WOUND HEALING 4. Nutritional status: Adequate intake of proteins, vitamins (especially vitamin C and vitamin A), and minerals is essential for optimal wound healing. 5. Medications: Certain medications, such as corticosteroids, chemotherapy and immunosuppressants, can interfere with the healing process.. FACTORS AFFECTING WOUND HEALING 6. Genetic diseases: e.g. Ehler’s Danlos syndrome and hyperhomocysteinemia 7. Alcohol intake 8. Obesity 9. Stress  WOUND HEALING BY PRIMARY INTENTION VS SECONDARY INTENTION Primary intention occurs in wounds with skin edges that are close together. Secondary intention occurs when the sides of the wound are not opposed, therefore healing must occur from the bottom of the wound upwards.  SCAR FORMATION Scarring is a natural part of the wound healing process, but the extent and appearance of scars can vary. Factors that influence scar formation include: 1. Wound characteristics: Larger, deeper, or more severe wounds are more likely to result in noticeable scars. 2. Wound location: Areas with high tension, such as joints or the chest, are prone to more prominent scars.  SCAR FORMATION 3. Genetic factors: Individual variations in collagen production and remodeling can affect scar formation. 4. Infection: Infected wounds are more likely to develop hypertrophic or keloid scars, which are raised, thickened, and extend beyond the original wound boundaries. 5. Poor wound care: Inadequate wound cleaning, excessive moisture, or repeated trauma can contribute to abnormal scar formation. Keloid scar Hypertrophic scar  SCAR MANAGEMENT While scars cannot be completely eliminated, various strategies can help manage and improve their appearance: 1. Wound care: Proper wound cleaning, protection, and dressings promote optimal healing and minimize scar formation.  SCAR MANAGEMENT 2. Topical treatments: Silicone gels, sheeting, and certain creams or ointments may be used to hydrate the scar, reduce redness, and flatten raised scars.  SCAR MANAGEMENT 3. Corticosteroid injections: Intralesional injections of corticosteroids can help reduce inflammation and flatten raised scars, such as hypertrophic or keloid scars. 4. Laser therapy: Various laser treatments, such as fractional laser resurfacing or pulsed dye laser, can improve scar redness, texture, and thickness.  SCAR MANAGEMENT 5. Surgical interventions: In some cases, surgical techniques like scar revision or scar excision may be considered to modify the appearance of scars. 6. Psychological support: Emotional support and counseling can be beneficial for individuals who experience distress or body image concerns related to their scars.  COMPLICATIONS OF WOUND HEALING While wound healing is usually a well- coordinated process, certain complications can arise: 1. Infection: Wounds can become infected, leading to delayed healing, increased pain, and potential systemic spread of infection. Timely detection and appropriate treatment are crucial. Wound Infection  COMPLICATIONS OF WOUND HEALING 2. Excessive scar formation: Hypertrophic scars and keloids (scars beyond the boundaries of the wounds) can cause functional and aesthetic concerns. Keloid scar Hypertrophic scar  COMPLICATIONS OF WOUND HEALING 3. Delayed wound healing: Some wounds may exhibit slow healing, often due to underlying health conditions, poor blood supply, or inadequate wound care. 4. Wound breakdown: This refers to the partial or complete separation of wound edges, which can increase the risk of infection and require prompt medical attention. Wound breakdown  COMPLICATIONS OF WOUND HEALING 5. Abdominal wound dehiscence: is the re-opening of all the layers of a closed surgical wound with a risk of protrusion (evisceration) of the underlying abdominal structures, e.g. the bowel. Abdominal wound Bowel Evisceration dehiscence COMPLICATIONS OF WOUND HEALING 6. Contractures: In some cases, especially with burn injuries, excessive wound contraction can lead to limited mobility and functional impairment. Wound Contracture SURGICAL WOUND CLASSIFICATION Surgical wound classification is a system primarily based on the degree of contamination present at the time of surgery. The classification system helps to: Ø predict the risk of surgical site infections (SSI) and Ø guides postoperative care, such as antibiotic prophylaxis and wound care. It is classified into FOUR classes  SURGICAL WOUND CLASSIFICATION 1. Class I: Clean Wound – ü includes elective, non-traumatic, and non-infected surgical procedures performed under controlled conditions. ü the surgical site does not involve the respiratory, gastrointestinal, urogenital, or oropharyngeal tracts. ü Clean wounds have a low risk of infection (1%-5%). 2. Class II: Clean-Contaminated Wounds - have a low level of contamination. ü These types of wounds involve entry into the respiratory, alimentary, genital, or urinary tracts but only under controlled circumstances, without significant spillage or contamination. ü The risk of infection is 3%-11%  SURGICAL WOUND CLASSIFICATION 3. Class III: Contaminated Wound - Contaminated wounds ü occur in the presence of acute inflammation or major breaks in sterile technique. ü They involve traumatic wounds >4 hours old, or ü operations with major spillage from the gastrointestinal tract or infected operative fields. ü These wounds have a higher risk of infection (10%-17%) due to the presence of bacteria. 4. Class IV: Dirty or Infected Wound - Dirty or infected wounds ü are characterized by established infection, extensive inflammation, or the presence of devitalized tissue. Examples include wounds with pus, perforated viscera, or traumatic wounds with evidence of infection. ü These wounds have the highest risk of infection over 27%.  CONCLUSION Wound healing is a complex and dynamic process involving a series of carefully orchestrated events. Understanding the phases of wound healing, factors influencing scar formation, and strategies for scar management is crucial for healthcare professionals involved in wound care. By optimizing wound management, providing appropriate interventions, and addressing patient concerns, healthcare providers can help promote optimal healing outcomes and improve the quality of life for individuals with wounds and scars.  MCQ’S 1. What is the definition of a wound? o A) A disease affecting internal organs o B) A disruption or injury to the integrity of the skin or underlying tissues o C) A condition affecting the immune system o D) A sprain or strain of muscles o E) A fracture of bones 2. Which of the following is NOT a type of open wound? o A) Incision o B) Laceration o C) Contusion o D) Puncture o E) Avulsion 3. What characterizes the inflammatory phase of wound healing? o A) Platelet aggregation o B) Formation of new blood vessels o C) Influx of immune cells to the wound site o D) Re-epithelialization o E) Collagen reorganization  MCQ’S 4. Which factor can delay wound healing? o A) Proper wound care o B) Adequate nutrition o C) Chronic diseases o D) Controlled wound environment o E) Early mobilization 5. What is the role of fibroblasts in wound healing? o A) Initiate blood clotting o B) Synthesize collagen o C) Regulate immune response o D) Increase blood flow o E) Absorb excess fluid 6. Which phase of wound healing involves the reorganization of collagen fibers? o A) Hemostasis phase o B) Inflammatory phase o C) Proliferative phase o D) Remodeling phase o E) Initial phase  MCQ’S 7. Which type of wound is typically caused by a sharp object, such as a knife or glass? A) Puncture B) Laceration C) Incision D) Avulsion E) Contusion 8. What is the effect of cigarette smoking on wound healing? A) It enhances collagen synthesis B) It promotes rapid healing C) It induces wound ischemia D) It increases immune cell function E) It has no effect 9. What is the major characteristic of a clean-contaminated surgical wound? A) It has a high level of contamination B) It includes elective, non-traumatic procedures C) It involves entry into the respiratory or alimentary tracts under controlled conditions D) It is characterized by established infection E) It is considered a superficial wound  MCQ’S 10. Which class of surgical wound has the highest risk of infection? o A) Class I: Clean Wound o B) Class II: Clean-Contaminated Wound o C) Class III: Contaminated Wound o D) Class IV: Dirty or Infected Wound o E) Class V: Superficial Wound